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tsvm/video_encoder/encoder_tev.c
minjaesong 5c87325366 fix: wrong subtitle timecode on certain SRT files
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// Created by CuriousTorvald and Claude on 2025-08-18.
// TEV (TSVM Enhanced Video) Encoder - YCoCg-R/ICtCp 4:2:0 16x16 Block Version
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stddef.h>
#include <string.h>
#include <math.h>
#include <zstd.h>
#include <unistd.h>
#include <sys/wait.h>
#include <getopt.h>
#include <ctype.h>
#include <sys/time.h>
#include <time.h>
#include <limits.h>
// TSVM Enhanced Video (TEV) format constants
#define TEV_MAGIC "\x1F\x54\x53\x56\x4D\x54\x45\x56" // "\x1FTSVM TEV"
// TEV version - dynamic based on colour space mode
// Version 2: YCoCg-R 4:2:0 (default)
// Version 3: ICtCp 4:2:0 (--ictcp flag)
// version 1: 8x8 RGB
// version 2: 16x16 Y, 8x8 Co/Cg, asymetric quantisation, optional quantiser multiplier for rate control multiplier (1.0 when unused) {current winner}
// version 3: version 2 + internal 6-bit processing (discarded due to higher noise floor)
// Block encoding modes (16x16 blocks)
#define TEV_MODE_SKIP 0x00 // Skip block (copy from reference)
#define TEV_MODE_INTRA 0x01 // Intra DCT coding (I-frame blocks)
#define TEV_MODE_INTER 0x02 // Inter DCT coding with motion compensation
#define TEV_MODE_MOTION 0x03 // Motion vector only (good prediction)
// Video packet types
#define TEV_PACKET_IFRAME 0x10 // Intra frame (keyframe)
#define TEV_PACKET_PFRAME 0x11 // Predicted frame
#define TEV_PACKET_AUDIO_MP2 0x20 // MP2 audio
#define TEV_PACKET_SUBTITLE_TC 0x31 // Subtitle packet with timecode (SSF-TC format)
#define TEV_PACKET_SYNC 0xFF // Sync packet
// Utility macros
static inline int CLAMP(int x, int min, int max) {
return x < min ? min : (x > max ? max : x);
}
static inline float FCLAMP(float x, float min, float max) {
return x < min ? min : (x > max ? max : x);
}
// Which preset should I be using?
// from dataset of three videos with Q0..Q95: (real life video, low res pixel art, high res pixel art)
// 56 96 128 192 256 Claude Opus 4.1 (with data analysis)
// 64 96 128 192 256 ChatGPT-5 (without data analysis)
static const int MP2_RATE_TABLE[] = {128, 160, 224, 320, 384, 384};
// Valid MP2 bitrates as per MPEG-1 Layer II specification
static const int MP2_VALID_BITRATES[] = {32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384};
// Validate and return closest valid MP2 bitrate, or 0 if invalid
static int validate_mp2_bitrate(int bitrate) {
for (int i = 0; i < sizeof(MP2_VALID_BITRATES) / sizeof(int); i++) {
if (MP2_VALID_BITRATES[i] == bitrate) {
return bitrate; // Exact match
}
}
return 0; // Invalid bitrate
}
// Which preset should I be using?
// from dataset of three videos with Q0..Q95: (real life video, low res pixel art, high res pixel art)
// 5 25 50 75 90 Claude Opus 4.1 (with data analysis)
// 10 25 45 65 85 ChatGPT-5 (without data analysis)
// 10 30 50 70 90 ChatGPT-5 (with data analysis)
static const int QUALITY_Y[] = {5, 18, 36, 54, 72, 90};
static const int QUALITY_CO[] = {5, 18, 36, 54, 72, 90};
// Encoding parameters
#define MAX_MOTION_SEARCH 16
int KEYFRAME_INTERVAL = 60;
#define BLOCK_SIZE 16 // 16x16 blocks now
#define BLOCK_SIZE_SQR 256
#define BLOCK_SIZE_SQRF 256.f
#define HALF_BLOCK_SIZE 8
#define HALF_BLOCK_SIZE_SQR 64
#define ZSTD_COMPRESSON_LEVEL 15
static float jpeg_quality_to_mult(int q) {
return ((q < 50) ? 5000.f / q : 200.f - 2*q) / 100.f;
}
// Quality settings for quantisation (Y channel) - 16x16 tables
static const uint32_t QUANT_TABLE_Y[BLOCK_SIZE_SQR] =
// Quality 50
{16, 14, 12, 11, 11, 13, 16, 20, 24, 30, 39, 48, 54, 61, 67, 73,
14, 13, 12, 12, 12, 15, 18, 21, 25, 33, 46, 57, 61, 65, 67, 70,
13, 12, 12, 13, 14, 17, 19, 23, 27, 36, 53, 66, 68, 69, 68, 67,
13, 13, 13, 14, 15, 18, 22, 26, 32, 41, 56, 67, 71, 74, 70, 67,
14, 14, 14, 15, 17, 20, 24, 30, 38, 47, 58, 68, 74, 79, 73, 67,
15, 15, 15, 17, 19, 22, 27, 34, 44, 55, 68, 79, 83, 85, 78, 70,
15, 16, 17, 20, 22, 26, 30, 38, 49, 63, 81, 94, 93, 91, 83, 74,
16, 18, 20, 24, 28, 33, 38, 47, 57, 73, 93, 108, 105, 101, 91, 81,
19, 21, 23, 29, 35, 43, 52, 60, 68, 83, 105, 121, 118, 115, 102, 89,
21, 24, 27, 35, 43, 53, 62, 70, 78, 91, 113, 128, 127, 125, 112, 99,
25, 30, 34, 43, 53, 61, 68, 76, 85, 97, 114, 127, 130, 132, 120, 108,
31, 38, 44, 54, 64, 71, 76, 84, 94, 105, 118, 129, 135, 138, 127, 116,
45, 52, 60, 69, 78, 84, 90, 97, 107, 118, 130, 139, 142, 143, 133, 122,
59, 68, 76, 84, 91, 97, 102, 110, 120, 129, 139, 147, 147, 146, 137, 127,
73, 82, 92, 98, 103, 107, 110, 117, 126, 132, 134, 136, 138, 138, 133, 127,
86, 98, 109, 112, 114, 116, 118, 124, 133, 135, 129, 125, 128, 130, 128, 127};
// Quality settings for quantisation (X channel - 8x8)
static const uint32_t QUANT_TABLE_C[HALF_BLOCK_SIZE_SQR] =
{17, 18, 24, 47, 99, 99, 99, 99,
18, 21, 26, 66, 99, 99, 99, 99,
24, 26, 56, 99, 99, 99, 99, 99,
47, 66, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99};
// Audio constants (reuse MP2 from existing system)
#define MP2_SAMPLE_RATE 32000
#define MP2_DEFAULT_PACKET_SIZE 1728
// Default values
#define DEFAULT_WIDTH 560
#define DEFAULT_HEIGHT 448
static void generate_random_filename(char *filename) {
srand(time(NULL));
const char charset[] = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
const int charset_size = sizeof(charset) - 1;
// Start with the prefix
strcpy(filename, "/tmp/");
// Generate 32 random characters
for (int i = 0; i < 32; i++) {
filename[5 + i] = charset[rand() % charset_size];
}
// Add the .mp2 extension
strcpy(filename + 37, ".mp2");
filename[41] = '\0'; // Null terminate
}
char TEMP_AUDIO_FILE[42];
typedef struct __attribute__((packed)) {
uint8_t mode; // Block encoding mode
int16_t mv_x, mv_y; // Motion vector (1/4 pixel precision)
float rate_control_factor; // Rate control factor (4 bytes, little-endian)
uint16_t cbp; // Coded block pattern (which channels have non-zero coeffs)
int16_t y_coeffs[BLOCK_SIZE_SQR]; // quantised Y DCT coefficients (16x16)
int16_t co_coeffs[HALF_BLOCK_SIZE_SQR]; // quantised Co DCT coefficients (8x8)
int16_t cg_coeffs[HALF_BLOCK_SIZE_SQR]; // quantised Cg DCT coefficients (8x8)
} tev_block_t;
// Subtitle entry structure
typedef struct subtitle_entry {
int start_frame;
int end_frame;
char *text;
struct subtitle_entry *next;
} subtitle_entry_t;
typedef struct {
char *input_file;
char *output_file;
char *subtitle_file; // SubRip (.srt) file path
int width;
int height;
int fps;
int output_fps; // User-specified output FPS (for frame rate conversion)
int total_frames;
double duration;
int has_audio;
int has_subtitles;
int output_to_stdout;
int progressive_mode; // 0 = interlaced (default), 1 = progressive
int is_ntsc_framerate; // 1 if framerate denominator is 1001, 0 otherwise
int qualityIndex; // -q option
int qualityY;
int qualityCo;
int qualityCg;
int verbose;
int disable_rcf; // 0 = rcf enabled, 1 = disabled
int ictcp_mode; // 0 = YCoCg-R (default), 1 = ICtCp colour space
// Bitrate control
int target_bitrate_kbps; // Target bitrate in kbps (0 = quality mode)
int bitrate_mode; // 0 = quality, 1 = bitrate, 2 = hybrid
float rate_control_factor; // Dynamic adjustment factor
// Frame buffers (8-bit RGB format for encoding)
uint8_t *current_rgb, *previous_rgb, *reference_rgb;
uint8_t *previous_even_field; // Previous even field buffer for interlaced scene change detection
// YCoCg workspace
float *y_workspace, *co_workspace, *cg_workspace;
float *dct_workspace; // DCT coefficients
tev_block_t *block_data; // Encoded block data
uint8_t *compressed_buffer; // Zstd output
// Audio handling
FILE *mp2_file;
int mp2_packet_size;
int mp2_rate_index;
int audio_bitrate; // Custom audio bitrate (0 = use quality table)
size_t audio_remaining;
uint8_t *mp2_buffer;
double audio_frames_in_buffer;
int target_audio_buffer_size;
// Compression context
ZSTD_CCtx *zstd_context;
// FFmpeg processes
FILE *ffmpeg_video_pipe;
// Progress tracking
struct timeval start_time;
size_t total_output_bytes;
// Statistics
int blocks_skip, blocks_intra, blocks_inter, blocks_motion;
// Rate control statistics
size_t frame_bits_accumulator;
size_t target_bits_per_frame;
float complexity_history[60]; // Rolling window for complexity
int complexity_history_index;
float average_complexity;
// Subtitle handling
subtitle_entry_t *subtitle_list;
subtitle_entry_t *current_subtitle;
// Complexity statistics collection
int stats_mode; // 0 = disabled, 1 = enabled
float *complexity_values; // Array to store all complexity values
int complexity_count; // Current count of complexity values
int complexity_capacity; // Capacity of complexity_values array
} tev_encoder_t;
//////////////////////////
// COLOUR MATHS CODES //
//////////////////////////
// RGB to YCoCg-R transform (per YCoCg-R specification with truncated division)
static void rgb_to_ycocgr(uint8_t r, uint8_t g, uint8_t b, int *y, int *co, int *cg) {
*co = (int)r - (int)b;
int tmp = (int)b + ((*co) / 2);
*cg = (int)g - tmp;
*y = tmp + ((*cg) / 2);
// Clamp to valid ranges (YCoCg-R should be roughly -256 to +255)
*y = CLAMP(*y, 0, 255);
*co = CLAMP(*co, -256, 255);
*cg = CLAMP(*cg, -256, 255);
}
// YCoCg-R to RGB transform (for verification - per YCoCg-R specification)
static void ycocgr_to_rgb(int y, int co, int cg, uint8_t *r, uint8_t *g, uint8_t *b) {
int tmp = y - (cg / 2);
*g = cg + tmp;
*b = tmp - (co / 2);
*r = *b + co;
// Clamp values
*r = CLAMP(*r, 0, 255);
*g = CLAMP(*g, 0, 255);
*b = CLAMP(*b, 0, 255);
}
// ---------------------- ICtCp Implementation ----------------------
static inline int iround(double v) { return (int)floor(v + 0.5); }
// ---------------------- sRGB gamma helpers ----------------------
static inline double srgb_linearize(double val) {
// val in [0,1]
if (val <= 0.04045) return val / 12.92;
return pow((val + 0.055) / 1.055, 2.4);
}
static inline double srgb_unlinearize(double val) {
// val in [0,1]
if (val <= 0.0031308) return val * 12.92;
return 1.055 * pow(val, 1.0 / 2.4) - 0.055;
}
// -------------------------- HLG --------------------------
// Forward HLG OETF (linear -> HLG)
static inline double HLG_OETF(double L) {
// L in [0,1], relative scene-linear
const double a = 0.17883277;
const double b = 1.0 - 4.0 * a;
const double c = 0.5 - a * log(4.0 * a);
if (L <= 1.0/12.0)
return sqrt(3.0 * L);
else
return a * log(12.0 * L - b) + c;
}
// Inverse HLG OETF (HLG -> linear)
static inline double HLG_inverse_OETF(double V) {
const double a = 0.17883277;
const double b = 1.0 - 4.0 * a;
const double c = 0.5 - a * log(4.0 * a);
if (V <= 0.5)
return (V * V) / 3.0;
else
return (exp((V - c)/a) + b) / 12.0;
}
// ---------------------- Matrices (doubles) ----------------------
// linear RGB -> XYZ -> Rec.2100 -> LMS
/*static const double M_RGB_TO_LMS[3][3] = {
{1688.0/4096.0,2146.0/4096.0, 262.0/4096.0},
{ 683.0/4096.0,2951.0/4096.0, 462.0/4096.0},
{ 99.0/4096.0, 309.0/4096.0,3688.0/4096.0}
};*/
static const double M_RGB_TO_LMS[3][3] = {
{0.2958564579364564, 0.6230869483219083, 0.08106989398623762},
{0.15627390752659093, 0.727308963512872, 0.11639736914944238},
{0.035141262332177715, 0.15657109121101628, 0.8080956851990795}
};
// Inverse: LMS -> linear sRGB (inverse of above)
/*static const double M_LMS_TO_RGB[3][3] = {
{3.436606694333079, -2.5064521186562705, 0.06984542432319149},
{-0.7913295555989289, 1.983600451792291, -0.192270896193362},
{-0.025949899690592665, -0.09891371471172647, 1.1248636144023192}
};*/
static const double M_LMS_TO_RGB[3][3] = {
{6.1723815689243215, -5.319534979827695, 0.14699442094633924},
{-1.3243428148026244, 2.560286104841917, -0.2359203727576164},
{-0.011819739235953752, -0.26473549971186555, 1.2767952602537955}
};
// ICtCp matrix (L' M' S' -> I Ct Cp). Values are the BT.2100 integer-derived /4096 constants.
static const double M_LMSPRIME_TO_ICTCP[3][3] = {
{ 2048.0/4096.0, 2048.0/4096.0, 0.0 },
{ 3625.0/4096.0, -7465.0/4096.0, 3840.0/4096.0 },
{ 9500.0/4096.0, -9212.0/4096.0, -288.0/4096.0 }
};
// Inverse: I Ct Cp -> L' M' S' (precomputed inverse)
static const double M_ICTCP_TO_LMSPRIME[3][3] = {
{ 1.0, 0.015718580108730416, 0.2095810681164055 },
{ 1.0, -0.015718580108730416, -0.20958106811640548 },
{ 1.0, 1.0212710798422344, -0.6052744909924316 }
};
// ---------------------- Forward: sRGB8 -> ICtCp (doubles) ----------------------
// Inputs: r,g,b in 0..255 sRGB (8-bit)
// Outputs: I, Ct, Cp as doubles (nominally I in ~[0..1], Ct/Cp ranges depend on colours)
void srgb8_to_ictcp_hlg(uint8_t r8, uint8_t g8, uint8_t b8,
double *out_I, double *out_Ct, double *out_Cp)
{
// 1) linearize sRGB to 0..1
double r = srgb_linearize((double)r8 / 255.0);
double g = srgb_linearize((double)g8 / 255.0);
double b = srgb_linearize((double)b8 / 255.0);
// 2) linear RGB -> LMS (single 3x3 multiply)
double L = M_RGB_TO_LMS[0][0]*r + M_RGB_TO_LMS[0][1]*g + M_RGB_TO_LMS[0][2]*b;
double M = M_RGB_TO_LMS[1][0]*r + M_RGB_TO_LMS[1][1]*g + M_RGB_TO_LMS[1][2]*b;
double S = M_RGB_TO_LMS[2][0]*r + M_RGB_TO_LMS[2][1]*g + M_RGB_TO_LMS[2][2]*b;
// 3) apply HLG encode (map linear LMS -> perceptual domain L',M',S')
double Lp = HLG_OETF(L);
double Mp = HLG_OETF(M);
double Sp = HLG_OETF(S);
// 4) L'M'S' -> ICtCp
double I = M_LMSPRIME_TO_ICTCP[0][0]*Lp + M_LMSPRIME_TO_ICTCP[0][1]*Mp + M_LMSPRIME_TO_ICTCP[0][2]*Sp;
double Ct = M_LMSPRIME_TO_ICTCP[1][0]*Lp + M_LMSPRIME_TO_ICTCP[1][1]*Mp + M_LMSPRIME_TO_ICTCP[1][2]*Sp;
double Cp = M_LMSPRIME_TO_ICTCP[2][0]*Lp + M_LMSPRIME_TO_ICTCP[2][1]*Mp + M_LMSPRIME_TO_ICTCP[2][2]*Sp;
*out_I = FCLAMP(I * 255.f, 0.f, 255.f);
*out_Ct = FCLAMP(Ct * 255.f, -256.f, 255.f);
*out_Cp = FCLAMP(Cp * 255.f, -256.f, 255.f);
}
// ---------------------- Reverse: ICtCp -> sRGB8 (doubles) ----------------------
// Inputs: I, Ct, Cp as doubles
// Outputs: r8,g8,b8 in 0..255 (8-bit sRGB, clamped and rounded)
void ictcp_hlg_to_srgb8(double I8, double Ct8, double Cp8,
uint8_t *r8, uint8_t *g8, uint8_t *b8)
{
double I = I8 / 255.f;
double Ct = Ct8 / 255.f;
double Cp = Cp8 / 255.f;
// 1) ICtCp -> L' M' S' (3x3 multiply)
double Lp = M_ICTCP_TO_LMSPRIME[0][0]*I + M_ICTCP_TO_LMSPRIME[0][1]*Ct + M_ICTCP_TO_LMSPRIME[0][2]*Cp;
double Mp = M_ICTCP_TO_LMSPRIME[1][0]*I + M_ICTCP_TO_LMSPRIME[1][1]*Ct + M_ICTCP_TO_LMSPRIME[1][2]*Cp;
double Sp = M_ICTCP_TO_LMSPRIME[2][0]*I + M_ICTCP_TO_LMSPRIME[2][1]*Ct + M_ICTCP_TO_LMSPRIME[2][2]*Cp;
// 2) HLG decode: L' -> linear LMS
double L = HLG_inverse_OETF(Lp);
double M = HLG_inverse_OETF(Mp);
double S = HLG_inverse_OETF(Sp);
// 3) LMS -> linear sRGB (3x3 inverse)
double r_lin = M_LMS_TO_RGB[0][0]*L + M_LMS_TO_RGB[0][1]*M + M_LMS_TO_RGB[0][2]*S;
double g_lin = M_LMS_TO_RGB[1][0]*L + M_LMS_TO_RGB[1][1]*M + M_LMS_TO_RGB[1][2]*S;
double b_lin = M_LMS_TO_RGB[2][0]*L + M_LMS_TO_RGB[2][1]*M + M_LMS_TO_RGB[2][2]*S;
// 4) gamma encode and convert to 0..255 with center-of-bin rounding
double r = srgb_unlinearize(r_lin);
double g = srgb_unlinearize(g_lin);
double b = srgb_unlinearize(b_lin);
*r8 = (uint8_t)CLAMP(iround(r * 255.0), 0, 255);
*g8 = (uint8_t)CLAMP(iround(g * 255.0), 0, 255);
*b8 = (uint8_t)CLAMP(iround(b * 255.0), 0, 255);
}
// ---------------------- Color Space Switching Functions ----------------------
// Wrapper functions that choose between YCoCg-R and ICtCp based on encoder mode
static void rgb_to_colour_space(tev_encoder_t *enc, uint8_t r, uint8_t g, uint8_t b,
double *c1, double *c2, double *c3) {
if (enc->ictcp_mode) {
// Use ICtCp colour space
srgb8_to_ictcp_hlg(r, g, b, c1, c2, c3);
} else {
// Use YCoCg-R colour space (convert to int first, then to double)
int y_val, co_val, cg_val;
rgb_to_ycocgr(r, g, b, &y_val, &co_val, &cg_val);
*c1 = (double)y_val;
*c2 = (double)co_val;
*c3 = (double)cg_val;
}
}
static void colour_space_to_rgb(tev_encoder_t *enc, double c1, double c2, double c3,
uint8_t *r, uint8_t *g, uint8_t *b) {
if (enc->ictcp_mode) {
// Use ICtCp colour space
ictcp_hlg_to_srgb8(c1, c2, c3, r, g, b);
} else {
// Use YCoCg-R colour space (convert from double to int first)
int y_val = (int)round(c1);
int co_val = (int)round(c2);
int cg_val = (int)round(c3);
ycocgr_to_rgb(y_val, co_val, cg_val, r, g, b);
}
}
////////////////////////////////////////
// DISCRETE COSINE TRANSFORMATIONS //
////////////////////////////////////////
// Pre-calculated cosine tables
static float dct_table_16[16][16]; // For 16x16 DCT
static float dct_table_8[8][8]; // For 8x8 DCT
static int tables_initialised = 0;
// Initialise the pre-calculated tables
static void init_dct_tables(void) {
if (tables_initialised) return;
// Pre-calculate cosine values for 16x16 DCT
for (int u = 0; u < 16; u++) {
for (int x = 0; x < 16; x++) {
dct_table_16[u][x] = cosf((2.0f * x + 1.0f) * u * M_PI / 32.0f);
}
}
// Pre-calculate cosine values for 8x8 DCT
for (int u = 0; u < 8; u++) {
for (int x = 0; x < 8; x++) {
dct_table_8[u][x] = cosf((2.0f * x + 1.0f) * u * M_PI / 16.0f);
}
}
tables_initialised = 1;
}
// 16x16 2D DCT
// Fast separable 16x16 DCT - 8x performance improvement
static float temp_dct_16[BLOCK_SIZE_SQR]; // Reusable temporary buffer
static void dct_16x16_fast(float *input, float *output) {
init_dct_tables(); // Ensure tables are initialised
// First pass: Process rows (16 1D DCTs)
for (int row = 0; row < 16; row++) {
for (int u = 0; u < 16; u++) {
float sum = 0.0f;
float cu = (u == 0) ? 1.0f / sqrtf(2.0f) : 1.0f;
for (int x = 0; x < 16; x++) {
sum += input[row * 16 + x] * dct_table_16[u][x];
}
temp_dct_16[row * 16 + u] = 0.5f * cu * sum;
}
}
// Second pass: Process columns (16 1D DCTs)
for (int col = 0; col < 16; col++) {
for (int v = 0; v < 16; v++) {
float sum = 0.0f;
float cv = (v == 0) ? 1.0f / sqrtf(2.0f) : 1.0f;
for (int y = 0; y < 16; y++) {
sum += temp_dct_16[y * 16 + col] * dct_table_16[v][y];
}
output[v * 16 + col] = 0.5f * cv * sum;
}
}
}
// Fast separable 8x8 DCT - 4x performance improvement
static float temp_dct_8[HALF_BLOCK_SIZE_SQR]; // Reusable temporary buffer
static void dct_8x8_fast(float *input, float *output) {
init_dct_tables(); // Ensure tables are initialised
// First pass: Process rows (8 1D DCTs)
for (int row = 0; row < 8; row++) {
for (int u = 0; u < 8; u++) {
float sum = 0.0f;
float cu = (u == 0) ? 1.0f / sqrtf(2.0f) : 1.0f;
for (int x = 0; x < 8; x++) {
sum += input[row * 8 + x] * dct_table_8[u][x];
}
temp_dct_8[row * 8 + u] = 0.5f * cu * sum;
}
}
// Second pass: Process columns (8 1D DCTs)
for (int col = 0; col < 8; col++) {
for (int v = 0; v < 8; v++) {
float sum = 0.0f;
float cv = (v == 0) ? 1.0f / sqrtf(2.0f) : 1.0f;
for (int y = 0; y < 8; y++) {
sum += temp_dct_8[y * 8 + col] * dct_table_8[v][y];
}
output[v * 8 + col] = 0.5f * cv * sum;
}
}
}
// quantise DCT coefficient using quality table with rate control
static int16_t quantise_coeff(float coeff, float quant, int is_dc, int is_chroma) {
if (is_dc) {
if (is_chroma) {
// Chroma DC: range -256 to +255, use lossless quantisation for testing
return (int16_t)roundf(coeff);
} else {
// Luma DC: range -128 to +127, use lossless quantisation for testing
return (int16_t)roundf(coeff);
}
} else {
// AC coefficients use quality table (rate control factor applied to quant table before calling)
float safe_quant = fmaxf(quant, 1.0f); // Prevent division by zero
return (int16_t)roundf(coeff / safe_quant);
}
}
// Extract 16x16 block from RGB frame and convert to colour space
static void extract_colour_space_block(tev_encoder_t *enc, uint8_t *rgb_frame, int width, int height,
int block_x, int block_y,
float *c1_block, float *c2_block, float *c3_block) {
int start_x = block_x * BLOCK_SIZE;
int start_y = block_y * BLOCK_SIZE;
// Extract 16x16 primary channel block (Y for YCoCg-R, I for ICtCp)
for (int py = 0; py < BLOCK_SIZE; py++) {
for (int px = 0; px < BLOCK_SIZE; px++) {
int x = start_x + px;
int y = start_y + py;
if (x < width && y < height) {
int offset = (y * width + x) * 3;
uint8_t r = rgb_frame[offset];
uint8_t g = rgb_frame[offset + 1];
uint8_t b = rgb_frame[offset + 2];
double c1, c2, c3;
rgb_to_colour_space(enc, r, g, b, &c1, &c2, &c3);
c1_block[py * BLOCK_SIZE + px] = (float)c1 - 128.0f;
}
}
}
// Extract 8x8 chroma blocks with 4:2:0 subsampling (average 2x2 pixels)
for (int py = 0; py < HALF_BLOCK_SIZE; py++) {
for (int px = 0; px < HALF_BLOCK_SIZE; px++) {
int co_sum = 0, cg_sum = 0, count = 0;
// Average 2x2 block of pixels
for (int dy = 0; dy < 2; dy++) {
for (int dx = 0; dx < 2; dx++) {
int x = start_x + px * 2 + dx;
int y = start_y + py * 2 + dy;
if (x < width && y < height) {
int offset = (y * width + x) * 3;
uint8_t r = rgb_frame[offset];
uint8_t g = rgb_frame[offset + 1];
uint8_t b = rgb_frame[offset + 2];
double c1, c2, c3;
rgb_to_colour_space(enc, r, g, b, &c1, &c2, &c3);
co_sum += (int)c2;
cg_sum += (int)c3;
count++;
}
}
}
if (count > 0) {
// Average the accumulated chroma values and store
c2_block[py * HALF_BLOCK_SIZE + px] = (float)(co_sum / count);
c3_block[py * HALF_BLOCK_SIZE + px] = (float)(cg_sum / count);
}
}
}
}
// Calculate spatial activity for any channel (16x16 or 8x8)
static float calculate_spatial_activity(const float *block, int block_size) {
float activity = 0.0f;
// Sum of absolute differences with neighbors (spatial activity)
for (int y = 0; y < block_size; y++) {
for (int x = 0; x < block_size; x++) {
float pixel = block[y * block_size + x];
// Compare with right neighbor
if (x < block_size - 1) {
activity += fabsf(pixel - block[y * block_size + (x + 1)]);
}
// Compare with bottom neighbor
if (y < block_size - 1) {
activity += fabsf(pixel - block[(y + 1) * block_size + x]);
}
}
}
return activity;
}
// Calculate variance for any channel
static float calculate_variance(const float *block, int block_size) {
int total_pixels = block_size * block_size;
// Calculate mean
float mean = 0.0f;
for (int i = 0; i < total_pixels; i++) {
mean += block[i];
}
mean /= total_pixels;
// Calculate variance
float variance = 0.0f;
for (int i = 0; i < total_pixels; i++) {
float diff = block[i] - mean;
variance += diff * diff;
}
variance /= total_pixels;
return variance;
}
// Enhanced block complexity calculation including chroma information
static float calculate_block_complexity_enhanced(const float *y_block, const float *co_block, const float *cg_block) {
// Luma complexity (16x16)
float luma_activity = calculate_spatial_activity(y_block, BLOCK_SIZE);
float luma_variance = calculate_variance(y_block, BLOCK_SIZE);
float luma_complexity = luma_activity + sqrtf(luma_variance) * 10.0f;
// Chroma complexity (8x8 blocks, but weighted appropriately)
float co_activity = calculate_spatial_activity(co_block, HALF_BLOCK_SIZE);
float co_variance = calculate_variance(co_block, HALF_BLOCK_SIZE);
float co_complexity = co_activity + sqrtf(co_variance) * 10.0f;
float cg_activity = calculate_spatial_activity(cg_block, HALF_BLOCK_SIZE);
float cg_variance = calculate_variance(cg_block, HALF_BLOCK_SIZE);
float cg_complexity = cg_activity + sqrtf(cg_variance) * 10.0f;
// Combine complexities with appropriate weighting
// Luma gets primary weight, chroma gets secondary weight but significant enough to matter
// Scale chroma by 4 to account for 8x8 vs 16x16 size difference (64 vs 256 pixels)
float total_complexity = luma_complexity +
(co_complexity * 4.0f * 0.3f) +
(cg_complexity * 4.0f * 0.3f);
return total_complexity;
}
// Legacy function for compatibility - calls enhanced version
static float calculate_block_complexity(const float *y_block) {
float complexity = 0.0f;
// Method 1: Sum of absolute differences with neighbors (spatial activity)
for (int y = 0; y < BLOCK_SIZE; y++) {
for (int x = 0; x < BLOCK_SIZE; x++) {
float pixel = y_block[y * BLOCK_SIZE + x];
// Compare with right neighbor
if (x < BLOCK_SIZE - 1) {
complexity += fabsf(pixel - y_block[y * BLOCK_SIZE + (x + 1)]);
}
// Compare with bottom neighbor
if (y < BLOCK_SIZE - 1) {
complexity += fabsf(pixel - y_block[(y + 1) * BLOCK_SIZE + x]);
}
}
}
// Method 2: Add variance contribution
float mean = 0.0f;
for (int i = 0; i < BLOCK_SIZE_SQR; i++) {
mean += y_block[i];
}
mean /= BLOCK_SIZE_SQRF;
float variance = 0.0f;
for (int i = 0; i < BLOCK_SIZE_SQR; i++) {
float diff = y_block[i] - mean;
variance += diff * diff;
}
variance /= BLOCK_SIZE_SQRF;
// Combine spatial activity and variance
return complexity + sqrtf(variance) * 10.0f;
}
// Map complexity to rate control factor (pure per-block, no global factor)
// Data-driven approach: rate_control_factor multiplies reconstructed coefficients in decoder
// Higher factor = more detail preserved, lower factor = acceptable quality loss
static float complexity_to_rate_factor(float complexity) {
// Handle zero/near-zero complexity (very common in sample data)
if (complexity <= 0.001f) {
return 0.7f; // Reduce detail for flat blocks (saves bits, minimal perceptual loss)
}
// Parameters recalibrated for chroma-aware complexity calculation:
// - Median complexity now ~1400-3700 (increased due to chroma contribution)
// - High complexity threshold ~10000-15000 (91st percentile)
// - Maximum values up to ~22800 (vs ~17000 in luma-only version)
const float median_complexity = 4447.0f; // Target for rate_factor ≈ 1.0. e^8.4
const float high_complexity = 12088.0f; // ~91st percentile threshold. e^9.4
// Logarithmic preprocessing to handle wide dynamic range (0 to 23000+)
float log_complexity = logf(complexity + 1.0f);
float log_median = logf(median_complexity + 1.0f);
float log_high = logf(high_complexity + 1.0f);
// Normalise: 0 = median complexity, 1 = high complexity threshold
float normalised = (log_complexity - log_median) / (log_high - log_median);
// Sigmoid centered at median: f(0) ≈ 1.0, f(1) ≈ 1.6, f(-∞) ≈ 0.7
float sigmoid = 1.0f / (1.0f + expf(-4.0f * normalised));
float rate_factor = 0.7f + 0.9f * sigmoid; // Range: 0.7 to 1.6
// Clamp to prevent extreme coefficient amplification/reduction
return FCLAMP(rate_factor, 0.7f, 1.6f);
// See also: https://www.desmos.com/calculator/awwjztvv3o
}
// Add complexity value to statistics collection
static void add_complexity_value(tev_encoder_t *enc, float complexity) {
if (!enc->stats_mode) return;
// Initialise array if needed
if (!enc->complexity_values) {
enc->complexity_capacity = 10000; // Initial capacity
enc->complexity_values = malloc(enc->complexity_capacity * sizeof(float));
if (!enc->complexity_values) {
fprintf(stderr, "Warning: Failed to allocate complexity statistics array\n");
enc->stats_mode = 0;
return;
}
enc->complexity_count = 0;
}
// Resize array if needed
if (enc->complexity_count >= enc->complexity_capacity) {
enc->complexity_capacity *= 2;
float *new_array = realloc(enc->complexity_values, enc->complexity_capacity * sizeof(float));
if (!new_array) {
fprintf(stderr, "Warning: Failed to resize complexity statistics array\n");
return;
}
enc->complexity_values = new_array;
}
enc->complexity_values[enc->complexity_count++] = complexity;
}
// Comparison function for qsort
static int compare_float(const void *a, const void *b) {
float fa = *(const float*)a;
float fb = *(const float*)b;
if (fa < fb) return -1;
if (fa > fb) return 1;
return 0;
}
// Calculate seven-number summary statistics
static void calculate_complexity_stats(tev_encoder_t *enc) {
if (!enc->stats_mode || enc->complexity_count == 0) return;
printf("\n=== BLOCK COMPLEXITY STATISTICS ===\n");
printf("Analysed %d blocks during encoding\n\n", enc->complexity_count);
// Sort the values to calculate percentiles
float *sorted_values = malloc(enc->complexity_count * sizeof(float));
if (!sorted_values) {
fprintf(stderr, "Failed to allocate memory for statistics calculation\n");
return;
}
memcpy(sorted_values, enc->complexity_values, enc->complexity_count * sizeof(float));
qsort(sorted_values, enc->complexity_count, sizeof(float), compare_float);
// Calculate seven-number summary percentiles: 2.15%, 8.87%, 25%, 50%, 75%, 91.13%, 97.85%
float p2_15 = sorted_values[(int)(0.0215 * (enc->complexity_count - 1))];
float p8_87 = sorted_values[(int)(0.0887 * (enc->complexity_count - 1))];
float p25 = sorted_values[(int)(0.25 * (enc->complexity_count - 1))];
float p50 = sorted_values[(int)(0.50 * (enc->complexity_count - 1))];
float p75 = sorted_values[(int)(0.75 * (enc->complexity_count - 1))];
float p91_13 = sorted_values[(int)(0.9113 * (enc->complexity_count - 1))];
float p97_85 = sorted_values[(int)(0.9785 * (enc->complexity_count - 1))];
// Print human-readable format
printf("Seven-Number Summary:\n");
printf(" 2.15%% percentile: %.6f\n", p2_15);
printf(" 8.87%% percentile: %.6f\n", p8_87);
printf(" 25.0%% percentile: %.6f\n", p25);
printf(" 50.0%% percentile: %.6f\n", p50);
printf(" 75.0%% percentile: %.6f\n", p75);
printf(" 91.13%% percentile: %.6f\n", p91_13);
printf(" 97.85%% percentile: %.6f\n", p97_85);
// Print CSV format for copy-pasting
printf("CSV Format (copy-pastable):\n");
printf("2.15%%,8.87%%,25.0%%,50.0%%,75.0%%,91.13%%,97.85%%\n");
printf("%.6f,%.6f,%.6f,%.6f,%.6f,%.6f,%.6f\n", p2_15, p8_87, p25, p50, p75, p91_13, p97_85);
free(sorted_values);
printf("=====================================\n");
}
// Simple motion estimation (full search) for 16x16 blocks
static void estimate_motion(tev_encoder_t *enc, int block_x, int block_y,
int16_t *best_mv_x, int16_t *best_mv_y) {
int best_sad = INT_MAX;
*best_mv_x = 0;
*best_mv_y = 0;
int start_x = block_x * BLOCK_SIZE;
int start_y = block_y * BLOCK_SIZE;
// Diamond search pattern (much faster than full search)
static const int diamond_x[] = {0, -1, 1, 0, 0, -2, 2, 0, 0};
static const int diamond_y[] = {0, 0, 0, -1, 1, 0, 0, -2, 2};
int center_x = 0, center_y = 0;
int step_size = 4; // Start with larger steps
while (step_size >= 1) {
int improved = 0;
for (int i = 0; i < 9; i++) {
int mv_x = center_x + diamond_x[i] * step_size;
int mv_y = center_y + diamond_y[i] * step_size;
// Check bounds
if (mv_x < -MAX_MOTION_SEARCH || mv_x > MAX_MOTION_SEARCH ||
mv_y < -MAX_MOTION_SEARCH || mv_y > MAX_MOTION_SEARCH) {
continue;
}
int ref_x = start_x - mv_x;
int ref_y = start_y - mv_y;
if (ref_x < 0 || ref_y < 0 ||
ref_x + BLOCK_SIZE > enc->width || ref_y + BLOCK_SIZE > enc->height) {
continue;
}
// Fast SAD using integer luma approximation
int sad = 0;
for (int dy = 0; dy < BLOCK_SIZE; dy += 2) { // Sample every 2nd row for speed
uint8_t *cur_row = &enc->current_rgb[((start_y + dy) * enc->width + start_x) * 3];
uint8_t *ref_row = &enc->previous_rgb[((ref_y + dy) * enc->width + ref_x) * 3];
for (int dx = 0; dx < BLOCK_SIZE; dx += 2) { // Sample every 2nd pixel
// Fast luma approximation: (R + 2*G + B) >> 2
int cur_luma = (cur_row[dx*3] + (cur_row[dx*3+1] << 1) + cur_row[dx*3+2]) >> 2;
int ref_luma = (ref_row[dx*3] + (ref_row[dx*3+1] << 1) + ref_row[dx*3+2]) >> 2;
sad += abs(cur_luma - ref_luma);
}
}
if (sad < best_sad) {
best_sad = sad;
*best_mv_x = mv_x;
*best_mv_y = mv_y;
center_x = mv_x;
center_y = mv_y;
improved = 1;
}
}
if (!improved) {
step_size >>= 1; // Reduce step size
}
}
}
// Convert RGB block to YCoCg-R with 4:2:0 chroma subsampling
static void convert_rgb_to_colour_space_block(tev_encoder_t *enc, const uint8_t *rgb_block,
float *c1_workspace, float *c2_workspace, float *c3_workspace) {
if (enc->ictcp_mode) {
// ICtCp mode: Convert 16x16 RGB to ICtCp (full resolution for I, 4:2:0 subsampling for CtCp)
// Convert I channel at full resolution (16x16)
for (int py = 0; py < BLOCK_SIZE; py++) {
for (int px = 0; px < BLOCK_SIZE; px++) {
int rgb_idx = (py * BLOCK_SIZE + px) * 3;
uint8_t r = rgb_block[rgb_idx];
uint8_t g = rgb_block[rgb_idx + 1];
uint8_t b = rgb_block[rgb_idx + 2];
double I, Ct, Cp;
srgb8_to_ictcp_hlg(r, g, b, &I, &Ct, &Cp);
// Store I at full resolution, scale to appropriate range
c1_workspace[py * BLOCK_SIZE + px] = (float)(I * 255.0);
}
}
// Convert Ct and Cp with 4:2:0 subsampling (8x8)
for (int cy = 0; cy < HALF_BLOCK_SIZE; cy++) {
for (int cx = 0; cx < HALF_BLOCK_SIZE; cx++) {
double sum_ct = 0.0, sum_cp = 0.0;
// Sample 2x2 block from RGB and average for chroma
for (int dy = 0; dy < 2; dy++) {
for (int dx = 0; dx < 2; dx++) {
int py = cy * 2 + dy;
int px = cx * 2 + dx;
int rgb_idx = (py * 16 + px) * 3;
int r = rgb_block[rgb_idx];
int g = rgb_block[rgb_idx + 1];
int b = rgb_block[rgb_idx + 2];
double I, Ct, Cp;
srgb8_to_ictcp_hlg(r, g, b, &I, &Ct, &Cp);
sum_ct += Ct;
sum_cp += Cp;
}
}
// Average and store subsampled chroma, scale to signed 8-bit equivalent range
// Apply centering to ensure chroma is balanced around 0 (like YCoCg-R)
double avg_ct = sum_ct / 4.0;
double avg_cp = sum_cp / 4.0;
// Scale and clamp to [-256, 255] range like YCoCg-R
c2_workspace[cy * HALF_BLOCK_SIZE + cx] = (float)CLAMP(avg_ct * 255.0, -256, 255);
c3_workspace[cy * HALF_BLOCK_SIZE + cx] = (float)CLAMP(avg_cp * 255.0, -256, 255);
}
}
} else {
// YCoCg-R mode: Original implementation
// Convert 16x16 RGB to Y (full resolution)
for (int py = 0; py < BLOCK_SIZE; py++) {
for (int px = 0; px < BLOCK_SIZE; px++) {
int rgb_idx = (py * BLOCK_SIZE + px) * 3;
int r = rgb_block[rgb_idx];
int g = rgb_block[rgb_idx + 1];
int b = rgb_block[rgb_idx + 2];
// YCoCg-R transform (per specification with truncated division)
int y = (r + 2*g + b) / 4;
c1_workspace[py * BLOCK_SIZE + px] = (float)CLAMP(y, 0, 255);
}
}
// Convert to Co and Cg with 4:2:0 subsampling (8x8)
for (int cy = 0; cy < HALF_BLOCK_SIZE; cy++) {
for (int cx = 0; cx < HALF_BLOCK_SIZE; cx++) {
int sum_co = 0, sum_cg = 0;
// Sample 2x2 block from RGB and average for chroma
for (int dy = 0; dy < 2; dy++) {
for (int dx = 0; dx < 2; dx++) {
int py = cy * 2 + dy;
int px = cx * 2 + dx;
int rgb_idx = (py * 16 + px) * 3;
int r = rgb_block[rgb_idx];
int g = rgb_block[rgb_idx + 1];
int b = rgb_block[rgb_idx + 2];
int co = r - b;
int tmp = b + (co / 2);
int cg = g - tmp;
sum_co += co;
sum_cg += cg;
}
}
// Average and store subsampled chroma
c2_workspace[cy * HALF_BLOCK_SIZE + cx] = (float)CLAMP(sum_co / 4, -256, 255);
c3_workspace[cy * HALF_BLOCK_SIZE + cx] = (float)CLAMP(sum_cg / 4, -256, 255);
}
}
}
}
// Extract motion-compensated YCoCg-R block from reference frame
static void extract_motion_compensated_block(const uint8_t *rgb_data, int width, int height,
int block_x, int block_y, int mv_x, int mv_y,
uint8_t *y_block, int8_t *co_block, int8_t *cg_block) {
// Extract 16x16 RGB block with motion compensation
uint8_t rgb_block[BLOCK_SIZE * BLOCK_SIZE * 3];
for (int dy = 0; dy < BLOCK_SIZE; dy++) {
for (int dx = 0; dx < BLOCK_SIZE; dx++) {
int cur_x = block_x + dx;
int cur_y = block_y + dy;
int ref_x = cur_x + mv_x; // Revert to original motion compensation
int ref_y = cur_y + mv_y;
int rgb_idx = (dy * BLOCK_SIZE + dx) * 3;
if (ref_x >= 0 && ref_y >= 0 && ref_x < width && ref_y < height) {
// Copy RGB from reference position
int ref_offset = (ref_y * width + ref_x) * 3;
rgb_block[rgb_idx] = rgb_data[ref_offset]; // R
rgb_block[rgb_idx + 1] = rgb_data[ref_offset + 1]; // G
rgb_block[rgb_idx + 2] = rgb_data[ref_offset + 2]; // B
} else {
// Out of bounds - use black
rgb_block[rgb_idx] = 0; // R
rgb_block[rgb_idx + 1] = 0; // G
rgb_block[rgb_idx + 2] = 0; // B
}
}
}
// Convert RGB block to YCoCg-R (original implementation for motion compensation)
// Convert 16x16 RGB to Y (full resolution)
for (int py = 0; py < BLOCK_SIZE; py++) {
for (int px = 0; px < BLOCK_SIZE; px++) {
int rgb_idx = (py * BLOCK_SIZE + px) * 3;
int r = rgb_block[rgb_idx];
int g = rgb_block[rgb_idx + 1];
int b = rgb_block[rgb_idx + 2];
// YCoCg-R transform (per specification with truncated division)
int y = (r + 2*g + b) / 4;
y_block[py * 16 + px] = CLAMP(y, 0, 255);
}
}
// Convert to Co and Cg with 4:2:0 subsampling (8x8)
for (int cy = 0; cy < HALF_BLOCK_SIZE; cy++) {
for (int cx = 0; cx < HALF_BLOCK_SIZE; cx++) {
// Sample 2x2 block from RGB and average for chroma
int sum_co = 0, sum_cg = 0;
for (int dy = 0; dy < 2; dy++) {
for (int dx = 0; dx < 2; dx++) {
int py = cy * 2 + dy;
int px = cx * 2 + dx;
int rgb_idx = (py * 16 + px) * 3;
int r = rgb_block[rgb_idx];
int g = rgb_block[rgb_idx + 1];
int b = rgb_block[rgb_idx + 2];
int co = r - b;
int tmp = b + (co / 2);
int cg = g - tmp;
sum_co += co;
sum_cg += cg;
}
}
// Average and store subsampled chroma
co_block[cy * HALF_BLOCK_SIZE + cx] = CLAMP(sum_co / 4, -256, 255);
cg_block[cy * HALF_BLOCK_SIZE + cx] = CLAMP(sum_cg / 4, -256, 255);
}
}
}
// Compute motion-compensated residual for INTER mode
static void compute_motion_residual(tev_encoder_t *enc, int block_x, int block_y, int mv_x, int mv_y) {
int start_x = block_x * BLOCK_SIZE;
int start_y = block_y * BLOCK_SIZE;
// Extract motion-compensated reference block from previous frame
uint8_t ref_y[BLOCK_SIZE_SQR];
int8_t ref_co[HALF_BLOCK_SIZE_SQR], ref_cg[HALF_BLOCK_SIZE_SQR];
extract_motion_compensated_block(enc->previous_rgb, enc->width, enc->height,
start_x, start_y, mv_x, mv_y,
ref_y, ref_co, ref_cg);
// Compute residuals: current - motion_compensated_reference
// Current is already centered (-128 to +127), reference is 0-255, so subtract and center reference
for (int i = 0; i < BLOCK_SIZE_SQR; i++) {
float ref_y_centered = (float)ref_y[i] - 128.0f; // Center reference to match current
enc->y_workspace[i] = enc->y_workspace[i] - ref_y_centered;
}
// Chroma residuals (already centered in both current and reference)
for (int i = 0; i < HALF_BLOCK_SIZE_SQR; i++) {
enc->co_workspace[i] = enc->co_workspace[i] - (float)ref_co[i];
enc->cg_workspace[i] = enc->cg_workspace[i] - (float)ref_cg[i];
}
}
// Calculate block complexity for rate control
// Encode a 16x16 block
static void encode_block(tev_encoder_t *enc, int block_x, int block_y, int is_keyframe) {
tev_block_t *block = &enc->block_data[block_y * ((enc->width + 15) / 16) + block_x];
// Extract YCoCg-R block
extract_colour_space_block(enc, enc->current_rgb, enc->width, enc->height,
block_x, block_y,
enc->y_workspace, enc->co_workspace, enc->cg_workspace);
if (is_keyframe) {
// Intra coding for keyframes
block->mode = TEV_MODE_INTRA;
block->mv_x = block->mv_y = 0;
enc->blocks_intra++;
} else {
// Implement proper mode decision for P-frames
int start_x = block_x * BLOCK_SIZE;
int start_y = block_y * BLOCK_SIZE;
// Calculate SAD for skip mode (no motion compensation)
int skip_sad = 0;
int skip_colour_diff = 0;
for (int dy = 0; dy < BLOCK_SIZE; dy++) {
for (int dx = 0; dx < BLOCK_SIZE; dx++) {
int x = start_x + dx;
int y = start_y + dy;
if (x < enc->width && y < enc->height) {
int cur_offset = (y * enc->width + x) * 3;
// Compare current with previous frame (using YCoCg-R Luma calculation)
int cur_luma = (enc->current_rgb[cur_offset] +
2 * enc->current_rgb[cur_offset + 1] +
enc->current_rgb[cur_offset + 2]) / 4;
int prev_luma = (enc->previous_rgb[cur_offset] +
2 * enc->previous_rgb[cur_offset + 1] +
enc->previous_rgb[cur_offset + 2]) / 4;
skip_sad += abs(cur_luma - prev_luma);
// Also check for colour differences to prevent SKIP on colour changes
int cur_r = enc->current_rgb[cur_offset];
int cur_g = enc->current_rgb[cur_offset + 1];
int cur_b = enc->current_rgb[cur_offset + 2];
int prev_r = enc->previous_rgb[cur_offset];
int prev_g = enc->previous_rgb[cur_offset + 1];
int prev_b = enc->previous_rgb[cur_offset + 2];
skip_colour_diff += abs(cur_r - prev_r) + abs(cur_g - prev_g) + abs(cur_b - prev_b);
}
}
}
// Try motion estimation
estimate_motion(enc, block_x, block_y, &block->mv_x, &block->mv_y);
// Calculate motion compensation SAD
int motion_sad = INT_MAX;
if (abs(block->mv_x) > 0 || abs(block->mv_y) > 0) {
motion_sad = 0;
for (int dy = 0; dy < BLOCK_SIZE; dy++) {
for (int dx = 0; dx < BLOCK_SIZE; dx++) {
int cur_x = start_x + dx;
int cur_y = start_y + dy;
int ref_x = cur_x + block->mv_x;
int ref_y = cur_y + block->mv_y;
if (cur_x < enc->width && cur_y < enc->height &&
ref_x >= 0 && ref_y >= 0 &&
ref_x < enc->width && ref_y < enc->height) {
int cur_offset = (cur_y * enc->width + cur_x) * 3;
int ref_offset = (ref_y * enc->width + ref_x) * 3;
// use YCoCg-R Luma calculation
int cur_luma = (enc->current_rgb[cur_offset] +
2 * enc->current_rgb[cur_offset + 1] +
enc->current_rgb[cur_offset + 2]) / 4;
int ref_luma = (enc->previous_rgb[ref_offset] +
2 * enc->previous_rgb[ref_offset + 1] +
enc->previous_rgb[ref_offset + 2]) / 4;
motion_sad += abs(cur_luma - ref_luma);
} else {
motion_sad += 128; // Penalty for out-of-bounds
}
}
}
}
// Mode decision with strict thresholds for quality
// Require both low luma difference AND low colour difference for SKIP
if (skip_sad <= 64 && skip_colour_diff <= 192) {
// Very small difference - skip block (copy from previous frame)
block->mode = TEV_MODE_SKIP;
block->mv_x = 0;
block->mv_y = 0;
// Even skip blocks benefit from complexity analysis for consistency
float block_complexity = calculate_block_complexity_enhanced(enc->y_workspace, enc->co_workspace, enc->cg_workspace);
add_complexity_value(enc, block_complexity);
block->rate_control_factor = (enc->disable_rcf) ? 1.f : complexity_to_rate_factor(block_complexity);
block->cbp = 0x00; // No coefficients present
// Zero out DCT coefficients for consistent format
memset(block->y_coeffs, 0, sizeof(block->y_coeffs));
memset(block->co_coeffs, 0, sizeof(block->co_coeffs));
memset(block->cg_coeffs, 0, sizeof(block->cg_coeffs));
enc->blocks_skip++;
return; // Skip DCT encoding entirely
} else if (motion_sad < skip_sad && motion_sad <= 1024 &&
(abs(block->mv_x) > 0 || abs(block->mv_y) > 0)) {
// Good motion prediction - use motion-only mode
block->mode = TEV_MODE_MOTION;
// Analyse complexity for motion blocks too
float block_complexity = calculate_block_complexity_enhanced(enc->y_workspace, enc->co_workspace, enc->cg_workspace);
add_complexity_value(enc, block_complexity);
block->rate_control_factor = (enc->disable_rcf) ? 1.f : complexity_to_rate_factor(block_complexity);
block->cbp = 0x00; // No coefficients present
// Zero out DCT coefficients for consistent format
memset(block->y_coeffs, 0, sizeof(block->y_coeffs));
memset(block->co_coeffs, 0, sizeof(block->co_coeffs));
memset(block->cg_coeffs, 0, sizeof(block->cg_coeffs));
enc->blocks_motion++;
return; // Skip DCT encoding, just store motion vector
// disabling INTER mode: residual DCT is crapping out no matter what I do
} /*else if (motion_sad < skip_sad && (abs(block->mv_x) > 0 || abs(block->mv_y) > 0)) {
// Motion compensation with threshold
if (motion_sad <= 1024) {
block->mode = TEV_MODE_MOTION;
block->cbp = 0x00; // No coefficients present
memset(block->y_coeffs, 0, sizeof(block->y_coeffs));
memset(block->co_coeffs, 0, sizeof(block->co_coeffs));
memset(block->cg_coeffs, 0, sizeof(block->cg_coeffs));
enc->blocks_motion++;
return; // Skip DCT encoding, just store motion vector
}
// Use INTER mode with motion vector and residuals
if (abs(block->mv_x) < BLOCK_SIZE && abs(block->mv_y) < BLOCK_SIZE) {
block->mode = TEV_MODE_INTER;
enc->blocks_inter++;
} else {
// Motion vector too large, fall back to INTRA
block->mode = TEV_MODE_INTRA;
block->mv_x = 0;
block->mv_y = 0;
enc->blocks_intra++;
}
}*/ else {
// No good motion prediction - use intra mode
block->mode = TEV_MODE_INTRA;
block->mv_x = 0;
block->mv_y = 0;
enc->blocks_intra++;
}
}
// Calculate block complexity BEFORE DCT transform for adaptive rate control
// Use enhanced complexity calculation that includes chroma information
float block_complexity = calculate_block_complexity_enhanced(enc->y_workspace, enc->co_workspace, enc->cg_workspace);
add_complexity_value(enc, block_complexity);
block->rate_control_factor = (enc->disable_rcf) ? 1.f : complexity_to_rate_factor(block_complexity);
// Apply fast DCT transform
dct_16x16_fast(enc->y_workspace, enc->dct_workspace);
// quantise Y coefficients (luma) using per-block rate control
const uint32_t *y_quant = enc->ictcp_mode ? QUANT_TABLE_Y : QUANT_TABLE_Y;
const float qmult_y = jpeg_quality_to_mult(enc->qualityY * block->rate_control_factor);
for (int i = 0; i < BLOCK_SIZE_SQR; i++) {
// Apply rate control factor to quantisation table (like decoder does)
float effective_quant = y_quant[i] * qmult_y;
block->y_coeffs[i] = quantise_coeff(enc->dct_workspace[i], FCLAMP(effective_quant, 1.f, 255.f), i == 0, 0);
}
// Apply fast DCT transform to chroma
dct_8x8_fast(enc->co_workspace, enc->dct_workspace);
// quantise Co coefficients (chroma - orange-blue) using per-block rate control
const uint32_t *co_quant = enc->ictcp_mode ? QUANT_TABLE_C : QUANT_TABLE_C;
const float qmult_co = jpeg_quality_to_mult(enc->qualityCo * block->rate_control_factor);
for (int i = 0; i < HALF_BLOCK_SIZE_SQR; i++) {
// Apply rate control factor to quantisation table (like decoder does)
float effective_quant = co_quant[i] * qmult_co;
block->co_coeffs[i] = quantise_coeff(enc->dct_workspace[i], FCLAMP(effective_quant, 1.f, 255.f), i == 0, 1);
}
// Apply fast DCT transform to Cg
dct_8x8_fast(enc->cg_workspace, enc->dct_workspace);
// quantise Cg coefficients (chroma - green-magenta, qmult_cg is more aggressive like NTSC Q) using per-block rate control
// In ICtCp mode, Cg becomes Cp (chroma-red) which needs special quantisation table
const uint32_t *cg_quant = enc->ictcp_mode ? QUANT_TABLE_C : QUANT_TABLE_C;
const float qmult_cg = jpeg_quality_to_mult(enc->qualityCg * block->rate_control_factor);
for (int i = 0; i < HALF_BLOCK_SIZE_SQR; i++) {
// Apply rate control factor to quantisation table (like decoder does)
float effective_quant = cg_quant[i] * qmult_cg;
block->cg_coeffs[i] = quantise_coeff(enc->dct_workspace[i], FCLAMP(effective_quant, 1.f, 255.f), i == 0, 1);
}
// Set CBP (simplified - always encode all channels)
block->cbp = 0x07; // Y, Co, Cg all present
}
// Convert SubRip time format (HH:MM:SS,mmm) to frame number
static int srt_time_to_frame(const char *time_str, int fps) {
int hours, minutes, seconds, milliseconds;
if (sscanf(time_str, "%d:%d:%d,%d", &hours, &minutes, &seconds, &milliseconds) != 4) {
return -1;
}
double total_seconds = hours * 3600.0 + minutes * 60.0 + seconds + milliseconds / 1000.0;
return (int)(total_seconds * fps + 0.5); // Round to nearest frame
}
// Convert SAMI milliseconds to frame number
static int sami_ms_to_frame(int milliseconds, int fps) {
double seconds = milliseconds / 1000.0;
return (int)(seconds * fps + 0.5); // Round to nearest frame
}
// Parse SubRip subtitle file
static subtitle_entry_t* parse_srt_file(const char *filename, int fps) {
FILE *file = fopen(filename, "r");
if (!file) {
fprintf(stderr, "Failed to open subtitle file: %s\n", filename);
return NULL;
}
subtitle_entry_t *head = NULL;
subtitle_entry_t *tail = NULL;
char line[1024];
int state = 0; // 0=index, 1=time, 2=text, 3=blank
subtitle_entry_t *current_entry = NULL;
char *text_buffer = NULL;
size_t text_buffer_size = 0;
while (fgets(line, sizeof(line), file)) {
// Remove trailing newline
size_t len = strlen(line);
if (len > 0 && line[len-1] == '\n') {
line[len-1] = '\0';
len--;
}
if (len > 0 && line[len-1] == '\r') {
line[len-1] = '\0';
len--;
}
if (state == 0) { // Expecting subtitle index
if (strlen(line) == 0) continue; // Skip empty lines
// Create new subtitle entry
current_entry = calloc(1, sizeof(subtitle_entry_t));
if (!current_entry) break;
state = 1;
} else if (state == 1) { // Expecting time range
char start_time[32], end_time[32];
if (sscanf(line, "%31s --> %31s", start_time, end_time) == 2) {
current_entry->start_frame = srt_time_to_frame(start_time, fps);
current_entry->end_frame = srt_time_to_frame(end_time, fps);
if (current_entry->start_frame < 0 || current_entry->end_frame < 0) {
free(current_entry);
current_entry = NULL;
state = 3; // Skip to next blank line
continue;
}
// Initialise text buffer
text_buffer_size = 256;
text_buffer = malloc(text_buffer_size);
if (!text_buffer) {
free(current_entry);
current_entry = NULL;
fprintf(stderr, "Memory allocation failed while parsing subtitles\n");
break;
}
text_buffer[0] = '\0';
state = 2;
} else {
free(current_entry);
current_entry = NULL;
state = 3; // Skip malformed entry
}
} else if (state == 2) { // Collecting subtitle text
if (strlen(line) == 0) {
// End of subtitle text
current_entry->text = strdup(text_buffer);
free(text_buffer);
text_buffer = NULL;
// Add to list
if (!head) {
head = current_entry;
tail = current_entry;
} else {
tail->next = current_entry;
tail = current_entry;
}
current_entry = NULL;
state = 0;
} else {
// Append text line
size_t current_len = strlen(text_buffer);
size_t line_len = strlen(line);
size_t needed = current_len + line_len + 2; // +2 for newline and null
if (needed > text_buffer_size) {
text_buffer_size = needed + 256;
char *new_buffer = realloc(text_buffer, text_buffer_size);
if (!new_buffer) {
free(text_buffer);
free(current_entry);
current_entry = NULL;
fprintf(stderr, "Memory allocation failed while parsing subtitles\n");
break;
}
text_buffer = new_buffer;
}
if (current_len > 0) {
strcat(text_buffer, "\n");
}
strcat(text_buffer, line);
}
} else if (state == 3) { // Skip to next blank line
if (strlen(line) == 0) {
state = 0;
}
}
}
// Handle final subtitle if file doesn't end with blank line
if (current_entry && text_buffer) {
current_entry->text = strdup(text_buffer);
free(text_buffer);
if (!head) {
head = current_entry;
} else {
tail->next = current_entry;
}
}
//fclose(file); // why uncommenting it errors out with "Fatal error: glibc detected an invalid stdio handle"?
return head;
}
// Strip HTML tags from text but preserve <b> and <i> formatting tags
static char* strip_html_tags(const char *html) {
if (!html) return NULL;
size_t len = strlen(html);
char *result = malloc(len + 1);
if (!result) return NULL;
int in_tag = 0;
int out_pos = 0;
int i = 0;
while (i < len) {
if (html[i] == '<') {
// Check if this is a formatting tag we want to preserve
int preserve_tag = 0;
// Check for <b>, </b>, <i>, </i> tags
if (i + 1 < len) {
if ((i + 2 < len && strncasecmp(&html[i], "<b>", 3) == 0) ||
(i + 3 < len && strncasecmp(&html[i], "</b>", 4) == 0) ||
(i + 2 < len && strncasecmp(&html[i], "<i>", 3) == 0) ||
(i + 3 < len && strncasecmp(&html[i], "</i>", 4) == 0)) {
preserve_tag = 1;
}
}
if (preserve_tag) {
// Copy the entire tag
while (i < len && html[i] != '>') {
result[out_pos++] = html[i++];
}
if (i < len) {
result[out_pos++] = html[i++]; // Copy the '>'
}
} else {
// Skip non-formatting tags
in_tag = 1;
i++;
}
} else if (html[i] == '>') {
in_tag = 0;
i++;
} else if (!in_tag) {
result[out_pos++] = html[i++];
} else {
i++;
}
}
result[out_pos] = '\0';
return result;
}
// Parse SAMI subtitle file
static subtitle_entry_t* parse_smi_file(const char *filename, int fps) {
FILE *file = fopen(filename, "r");
if (!file) {
fprintf(stderr, "Failed to open subtitle file: %s\n", filename);
return NULL;
}
subtitle_entry_t *head = NULL;
subtitle_entry_t *tail = NULL;
char line[2048];
char *content = NULL;
size_t content_size = 0;
size_t content_pos = 0;
// Read entire file into memory for easier parsing
while (fgets(line, sizeof(line), file)) {
size_t line_len = strlen(line);
// Expand content buffer if needed
if (content_pos + line_len + 1 > content_size) {
content_size = content_size ? content_size * 2 : 8192;
char *new_content = realloc(content, content_size);
if (!new_content) {
free(content);
fclose(file);
fprintf(stderr, "Memory allocation failed while parsing SAMI file\n");
return NULL;
}
content = new_content;
}
strcpy(content + content_pos, line);
content_pos += line_len;
}
fclose(file);
if (!content) return NULL;
// Convert to lowercase for case-insensitive parsing
char *content_lower = malloc(strlen(content) + 1);
if (!content_lower) {
free(content);
return NULL;
}
for (int i = 0; content[i]; i++) {
content_lower[i] = tolower(content[i]);
}
content_lower[strlen(content)] = '\0';
// Find BODY section
char *body_start = strstr(content_lower, "<body");
if (!body_start) {
fprintf(stderr, "No BODY section found in SAMI file\n");
free(content);
free(content_lower);
return NULL;
}
// Skip to actual body content
body_start = strchr(body_start, '>');
if (!body_start) {
free(content);
free(content_lower);
return NULL;
}
body_start++;
// Calculate offset in original content
size_t body_offset = body_start - content_lower;
char *body_content = content + body_offset;
// Parse SYNC tags
char *pos = content_lower + body_offset;
char *original_pos = body_content;
while ((pos = strstr(pos, "<sync")) != NULL) {
// Find start time
char *start_attr = strstr(pos, "start");
if (!start_attr || start_attr > strstr(pos, ">")) {
pos++;
continue;
}
// Parse start time
start_attr = strchr(start_attr, '=');
if (!start_attr) {
pos++;
continue;
}
start_attr++;
// Skip whitespace and quotes
while (*start_attr && (*start_attr == ' ' || *start_attr == '"' || *start_attr == '\'')) {
start_attr++;
}
int start_ms = atoi(start_attr);
if (start_ms < 0) {
pos++;
continue;
}
// Find end of sync tag
char *sync_end = strchr(pos, '>');
if (!sync_end) {
pos++;
continue;
}
sync_end++;
// Find next sync tag or end of body
char *next_sync = strstr(sync_end, "<sync");
char *body_end = strstr(sync_end, "</body>");
char *text_end = next_sync;
if (body_end && (!next_sync || body_end < next_sync)) {
text_end = body_end;
}
if (!text_end) {
// Use end of content
text_end = content_lower + strlen(content_lower);
}
// Extract subtitle text
size_t text_len = text_end - sync_end;
if (text_len > 0) {
// Get text from original content (not lowercase version)
size_t sync_offset = sync_end - content_lower;
char *subtitle_text = malloc(text_len + 1);
if (!subtitle_text) break;
strncpy(subtitle_text, content + sync_offset, text_len);
subtitle_text[text_len] = '\0';
// Strip HTML tags and clean up text
char *clean_text = strip_html_tags(subtitle_text);
free(subtitle_text);
if (clean_text && strlen(clean_text) > 0) {
// Remove leading/trailing whitespace
char *start = clean_text;
while (*start && (*start == ' ' || *start == '\t' || *start == '\n' || *start == '\r')) {
start++;
}
char *end = start + strlen(start) - 1;
while (end > start && (*end == ' ' || *end == '\t' || *end == '\n' || *end == '\r')) {
*end = '\0';
end--;
}
if (strlen(start) > 0) {
// Create subtitle entry
subtitle_entry_t *entry = calloc(1, sizeof(subtitle_entry_t));
if (entry) {
entry->start_frame = sami_ms_to_frame(start_ms, fps);
entry->text = strdup(start);
// Set end frame to next subtitle start or a default duration
if (next_sync) {
// Parse next sync start time
char *next_start = strstr(next_sync, "start");
if (next_start) {
next_start = strchr(next_start, '=');
if (next_start) {
next_start++;
while (*next_start && (*next_start == ' ' || *next_start == '"' || *next_start == '\'')) {
next_start++;
}
int next_ms = atoi(next_start);
if (next_ms > start_ms) {
entry->end_frame = sami_ms_to_frame(next_ms, fps);
} else {
entry->end_frame = entry->start_frame + fps * 3; // 3 second default
}
}
}
} else {
entry->end_frame = entry->start_frame + fps * 3; // 3 second default
}
// Add to list
if (!head) {
head = entry;
tail = entry;
} else {
tail->next = entry;
tail = entry;
}
}
}
}
free(clean_text);
}
pos = sync_end;
}
free(content);
free(content_lower);
return head;
}
// Detect subtitle file format based on extension and content
static int detect_subtitle_format(const char *filename) {
// Check file extension first
const char *ext = strrchr(filename, '.');
if (ext) {
ext++; // Skip the dot
if (strcasecmp(ext, "smi") == 0 || strcasecmp(ext, "sami") == 0) {
return 1; // SAMI format
}
if (strcasecmp(ext, "srt") == 0) {
return 2; // SubRip format
}
}
// If extension is unclear, try to detect from content
FILE *file = fopen(filename, "r");
if (!file) return 0; // Default to SRT
char line[1024];
int has_sami_tags = 0;
int has_srt_format = 0;
int lines_checked = 0;
while (fgets(line, sizeof(line), file) && lines_checked < 20) {
// Convert to lowercase for checking
char *lower_line = malloc(strlen(line) + 1);
if (lower_line) {
for (int i = 0; line[i]; i++) {
lower_line[i] = tolower(line[i]);
}
lower_line[strlen(line)] = '\0';
// Check for SAMI indicators
if (strstr(lower_line, "<sami>") || strstr(lower_line, "<sync") ||
strstr(lower_line, "<body>") || strstr(lower_line, "start=")) {
has_sami_tags = 1;
free(lower_line);
break;
}
// Check for SRT indicators (time format)
if (strstr(lower_line, "-->")) {
has_srt_format = 1;
}
free(lower_line);
}
lines_checked++;
}
fclose(file);
// Return format based on detection
if (has_sami_tags) return 1; // SAMI
if (has_srt_format) return 2; // SRT
return 0; // Unknown
}
// Parse subtitle file (auto-detect format)
static subtitle_entry_t* parse_subtitle_file(const char *filename, int fps) {
int format = detect_subtitle_format(filename);
if (format == 1) return parse_smi_file(filename, fps);
else if (format == 2) return parse_srt_file(filename, fps);
else return NULL;
}
// Free subtitle list
static void free_subtitle_list(subtitle_entry_t *list) {
while (list) {
subtitle_entry_t *next = list->next;
free(list->text);
free(list);
list = next;
}
}
// Write SSF-TC subtitle packet to output
static int write_subtitle_packet_tc(FILE *output, uint32_t index, uint8_t opcode, const char *text, uint64_t timecode_ns) {
// Calculate packet size: index (3 bytes) + timecode (8 bytes) + opcode (1 byte) + text + null terminator
size_t text_len = text ? strlen(text) : 0;
size_t packet_size = 3 + 8 + 1 + text_len + 1;
// Write packet type and size
uint8_t packet_type = TEV_PACKET_SUBTITLE_TC;
fwrite(&packet_type, 1, 1, output);
fwrite(&packet_size, 4, 1, output);
// Write subtitle index (24-bit, little-endian)
uint8_t index_bytes[3];
index_bytes[0] = index & 0xFF;
index_bytes[1] = (index >> 8) & 0xFF;
index_bytes[2] = (index >> 16) & 0xFF;
fwrite(index_bytes, 1, 3, output);
// Write timecode (64-bit, little-endian)
uint8_t timecode_bytes[8];
for (int i = 0; i < 8; i++) {
timecode_bytes[i] = (timecode_ns >> (i * 8)) & 0xFF;
}
fwrite(timecode_bytes, 1, 8, output);
// Write opcode
fwrite(&opcode, 1, 1, output);
// Write text if present
if (text && text_len > 0) {
fwrite(text, 1, text_len, output);
}
// Write null terminator
uint8_t null_term = 0x00;
fwrite(&null_term, 1, 1, output);
return packet_size + 5; // packet_size + packet_type + size field
}
// Write all subtitles upfront in SSF-TC format (called before first frame)
static int write_all_subtitles_tc(tev_encoder_t *enc, FILE *output) {
if (!enc->has_subtitles) return 0;
int bytes_written = 0;
int subtitle_count = 0;
// Convert frame timing to nanoseconds
// Frame time = 1e9 / fps nanoseconds
uint64_t frame_time_ns = (uint64_t)(1000000000.0 / enc->output_fps);
// Iterate through all subtitles and write them with timecodes
subtitle_entry_t *sub = enc->subtitle_list;
while (sub) {
// Calculate timecodes for show and hide events
uint64_t show_timecode = (uint64_t)sub->start_frame * frame_time_ns;
uint64_t hide_timecode = (uint64_t)sub->end_frame * frame_time_ns;
// Write show subtitle event
bytes_written += write_subtitle_packet_tc(output, 0, 0x01, sub->text, show_timecode);
// Write hide subtitle event
bytes_written += write_subtitle_packet_tc(output, 0, 0x02, NULL, hide_timecode);
subtitle_count++;
if (enc->verbose) {
printf("SSF-TC: Subtitle %d: show at %.3fs, hide at %.3fs: %.50s%s\n",
subtitle_count,
show_timecode / 1000000000.0,
hide_timecode / 1000000000.0,
sub->text, strlen(sub->text) > 50 ? "..." : "");
}
sub = sub->next;
}
if (enc->verbose && subtitle_count > 0) {
printf("Wrote %d SSF-TC subtitle events (%d bytes)\n", subtitle_count * 2, bytes_written);
}
return bytes_written;
}
// Initialise encoder
static tev_encoder_t* init_encoder(void) {
tev_encoder_t *enc = calloc(1, sizeof(tev_encoder_t));
if (!enc) return NULL;
// set defaults
enc->qualityIndex = 2; // Default quality
enc->qualityY = QUALITY_Y[enc->qualityIndex];
enc->qualityCo = QUALITY_CO[enc->qualityIndex];
enc->qualityCg = enc->qualityCo / 2;
enc->mp2_packet_size = 0; // Will be detected from MP2 header
enc->mp2_rate_index = 0;
enc->audio_bitrate = 0; // 0 = use quality table
enc->audio_frames_in_buffer = 0;
enc->target_audio_buffer_size = 4;
enc->width = DEFAULT_WIDTH;
enc->height = DEFAULT_HEIGHT;
enc->fps = 0; // Will be detected from input
enc->output_fps = 0; // No frame rate conversion by default
enc->is_ntsc_framerate = 0; // Will be detected from input
enc->verbose = 0;
enc->disable_rcf = 1;
enc->subtitle_file = NULL;
enc->has_subtitles = 0;
enc->subtitle_list = NULL;
enc->current_subtitle = NULL;
// Rate control defaults
enc->target_bitrate_kbps = 0; // 0 = quality mode
enc->bitrate_mode = 0; // Quality mode by default
// No global rate control factor needed - per-block complexity-based control only
enc->frame_bits_accumulator = 0;
enc->target_bits_per_frame = 0;
enc->complexity_history_index = 0;
enc->average_complexity = 0.0f;
memset(enc->complexity_history, 0, sizeof(enc->complexity_history));
init_dct_tables();
return enc;
}
// Allocate encoder buffers
static int alloc_encoder_buffers(tev_encoder_t *enc) {
// In interlaced mode, FFmpeg separatefields outputs field frames at half height
// In progressive mode, we work with full height frames
int encoding_pixels = enc->width * enc->height;
int blocks_x = (enc->width + 15) / 16;
int blocks_y = (enc->height + 15) / 16;
int total_blocks = blocks_x * blocks_y;
// Allocate buffers for encoding (FFmpeg provides frames at the correct resolution)
enc->current_rgb = malloc(encoding_pixels * 3); // Current frame buffer from FFmpeg
enc->previous_rgb = malloc(encoding_pixels * 3); // Previous frame buffer for motion estimation
enc->reference_rgb = malloc(encoding_pixels * 3); // Reference frame buffer
enc->previous_even_field = malloc(encoding_pixels * 3); // Previous even field for interlaced scene change
enc->y_workspace = malloc(16 * 16 * sizeof(float));
enc->co_workspace = malloc(8 * 8 * sizeof(float));
enc->cg_workspace = malloc(8 * 8 * sizeof(float));
enc->dct_workspace = malloc(16 * 16 * sizeof(float));
// Allocate block data
enc->block_data = malloc(total_blocks * sizeof(tev_block_t));
// Allocate compression buffer
size_t compressed_buffer_size = total_blocks * sizeof(tev_block_t) * 2;
enc->compressed_buffer = malloc(compressed_buffer_size);
enc->mp2_buffer = malloc(MP2_DEFAULT_PACKET_SIZE);
if (!enc->current_rgb || !enc->previous_rgb || !enc->reference_rgb ||
!enc->previous_even_field ||
!enc->y_workspace || !enc->co_workspace || !enc->cg_workspace ||
!enc->dct_workspace || !enc->block_data ||
!enc->compressed_buffer || !enc->mp2_buffer) {
return -1;
}
// Initialise Zstd compression context
enc->zstd_context = ZSTD_createCCtx();
if (!enc->zstd_context) {
fprintf(stderr, "Failed to initialise Zstd compression\n");
return 0;
}
// Set reasonable compression level and memory limits
ZSTD_CCtx_setParameter(enc->zstd_context, ZSTD_c_compressionLevel, ZSTD_COMPRESSON_LEVEL);
ZSTD_CCtx_setParameter(enc->zstd_context, ZSTD_c_windowLog, 24); // 16MB window (should be plenty to hold an entire frame; interframe compression is unavailable)
ZSTD_CCtx_setParameter(enc->zstd_context, ZSTD_c_hashLog, 16);
// Initialise previous frame to black
memset(enc->previous_rgb, 0, encoding_pixels * 3);
memset(enc->previous_even_field, 0, encoding_pixels * 3);
return 1;
}
// Free encoder resources
static void free_encoder(tev_encoder_t *enc) {
if (!enc) return;
if (enc->zstd_context) {
ZSTD_freeCCtx(enc->zstd_context);
enc->zstd_context = NULL;
}
if (enc->current_rgb) { free(enc->current_rgb); enc->current_rgb = NULL; }
if (enc->previous_rgb) { free(enc->previous_rgb); enc->previous_rgb = NULL; }
if (enc->reference_rgb) { free(enc->reference_rgb); enc->reference_rgb = NULL; }
if (enc->previous_even_field) { free(enc->previous_even_field); enc->previous_even_field = NULL; }
if (enc->y_workspace) { free(enc->y_workspace); enc->y_workspace = NULL; }
if (enc->co_workspace) { free(enc->co_workspace); enc->co_workspace = NULL; }
if (enc->cg_workspace) { free(enc->cg_workspace); enc->cg_workspace = NULL; }
if (enc->dct_workspace) { free(enc->dct_workspace); enc->dct_workspace = NULL; }
if (enc->block_data) { free(enc->block_data); enc->block_data = NULL; }
if (enc->compressed_buffer) { free(enc->compressed_buffer); enc->compressed_buffer = NULL; }
if (enc->mp2_buffer) { free(enc->mp2_buffer); enc->mp2_buffer = NULL; }
if (enc->complexity_values) { free(enc->complexity_values); enc->complexity_values = NULL; }
free(enc);
}
// Write TEV header
static int write_tev_header(FILE *output, tev_encoder_t *enc) {
// Magic + version
fwrite(TEV_MAGIC, 1, 8, output);
uint8_t version = enc->ictcp_mode ? 3 : 2; // Version 3 for ICtCp, 2 for YCoCg-R
fwrite(&version, 1, 1, output);
// Video parameters
uint16_t width = enc->width;
uint16_t height = enc->progressive_mode ? enc->height : enc->height * 2;
uint8_t fps = enc->output_fps;
uint32_t total_frames = enc->total_frames;
uint8_t qualityY = enc->qualityY;
uint8_t qualityCo = enc->qualityCo;
uint8_t qualityCg = enc->qualityCg;
uint8_t flags = (enc->has_audio) | (enc->has_subtitles << 1);
uint8_t video_flags = (enc->progressive_mode ? 0 : 1) | (enc->is_ntsc_framerate ? 2 : 0); // bit 0 = is_interlaced, bit 1 = is_ntsc_framerate
uint8_t reserved = 0;
fwrite(&width, 2, 1, output);
fwrite(&height, 2, 1, output);
fwrite(&fps, 1, 1, output);
fwrite(&total_frames, 4, 1, output);
fwrite(&qualityY, 1, 1, output);
fwrite(&qualityCo, 1, 1, output);
fwrite(&qualityCg, 1, 1, output);
fwrite(&flags, 1, 1, output);
fwrite(&video_flags, 1, 1, output);
fwrite(&reserved, 1, 1, output);
return 0;
}
// Detect scene changes by analysing frame differences
static int detect_scene_change(tev_encoder_t *enc, int field_parity) {
if (!enc->current_rgb) {
return 0; // No current frame to compare
}
// In interlaced mode, use previous even field for comparison
uint8_t *comparison_buffer = enc->previous_rgb;
if (!enc->progressive_mode && field_parity == 0) {
// Interlaced even field: compare to previous even field
if (!enc->previous_even_field) {
return 0; // No previous even field to compare
}
comparison_buffer = enc->previous_even_field;
} else {
// Progressive mode: use regular previous_rgb
if (!enc->previous_rgb) {
return 0; // No previous frame to compare
}
comparison_buffer = enc->previous_rgb;
}
long long total_diff = 0;
int changed_pixels = 0;
// Sample every 4th pixel for performance (still gives good detection)
for (int y = 0; y < enc->height; y += 2) {
for (int x = 0; x < enc->width; x += 2) {
int offset = (y * enc->width + x) * 3;
// Calculate colour difference
int r_diff = abs(enc->current_rgb[offset] - comparison_buffer[offset]);
int g_diff = abs(enc->current_rgb[offset + 1] - comparison_buffer[offset + 1]);
int b_diff = abs(enc->current_rgb[offset + 2] - comparison_buffer[offset + 2]);
int pixel_diff = r_diff + g_diff + b_diff;
total_diff += pixel_diff;
// Count significantly changed pixels (threshold of 30 per channel average)
if (pixel_diff > 90) {
changed_pixels++;
}
}
}
// Calculate metrics for scene change detection
int sampled_pixels = (enc->height / 2) * (enc->width / 2);
double avg_diff = (double)total_diff / sampled_pixels;
double changed_ratio = (double)changed_pixels / sampled_pixels;
if (enc->verbose) {
printf("Scene change detection: avg_diff=%.2f\tchanged_ratio=%.4f\n", avg_diff, changed_ratio);
}
// Scene change thresholds - adjust for interlaced mode
// Interlaced fields have more natural differences due to temporal field separation
double threshold = 0.30;
return changed_ratio > threshold;
}
// Encode and write a frame
static int encode_frame(tev_encoder_t *enc, FILE *output, int frame_num, int field_parity) {
// In interlaced mode, only do scene change detection for even fields (field_parity = 0)
// to avoid false scene changes between fields of the same frame
int is_scene_change = 0;
if (enc->progressive_mode || field_parity == 0) {
is_scene_change = detect_scene_change(enc, field_parity);
}
int is_time_keyframe = (frame_num % KEYFRAME_INTERVAL) == 0;
int is_keyframe = is_time_keyframe || is_scene_change;
// Verbose output for keyframe decisions
if (enc->verbose && is_keyframe) {
if (is_scene_change && !is_time_keyframe) {
printf("Frame %d: Scene change detected, inserting keyframe\n", frame_num);
} else if (is_time_keyframe) {
printf("Frame %d: Time-based keyframe (interval: %d)\n", frame_num, KEYFRAME_INTERVAL);
}
}
int blocks_x = (enc->width + 15) / 16;
int blocks_y = (enc->height + 15) / 16;
// Track frame complexity for rate control
float frame_complexity = 0.0f;
size_t frame_start_bits = enc->total_output_bytes * 8;
// Encode all blocks
for (int by = 0; by < blocks_y; by++) {
for (int bx = 0; bx < blocks_x; bx++) {
encode_block(enc, bx, by, is_keyframe);
// Calculate complexity for rate control (if enabled)
if (enc->bitrate_mode > 0) {
tev_block_t *block = &enc->block_data[by * blocks_x + bx];
if (block->mode == TEV_MODE_INTRA || block->mode == TEV_MODE_INTER) {
// Sum absolute values of quantised coefficients as complexity metric
for (int i = 1; i < BLOCK_SIZE_SQR; i++) frame_complexity += abs(block->y_coeffs[i]);
for (int i = 1; i < HALF_BLOCK_SIZE_SQR; i++) frame_complexity += abs(block->co_coeffs[i]);
for (int i = 1; i < HALF_BLOCK_SIZE_SQR; i++) frame_complexity += abs(block->cg_coeffs[i]);
}
}
}
}
// Compress block data using Zstd (compatible with TSVM decoder)
size_t compressed_size;
// Regular mode: use regular block data
size_t block_data_size = blocks_x * blocks_y * sizeof(tev_block_t);
compressed_size = ZSTD_compressCCtx(enc->zstd_context,
enc->compressed_buffer, block_data_size * 2,
enc->block_data, block_data_size,
ZSTD_COMPRESSON_LEVEL);
if (ZSTD_isError(compressed_size)) {
fprintf(stderr, "Zstd compression failed: %s\n", ZSTD_getErrorName(compressed_size));
return 0;
}
// Write frame packet header (rate control factor now per-block)
uint8_t packet_type = is_keyframe ? TEV_PACKET_IFRAME : TEV_PACKET_PFRAME;
uint32_t payload_size = compressed_size; // Rate control factor now per-block, not per-packet
fwrite(&packet_type, 1, 1, output);
fwrite(&payload_size, 4, 1, output);
fwrite(enc->compressed_buffer, 1, compressed_size, output);
if (enc->verbose) {
printf("perBlockComplexityBasedRateControl=enabled\n");
}
enc->total_output_bytes += 5 + compressed_size; // packet + size + data (rate_factor now per-block)
// No global rate control needed - per-block complexity-based control only
// Swap frame buffers for next frame
if (!enc->progressive_mode && field_parity == 0) {
// Interlaced even field: save to previous_even_field for scene change detection
size_t field_size = enc->width * enc->height * 3;
memcpy(enc->previous_even_field, enc->current_rgb, field_size);
}
// Normal buffer swap for motion estimation
uint8_t *temp_rgb = enc->previous_rgb;
enc->previous_rgb = enc->current_rgb;
enc->current_rgb = temp_rgb;
return 1;
}
// Parse resolution string like "1024x768"
static int parse_resolution(const char *res_str, int *width, int *height) {
if (!res_str) return 0;
if (strcmp(res_str, "cif") == 0 || strcmp(res_str, "CIF") == 0) {
*width = 352;
*height = 288;
return 1;
}
if (strcmp(res_str, "qcif") == 0 || strcmp(res_str, "QCIF") == 0) {
*width = 176;
*height = 144;
return 1;
}
if (strcmp(res_str, "half") == 0 || strcmp(res_str, "HALF") == 0) {
*width = DEFAULT_WIDTH >> 1;
*height = DEFAULT_HEIGHT >> 1;
return 1;
}
if (strcmp(res_str, "default") == 0 || strcmp(res_str, "DEFAULT") == 0) {
*width = DEFAULT_WIDTH;
*height = DEFAULT_HEIGHT;
return 1;
}
return sscanf(res_str, "%dx%d", width, height) == 2;
}
// Execute command and capture output
static char *execute_command(const char *command) {
FILE *pipe = popen(command, "r");
if (!pipe) return NULL;
char *result = malloc(4096);
if (!result) {
pclose(pipe);
return NULL;
}
size_t len = fread(result, 1, 4095, pipe);
result[len] = '\0';
pclose(pipe);
return result;
}
// Get video metadata using ffprobe
static int get_video_metadata(tev_encoder_t *config) {
char command[1024];
char *output;
// Get all metadata without frame count (much faster)
snprintf(command, sizeof(command),
"ffprobe -v quiet "
"-show_entries stream=r_frame_rate:format=duration "
"-select_streams v:0 -of csv=p=0 \"%s\" 2>/dev/null; "
"ffprobe -v quiet -select_streams a:0 -show_entries stream=index -of csv=p=0 \"%s\" 2>/dev/null",
config->input_file, config->input_file);
output = execute_command(command);
if (!output) {
fprintf(stderr, "Failed to get video metadata (ffprobe failed)\n");
return 0;
}
// Parse the combined output
char *line = strtok(output, "\n");
int line_num = 0;
int input_is_ntsc_framerate = 0;
while (line && line_num < 2) {
switch (line_num) {
case 0: // Line format: "framerate" (e.g., "30000/1001"), (e.g., "30/1")
{
// Parse frame rate
int num, den;
if (sscanf(line, "%d/%d", &num, &den) == 2) {
config->fps = (den > 0) ? (int)round((float)num/(float)den) : 30;
config->is_ntsc_framerate = (den == 1001 && config->output_fps == 0) ? 1 : 0; // set NTSC framerate mode only when the user did not supply fps option
input_is_ntsc_framerate = (den == 1001) ? 1 : 0;
} else {
config->fps = (int)round(atof(line));
config->is_ntsc_framerate = 0;
}
// Frame count will be determined during encoding
config->total_frames = 0;
}
break;
case 1: // duration in seconds
config->duration = atof(line);
break;
}
line = strtok(NULL, "\n");
line_num++;
}
// Check for audio stream (will be on line 3 if present)
config->has_audio = (line && strlen(line) > 0 && atoi(line) >= 0);
free(output);
// Store input framerate for later calculations
float inputFramerate;
if (input_is_ntsc_framerate) {
inputFramerate = config->fps * 1000.f / 1001.f;
} else {
inputFramerate = config->fps * 1.f;
}
// if output FPS is unspecified, use the input rate
if (config->output_fps == 0) {
config->output_fps = config->fps;
}
// Frame count will be determined during encoding
config->total_frames = 0;
fprintf(stderr, "Video metadata:\n");
fprintf(stderr, " Frames: (will be determined during encoding)\n");
fprintf(stderr, " FPS: %.2f\n", inputFramerate);
fprintf(stderr, " Duration: %.2fs\n", config->duration);
fprintf(stderr, " Audio: %s\n", config->has_audio ? "Yes" : "No");
fprintf(stderr, " Resolution: %dx%d (%s)\n", config->width, config->height,
config->progressive_mode ? "progressive" : "interlaced");
return (config->fps > 0);
}
// Start FFmpeg process for video conversion with frame rate support
static int start_video_conversion(tev_encoder_t *enc) {
char command[2048];
// Build FFmpeg command with potential frame rate conversion
if (enc->progressive_mode) {
if (enc->output_fps > 0 && enc->output_fps != enc->fps) {
// Frame rate conversion requested
snprintf(command, sizeof(command),
"ffmpeg -v error -i \"%s\" -f rawvideo -pix_fmt rgb24 "
"-vf \"fps=%d,scale=%d:%d:force_original_aspect_ratio=increase,crop=%d:%d\" "
"-y - 2>&1",
enc->input_file, enc->output_fps, enc->width, enc->height, enc->width, enc->height);
} else {
// No frame rate conversion
snprintf(command, sizeof(command),
"ffmpeg -v error -i \"%s\" -f rawvideo -pix_fmt rgb24 "
"-vf \"scale=%d:%d:force_original_aspect_ratio=increase,crop=%d:%d\" "
"-y -",
enc->input_file, enc->width, enc->height, enc->width, enc->height);
}
// let FFmpeg handle the interlacing
} else {
if (enc->output_fps > 0 && enc->output_fps != enc->fps) {
// Frame rate conversion requested
// filtergraph path:
// 1. FPS conversion
// 2. scale and crop to requested size
// 3. tinterlace weave-overwrites even and odd fields together to produce intermediate video at half framerate, full height (we're losing half the information here -- and that's on purpose)
// 4. separatefields separates weave-overwritten frame as two consecutive frames, at half height. Since the frame rate is halved in Step 3. and being doubled here, the final framerate is identical to given framerate
snprintf(command, sizeof(command),
"ffmpeg -v error -i \"%s\" -f rawvideo -pix_fmt rgb24 "
"-vf \"fps=%d,scale=%d:%d:force_original_aspect_ratio=increase,crop=%d:%d,tinterlace=interleave_top:cvlpf,separatefields\" "
"-y - 2>&1",
enc->input_file, enc->output_fps, enc->width, enc->height * 2, enc->width, enc->height * 2);
} else {
// No frame rate conversion
// filtergraph path:
// 1. scale and crop to requested size
// 2. tinterlace weave-overwrites even and odd fields together to produce intermediate video at half framerate, full height (we're losing half the information here -- and that's on purpose)
// 3. separatefields separates weave-overwritten frame as two consecutive frames, at half height. Since the frame rate is halved in Step 2. and being doubled here, the final framerate is identical to the original framerate
snprintf(command, sizeof(command),
"ffmpeg -v error -i \"%s\" -f rawvideo -pix_fmt rgb24 "
"-vf \"scale=%d:%d:force_original_aspect_ratio=increase,crop=%d:%d,tinterlace=interleave_top:cvlpf,separatefields\" "
"-y -",
enc->input_file, enc->width, enc->height * 2, enc->width, enc->height * 2);
}
}
if (enc->verbose) {
printf("FFmpeg command: %s\n", command);
}
enc->ffmpeg_video_pipe = popen(command, "r");
if (!enc->ffmpeg_video_pipe) {
fprintf(stderr, "Failed to start FFmpeg process\n");
return 0;
}
return 1;
}
// Start audio conversion
static int start_audio_conversion(tev_encoder_t *enc) {
if (!enc->has_audio) return 1;
char command[2048];
int bitrate = (enc->audio_bitrate > 0) ? enc->audio_bitrate : MP2_RATE_TABLE[enc->qualityIndex];
snprintf(command, sizeof(command),
"ffmpeg -v quiet -i \"%s\" -acodec libtwolame -psymodel 4 -b:a %dk -ar %d -ac 2 -y \"%s\" 2>/dev/null",
enc->input_file, bitrate, MP2_SAMPLE_RATE, TEMP_AUDIO_FILE);
int result = system(command);
if (result == 0) {
enc->mp2_file = fopen(TEMP_AUDIO_FILE, "rb");
if (enc->mp2_file) {
fseek(enc->mp2_file, 0, SEEK_END);
enc->audio_remaining = ftell(enc->mp2_file);
fseek(enc->mp2_file, 0, SEEK_SET);
}
}
return (result == 0);
}
// Get MP2 packet size and rate index from header
static int get_mp2_packet_size(uint8_t *header) {
int bitrate_index = (header[2] >> 4) & 0x0F;
int bitrates[] = {0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384};
if (bitrate_index >= 15) return MP2_DEFAULT_PACKET_SIZE;
int bitrate = bitrates[bitrate_index];
int padding_bit = (header[2] >> 1) & 0x01;
if (bitrate <= 0) return MP2_DEFAULT_PACKET_SIZE;
int frame_size = (144 * bitrate * 1000) / MP2_SAMPLE_RATE + padding_bit;
return frame_size;
}
static int mp2_packet_size_to_rate_index(int packet_size, int is_mono) {
// Map packet sizes to rate indices for TEV format
const int mp2_frame_sizes[] = {144,216,252,288,360,432,504,576,720,864,1008,1152,1440,1728};
for (int i = 0; i < 14; i++) {
if (packet_size <= mp2_frame_sizes[i]) {
return i;
}
}
return 13; // Default to highest rate
}
// Process audio for current frame
static int process_audio(tev_encoder_t *enc, int frame_num, FILE *output) {
if (!enc->has_audio || !enc->mp2_file || enc->audio_remaining <= 0) {
return 1;
}
// Initialise packet size on first frame
if (enc->mp2_packet_size == 0) {
uint8_t header[4];
if (fread(header, 1, 4, enc->mp2_file) != 4) return 1;
fseek(enc->mp2_file, 0, SEEK_SET);
enc->mp2_packet_size = get_mp2_packet_size(header);
int is_mono = (header[3] >> 6) == 3;
enc->mp2_rate_index = mp2_packet_size_to_rate_index(enc->mp2_packet_size, is_mono);
enc->target_audio_buffer_size = 4; // 4 audio packets in buffer
}
// Calculate how much audio time each frame represents (in seconds)
double frame_audio_time = 1.0 / enc->output_fps;
// Calculate how much audio time each MP2 packet represents
// MP2 frame contains 1152 samples at 32kHz = 0.036 seconds
double packet_audio_time = 1152.0 / MP2_SAMPLE_RATE;
// Estimate how many packets we consume per video frame
double packets_per_frame = frame_audio_time / packet_audio_time;
// Audio buffering strategy: maintain target buffer level
int packets_to_insert = 0;
if (frame_num == 0) {
// Prime buffer to target level initially
packets_to_insert = enc->target_audio_buffer_size;
enc->audio_frames_in_buffer = 0; // count starts from 0
if (enc->verbose) {
printf("Frame %d: Priming audio buffer with %d packets\n", frame_num, packets_to_insert);
}
} else {
// Simulate buffer consumption (fractional consumption per frame)
double old_buffer = enc->audio_frames_in_buffer;
enc->audio_frames_in_buffer -= packets_per_frame;
// Calculate how many packets we need to maintain target buffer level
// Only insert when buffer drops below target, and only insert enough to restore target
double target_level = (double)enc->target_audio_buffer_size;
if (enc->audio_frames_in_buffer < target_level) {
double deficit = target_level - enc->audio_frames_in_buffer;
// Insert packets to cover the deficit, but at least maintain minimum flow
packets_to_insert = (int)ceil(deficit);
// Cap at reasonable maximum to prevent excessive insertion
if (packets_to_insert > enc->target_audio_buffer_size) {
packets_to_insert = enc->target_audio_buffer_size;
}
if (enc->verbose) {
printf("Frame %d: Buffer low (%.2f->%.2f), deficit %.2f, inserting %d packets\n",
frame_num, old_buffer, enc->audio_frames_in_buffer, deficit, packets_to_insert);
}
} else if (enc->verbose && old_buffer != enc->audio_frames_in_buffer) {
printf("Frame %d: Buffer sufficient (%.2f->%.2f), no packets\n",
frame_num, old_buffer, enc->audio_frames_in_buffer);
}
}
// Insert the calculated number of audio packets
for (int q = 0; q < packets_to_insert; q++) {
size_t bytes_to_read = enc->mp2_packet_size;
if (bytes_to_read > enc->audio_remaining) {
bytes_to_read = enc->audio_remaining;
}
size_t bytes_read = fread(enc->mp2_buffer, 1, bytes_to_read, enc->mp2_file);
if (bytes_read == 0) break;
// Write TEV MP2 audio packet
uint8_t audio_packet_type = TEV_PACKET_AUDIO_MP2;
uint32_t audio_len = (uint32_t)bytes_read;
fwrite(&audio_packet_type, 1, 1, output);
fwrite(&audio_len, 4, 1, output);
fwrite(enc->mp2_buffer, 1, bytes_read, output);
// Track audio bytes written
enc->total_output_bytes += 1 + 4 + bytes_read;
enc->audio_remaining -= bytes_read;
enc->audio_frames_in_buffer++;
if (frame_num == 0) {
enc->audio_frames_in_buffer = enc->target_audio_buffer_size / 2; // trick the buffer simulator so that it doesn't count the frame 0 priming
}
if (enc->verbose) {
printf("Audio packet %d: %zu bytes (buffer: %.2f packets)\n",
q, bytes_read, enc->audio_frames_in_buffer);
}
}
return 1;
}
// Show usage information
static void show_usage(const char *program_name) {
printf("TEV YCoCg-R/ICtCp 4:2:0 Video Encoder\n");
printf("Usage: %s [options] -i input.mp4 -o output.mv2\n\n", program_name);
printf("Options:\n");
printf(" -i, --input FILE Input video file\n");
printf(" -o, --output FILE Output video file (use '-' for stdout)\n");
printf(" -s, --size WxH Video size (default: %dx%d)\n", DEFAULT_WIDTH, DEFAULT_HEIGHT);
printf(" -f, --fps N Output frames per second (enables frame rate conversion)\n");
printf(" -q, --quality N Quality level 0-4 (default: 2, only decides audio rate in quantiser/lossless mode)\n");
printf(" -Q, --quantiser N Quantiser level 0-100 (100: lossless, 0: potato)\n");
// printf(" -b, --bitrate N Target bitrate in kbps (enables bitrate control mode; DON'T USE - NOT WORKING AS INTENDED)\n");
printf(" --arate N MP2 audio bitrate in kbps (overrides quality-based audio rate)\n");
printf(" Valid values: 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384\n");
printf(" -p, --progressive Use progressive scan (default: interlaced)\n");
printf(" -S, --subtitles FILE SubRip (.srt) or SAMI (.smi) subtitle file\n");
printf(" -v, --verbose Verbose output\n");
printf(" -t, --test Test mode: generate solid colour frames\n");
printf(" --ictcp Use ICtCp colour space instead of YCoCg-R (generates TEV version 3)\n");
printf(" --enable-rcf Enable per-block rate control (experimental)\n");
printf(" --enable-encode-stats Collect and report block complexity statistics\n");
printf(" --help Show this help\n\n");
// printf("Rate Control Modes:\n");
// printf(" Quality mode (default): Fixed quantisation based on -q parameter\n");
// printf(" Bitrate mode (-b N): Dynamic quantisation targeting N kbps average\n\n");
printf("Audio Rate by Quality:\n");
printf(" ");
for (int i = 0; i < sizeof(MP2_RATE_TABLE) / sizeof(int); i++) {
printf("%d: %d kbps\t", i, MP2_RATE_TABLE[i]);
}
printf("\nQuantiser Value by Quality:\n");
printf(" ");
for (int i = 0; i < sizeof(QUALITY_Y) / sizeof(int); i++) {
printf("%d: -Q %d \t", i, QUALITY_Y[i]);
}
printf("\nVideo Size Keywords:");
printf("\n -s cif: equal to 352x288");
printf("\n -s qcif: equal to 176x144");
printf("\n -s half: equal to %dx%d", DEFAULT_WIDTH >> 1, DEFAULT_HEIGHT >> 1);
printf("\n -s default: equal to %dx%d", DEFAULT_WIDTH, DEFAULT_HEIGHT);
printf("\n\n");
printf("Features:\n");
printf(" - YCoCg-R or ICtCp 4:2:0 chroma subsampling for 50%% compression improvement\n");
printf(" - 16x16 Y blocks with 8x8 chroma for optimal DCT efficiency\n");
printf(" - Frame rate conversion with FFmpeg temporal filtering\n");
printf(" - Adaptive quality control with complexity-based adjustment\n");
printf("Examples:\n");
printf(" %s -i input.mp4 -o output.mv2 # Use default setting (q=2)\n", program_name);
printf(" %s -i input.mkv -s cif -o output.mv2 # Encode at CIF (352x288) resolution\n", program_name);
printf(" %s -i input.mxf -f 15 -q 3 -p -o output.mv2 # Encode at 15 FPS progressive with higher quality\n", program_name);
printf(" %s -i input.webp -Q 50 -o output.mv2 # Encode at quantiser level 50\n", program_name);
printf(" %s -i input.flv -S input.srt -o output.mv2 # With SubRip subtitles\n", program_name);
printf(" %s -i input.ts -S input.smi -o output.mv2 # With SAMI subtitles\n", program_name);
// printf(" %s -i input.mp4 -b 800 -o output.mv2 # 800 kbps bitrate target\n", program_name);
// printf(" %s -i input.avi -f 15 -b 500 -o output.mv2 # 15fps @ 500 kbps\n", program_name);
// printf(" %s --test -b 1000 -o test.mv2 # Test with 1000 kbps target\n", program_name);
}
// Cleanup encoder resources
static void cleanup_encoder(tev_encoder_t *enc) {
if (!enc) return;
if (enc->ffmpeg_video_pipe) {
pclose(enc->ffmpeg_video_pipe);
enc->ffmpeg_video_pipe = NULL;
}
if (enc->mp2_file) {
fclose(enc->mp2_file);
enc->mp2_file = NULL;
unlink(TEMP_AUDIO_FILE); // Remove temporary audio file
}
if (enc->input_file) { free(enc->input_file); enc->input_file = NULL; }
if (enc->output_file) { free(enc->output_file); enc->output_file = NULL; }
if (enc->subtitle_file) { free(enc->subtitle_file); enc->subtitle_file = NULL; }
free_subtitle_list(enc->subtitle_list);
free_encoder(enc);
}
int sync_packet_count = 0;
// Main function
int main(int argc, char *argv[]) {
generate_random_filename(TEMP_AUDIO_FILE);
printf("Initialising encoder...\n");
tev_encoder_t *enc = init_encoder();
if (!enc) {
fprintf(stderr, "Failed to initialise encoder\n");
return 1;
}
int test_mode = 0;
static struct option long_options[] = {
{"input", required_argument, 0, 'i'},
{"output", required_argument, 0, 'o'},
{"size", required_argument, 0, 's'},
{"subtitle", required_argument, 0, 'S'},
{"subtitles", required_argument, 0, 'S'},
{"fps", required_argument, 0, 'f'},
{"quality", required_argument, 0, 'q'},
{"quantiser", required_argument, 0, 'Q'},
{"quantiser", required_argument, 0, 'Q'},
{"bitrate", required_argument, 0, 'b'},
{"arate", required_argument, 0, 1400},
{"progressive", no_argument, 0, 'p'},
{"verbose", no_argument, 0, 'v'},
{"test", no_argument, 0, 't'},
{"enable-encode-stats", no_argument, 0, 1000},
{"enable-rcf", no_argument, 0, 1100},
{"ictcp", no_argument, 0, 1300},
{"help", no_argument, 0, '?'},
{0, 0, 0, 0}
};
int option_index = 0;
int c;
while ((c = getopt_long(argc, argv, "i:o:s:S:w:h:f:q:b:Q:pvt", long_options, &option_index)) != -1) {
switch (c) {
case 'i':
enc->input_file = strdup(optarg);
break;
case 'o':
enc->output_file = strdup(optarg);
enc->output_to_stdout = (strcmp(optarg, "-") == 0);
break;
case 's':
if (!parse_resolution(optarg, &enc->width, &enc->height)) {
fprintf(stderr, "Invalid resolution format: %s\n", optarg);
cleanup_encoder(enc);
return 1;
}
break;
case 'S':
enc->subtitle_file = strdup(optarg);
break;
case 'w':
enc->width = atoi(optarg);
break;
case 'h':
enc->height = atoi(optarg);
break;
case 'f':
enc->output_fps = atoi(optarg);
enc->is_ntsc_framerate = 0;
if (enc->output_fps <= 0) {
fprintf(stderr, "Invalid FPS: %d\n", enc->output_fps);
cleanup_encoder(enc);
return 1;
}
break;
case 'q':
int qi = atoi(optarg);
if (qi < 0 || qi > 5) {
fprintf(stderr, "Invalid quality index: %d\nUse value between 0 and 4.\n", qi);
cleanup_encoder(enc);
return 1;
}
enc->qualityIndex = qi;
enc->qualityY = QUALITY_Y[enc->qualityIndex];
enc->qualityCo = QUALITY_CO[enc->qualityIndex];
enc->qualityCg = enc->qualityCo >> 1; // bitshift instead of division so it would round up
break;
case 'b':
enc->target_bitrate_kbps = atoi(optarg);
if (enc->target_bitrate_kbps > 0) {
enc->bitrate_mode = 1; // Enable bitrate control
}
break;
case 'p':
enc->progressive_mode = 1;
break;
case 'v':
enc->verbose = 1;
break;
case 't':
test_mode = 1;
break;
case 1000: // --enable-encode-stats
enc->stats_mode = 1;
break;
case 1100: // --enable-rcf
enc->disable_rcf = 0;
break;
case 1300: // --ictcp
enc->ictcp_mode = 1;
break;
case 1400: // --arate
{
int bitrate = atoi(optarg);
int valid_bitrate = validate_mp2_bitrate(bitrate);
if (valid_bitrate == 0) {
fprintf(stderr, "Error: Invalid MP2 bitrate %d. Valid values are: ", bitrate);
for (int i = 0; i < sizeof(MP2_VALID_BITRATES) / sizeof(int); i++) {
fprintf(stderr, "%d%s", MP2_VALID_BITRATES[i],
(i < sizeof(MP2_VALID_BITRATES) / sizeof(int) - 1) ? ", " : "\n");
}
cleanup_encoder(enc);
return 1;
}
enc->audio_bitrate = valid_bitrate;
}
break;
case 0:
if (strcmp(long_options[option_index].name, "help") == 0) {
show_usage(argv[0]);
cleanup_encoder(enc);
return 0;
}
break;
case 'Q':
enc->qualityY = CLAMP(atoi(optarg), 0, 100);
enc->qualityCo = enc->qualityY;
enc->qualityCg = (enc->qualityY == 100) ? enc->qualityY : enc->qualityCo >> 1;
break;
default:
show_usage(argv[0]);
cleanup_encoder(enc);
return 1;
}
}
// halve the internal representation of frame height
if (!enc->progressive_mode) {
enc->height /= 2;
}
if (enc->ictcp_mode) {
// ICtCp: Ct and Cp have different characteristics than YCoCg Co/Cg
// Cp channel now uses specialised quantisation table, so moderate quality is fine
int base_chroma_quality = enc->qualityCo;
enc->qualityCo = base_chroma_quality; // Ct channel: keep original Co quantisation
enc->qualityCg = base_chroma_quality; // Cp channel: same quality since Q_Cp_8 handles detail preservation
}
if (!test_mode && (!enc->input_file || !enc->output_file)) {
fprintf(stderr, "Input and output files are required (unless using --test mode)\n");
show_usage(argv[0]);
cleanup_encoder(enc);
return 1;
}
if (!enc->output_file) {
fprintf(stderr, "Output file is required\n");
show_usage(argv[0]);
cleanup_encoder(enc);
return 1;
}
// Handle test mode or real video
if (test_mode) {
// Test mode: generate solid colour frames
enc->fps = 1;
enc->output_fps = 1;
enc->total_frames = 15;
enc->has_audio = 0;
printf("Test mode: Generating 15 solid colour frames\n");
} else {
// Get video metadata and start FFmpeg processes
printf("Retrieving video metadata...\n");
if (!get_video_metadata(enc)) {
fprintf(stderr, "Failed to get video metadata\n");
cleanup_encoder(enc);
return 1;
}
}
// Load subtitle file if specified
printf("Loading subtitles...\n");
if (enc->subtitle_file) {
int format = detect_subtitle_format(enc->subtitle_file);
const char *format_name = (format == 1) ? "SAMI" : "SubRip";
enc->subtitle_list = parse_subtitle_file(enc->subtitle_file, enc->output_fps);
if (enc->subtitle_list) {
enc->has_subtitles = 1;
enc->current_subtitle = enc->subtitle_list;
if (enc->verbose) {
printf("Loaded %s subtitles from: %s\n", format_name, enc->subtitle_file);
}
} else {
fprintf(stderr, "Failed to parse %s subtitle file: %s\n", format_name, enc->subtitle_file);
// Continue without subtitles
}
}
// Allocate buffers
if (!alloc_encoder_buffers(enc)) {
fprintf(stderr, "Failed to allocate encoder buffers\n");
cleanup_encoder(enc);
return 1;
}
// Start FFmpeg processes (only for real video mode)
if (!test_mode) {
// Start FFmpeg video conversion
if (!start_video_conversion(enc)) {
fprintf(stderr, "Failed to start video conversion\n");
cleanup_encoder(enc);
return 1;
}
// Start audio conversion (if audio present)
if (!start_audio_conversion(enc)) {
fprintf(stderr, "Warning: Audio conversion failed\n");
enc->has_audio = 0;
}
}
// Open output
FILE *output = enc->output_to_stdout ? stdout : fopen(enc->output_file, "wb");
if (!output) {
perror("Failed to open output file");
cleanup_encoder(enc);
return 1;
}
// Write TEV header
write_tev_header(output, enc);
// Write all subtitles upfront in SSF-TC format (before first frame)
if (enc->has_subtitles) {
write_all_subtitles_tc(enc, output);
}
gettimeofday(&enc->start_time, NULL);
printf("Encoding video with %s 4:2:0 format...\n", enc->ictcp_mode ? "ICtCp" : "YCoCg-R");
if (enc->output_fps != enc->fps) {
printf("Frame rate conversion enabled: %d fps output\n", enc->output_fps);
}
if (enc->bitrate_mode > 0) {
printf("Bitrate control enabled: targeting %d kbps\n", enc->target_bitrate_kbps);
} else {
printf("Quality mode: q=%d\n", enc->qualityIndex);
printf("Quantiser levels: %d, %d, %d\n", enc->qualityY, enc->qualityCo, enc->qualityCg);
}
// Process frames (read until EOF from FFmpeg, or frame limit in test mode)
int frame_count = 0;
int continue_encoding = 1;
while (continue_encoding) {
if (test_mode) {
// Test mode has a fixed frame count
if (frame_count >= enc->total_frames) {
continue_encoding = 0;
break;
}
// Generate test frame with solid colours
size_t rgb_size = enc->width * enc->height * 3;
uint8_t test_r = 0, test_g = 0, test_b = 0;
const char* colour_name = "unknown";
switch (frame_count) {
case 0: test_r = 0; test_g = 0; test_b = 0; colour_name = "black"; break;
case 1: test_r = 127; test_g = 127; test_b = 127; colour_name = "grey"; break;
case 2: test_r = 255; test_g = 255; test_b = 255; colour_name = "white"; break;
case 3: test_r = 127; test_g = 0; test_b = 0; colour_name = "half red"; break;
case 4: test_r = 127; test_g = 127; test_b = 0; colour_name = "half yellow"; break;
case 5: test_r = 0; test_g = 127; test_b = 0; colour_name = "half green"; break;
case 6: test_r = 0; test_g = 127; test_b = 127; colour_name = "half cyan"; break;
case 7: test_r = 0; test_g = 0; test_b = 127; colour_name = "half blue"; break;
case 8: test_r = 127; test_g = 0; test_b = 127; colour_name = "half magenta"; break;
case 9: test_r = 255; test_g = 0; test_b = 0; colour_name = "red"; break;
case 10: test_r = 255; test_g = 255; test_b = 0; colour_name = "yellow"; break;
case 11: test_r = 0; test_g = 255; test_b = 0; colour_name = "green"; break;
case 12: test_r = 0; test_g = 255; test_b = 255; colour_name = "cyan"; break;
case 13: test_r = 0; test_g = 0; test_b = 255; colour_name = "blue"; break;
case 14: test_r = 255; test_g = 0; test_b = 255; colour_name = "magenta"; break;
}
// Fill entire frame with solid colour
for (size_t i = 0; i < rgb_size; i += 3) {
enc->current_rgb[i] = test_r;
enc->current_rgb[i + 1] = test_g;
enc->current_rgb[i + 2] = test_b;
}
printf("Frame %d: %s (%d,%d,%d)\n", frame_count, colour_name, test_r, test_g, test_b);
// Test YCoCg-R conversion
double y_test, co_test, cg_test;
rgb_to_colour_space(enc, test_r, test_g, test_b, &y_test, &co_test, &cg_test);
printf(" %s: Y=%.3f Co=%.3f Cg=%.3f\n", enc->ictcp_mode ? "ICtCp" : "YCoCg", y_test, co_test, cg_test);
// Test reverse conversion
uint8_t r_rev, g_rev, b_rev;
colour_space_to_rgb(enc, y_test, co_test, cg_test, &r_rev, &g_rev, &b_rev);
printf(" Reverse: R=%d G=%d B=%d\n", r_rev, g_rev, b_rev);
} else {
// Read RGB data directly from FFmpeg pipe
// height-halving is already done on the encoder initialisation
int frame_height = enc->height;
size_t rgb_size = enc->width * frame_height * 3;
size_t bytes_read = fread(enc->current_rgb, 1, rgb_size, enc->ffmpeg_video_pipe);
if (bytes_read != rgb_size) {
if (enc->verbose) {
printf("Frame %d: Expected %zu bytes, got %zu bytes\n", frame_count, rgb_size, bytes_read);
if (feof(enc->ffmpeg_video_pipe)) {
printf("FFmpeg pipe reached end of file\n");
}
if (ferror(enc->ffmpeg_video_pipe)) {
printf("FFmpeg pipe error occurred\n");
}
}
continue_encoding = 0;
break; // End of video or error
}
// In interlaced mode, FFmpeg separatefields filter already provides field-separated frames
// Each frame from FFmpeg is now a single field at half height
// Frame parity: even frames (0,2,4...) = bottom fields, odd frames (1,3,5...) = top fields
}
// Process audio for this frame
process_audio(enc, frame_count, output);
// Note: Subtitles are now written upfront in SSF-TC format (see write_all_subtitles_tc)
// process_subtitles() is no longer called here
// Encode frame
// Pass field parity for interlaced mode, -1 for progressive mode
int frame_field_parity = enc->progressive_mode ? -1 : (frame_count % 2);
if (!encode_frame(enc, output, frame_count, frame_field_parity)) {
fprintf(stderr, "Failed to encode frame %d\n", frame_count);
break;
}
else {
// Write a sync packet only after a video is been coded
uint8_t sync_packet = TEV_PACKET_SYNC;
fwrite(&sync_packet, 1, 1, output);
sync_packet_count++;
}
frame_count++;
if (enc->verbose || frame_count % 30 == 0) {
struct timeval now;
gettimeofday(&now, NULL);
double elapsed = (now.tv_sec - enc->start_time.tv_sec) +
(now.tv_usec - enc->start_time.tv_usec) / 1000000.0;
double fps = frame_count / elapsed;
printf("Encoded frame %d (%.1f fps)\n", frame_count, fps);
}
}
// Update actual frame count in encoder struct
enc->total_frames = frame_count;
// Update header with actual frame count (seek back to header position)
if (!enc->output_to_stdout) {
long current_pos = ftell(output);
fseek(output, 14, SEEK_SET); // Offset of total_frames field in header
uint32_t actual_frames = frame_count;
fwrite(&actual_frames, 4, 1, output);
fseek(output, current_pos, SEEK_SET); // Restore position
if (enc->verbose) {
printf("Updated header with actual frame count: %d\n", frame_count);
}
fclose(output);
}
// Final statistics
struct timeval end_time;
gettimeofday(&end_time, NULL);
double total_time = (end_time.tv_sec - enc->start_time.tv_sec) +
(end_time.tv_usec - enc->start_time.tv_usec) / 1000000.0;
printf("\nEncoding complete!\n");
printf(" Frames encoded: %d\n", frame_count);
printf(" Framerate: %d\n", enc->output_fps);
printf(" Output size: %zu bytes\n", enc->total_output_bytes);
printf(" Encoding time: %.2fs (%.1f fps)\n", total_time, frame_count / total_time);
printf(" Block statistics: INTRA=%d, INTER=%d, MOTION=%d, SKIP=%d\n",
enc->blocks_intra, enc->blocks_inter, enc->blocks_motion, enc->blocks_skip);
// Print complexity statistics if enabled
calculate_complexity_stats(enc);
cleanup_encoder(enc);
return 0;
}
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