curioustorvald/tsvm
1
0
Fork 0
mirror of https://github.com/curioustorvald/tsvm.git synced 2026-03-07 11:51:49 +09:00
Code Issues Packages Projects Releases Wiki Activity

TAV-DT: more format revision

Browse Source
This commit is contained in:
minjaesong
2025-12-17 03:20:19 +09:00
parent ca037c8e74
commit e893ca2df5
3 changed files with 278 additions and 100 deletions
Download Patch File Download Diff File Expand all files Collapse all files

23
terranmon.txt
View File

@@ -1649,25 +1649,30 @@ start of the next packet
uint32 Total packet size (sum of TAD packet and TAV packet size) uint32 Total packet size (sum of TAD packet and TAV packet size)
uint64 Timecode in nanoseconds uint64 Timecode in nanoseconds
uint32 Offset to video packet uint32 Offset to video packet
uint32 CRC-32 of [sync pattern + framerate + flags + reserved + total packet size + timecode + offset] uint32 Reserved (zero-fill)
<packet header end; encoded with rate 1/2 LDPC> uint32 CRC-32 of [sync pattern + above]
<packet header end; encoded with rate 256/512 LDPC>
bytes TAD with forward error correction bytes TAD with forward error correction
<TAD header start> <TAD header start>
uint16 Sample Count uint16 Sample Count
uint8 Quantiser Bits uint8 Quantiser Bits
uint16 Reserved (zero-fill)
uint32 Compressed Size uint32 Compressed Size
uint24 Reed-Solomon Block Count uint24 Reed-Solomon Block Count
<TAD chunk header end; encoded with rate 1/2 LDPC> uint32 CRC-32 of above
<TAD chunk header end; encoded with rate 128/256 LDPC>
<Reed-Solomon (255,223) block start> <Reed-Solomon (255,223) block start>
bytes TAD (EZBC, no Zstd) bytes TAD (EZBC, no Zstd)
bytes Parity for TAD bytes Parity for TAD
<Reed-Solomon (255,223) block end> <Reed-Solomon (255,223) block end>
bytes TAV with forward error correction bytes TAV with forward error correction
<TAV header start> <TAV header start>
uint32 TAV header sync pattern (0xA3F7C91E)
uint8 GOP Size (number of frames in this GOP) uint8 GOP Size (number of frames in this GOP)
uint32 Compressed Size uint32 Compressed Size
uint24 Reed-Solomon Block Count uint24 Reed-Solomon Block Count
<TAV header end; encoded with rate 1/2 LDPC> uint32 CRC-32 of above
<TAV header end; encoded with rate 128/256 LDPC>
<Reed-Solomon (255,223) block start> <Reed-Solomon (255,223) block start>
bytes TAV (EZBC, no Zstd) bytes TAV (EZBC, no Zstd)
bytes Parity for TAV bytes Parity for TAV
@@ -1679,6 +1684,8 @@ start of the next packet
Q2. What to do when payload is smaller than RS block capacity? Q2. What to do when payload is smaller than RS block capacity?
A2. Fill with zero. It shouldn't affect Zstd, and compressed size is already specified, so they complement each other. A2. Fill with zero. It shouldn't affect Zstd, and compressed size is already specified, so they complement each other.
When decoding, reserved areas must be filled with zero before the actual decoding.
# How to sync to the stream # How to sync to the stream
1. Find a sync pattern 1. Find a sync pattern
2. Read remaining 8 bytes -> concatenate sync with what has been read 2. Read remaining 8 bytes -> concatenate sync with what has been read
@@ -1703,7 +1710,13 @@ On the stream position where the sync pattern is supposed to be:
### Stage 2 ### Stage 2
1. Further substitute the framerate, flags, timecode to the last known value (as these values rarely change mid-stream; timecode must be incremented appropriately. e.g. FPS=16, last known timecode=5.0, packets missed so far=4, then assumed timecode is 5.0 + 4 + 1 = 10.0) 1. Further substitute the framerate, flags, timecode to the last known value (as these values rarely change mid-stream; timecode must be incremented appropriately. e.g. FPS=16, last known timecode=5.0, packets missed so far=4, then assumed timecode is 5.0 + 4 + 1 = 10.0)
2. Re-calculate CRC. If match, sync. If not, soft sync recovery is failed, and discard the packet 2. Re-calculate CRC. If match, sync. If not, head to the next stage
### Stage 3 (mostly throwaway efforts)
1. Search for 0xA3F7C91E or next sync pattern
2. If 0xA3F7C91E is found, try to decode the subpacket by verifying header with CRC; if next sync pattern is found, sync to that packet.
3. If successful, sync. If not, soft sync recovery is failed, and discard the packet
Note: If CRC is unmatched, the packet MUST be discarded, as the header content cannot be trusted if all soft recovery stages have failed Note: If CRC is unmatched, the packet MUST be discarded, as the header content cannot be trusted if all soft recovery stages have failed

238
video_encoder/src/decoder_tav_dt.c
View File

@@ -9,19 +9,22 @@
* - Mandatory TAD audio * - Mandatory TAD audio
* - LDPC rate 1/2 for headers, Reed-Solomon (255,223) for payloads * - LDPC rate 1/2 for headers, Reed-Solomon (255,223) for payloads
* *
* Packet structure (revised 2025-12-15): * Packet structure (revised 2025-12-17):
* - Main header: 28 bytes → 56 bytes LDPC encoded * - Main header: 32 bytes raw (256 bits) -> 64 bytes LDPC encoded (512 bits, rate 256/512)
* Layout: sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + timecode(8) + offset(4) + crc(4) * Layout: sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + timecode(8) + offset(4) + reserved(4) + crc(4)
* CRC covers bytes 0-23 (everything except CRC itself) * CRC covers bytes 0-27 (everything except CRC itself)
* - TAD subpacket: header (10→20 bytes LDPC) + RS-encoded payload * - TAD subpacket: header 16 bytes raw (128 bits) -> 32 bytes LDPC (256 bits, rate 128/256), + RS-encoded payload
* - TAV subpacket: header (8→16 bytes LDPC) + RS-encoded payload * Layout: sample_count(2) + quant_bits(1) + reserved(2) + compressed_size(4) + rs_block_count(3) + crc(4)
* - TAV subpacket: header 16 bytes raw (128 bits) -> 32 bytes LDPC (256 bits, rate 128/256), + RS-encoded payload
* Layout: sync(4) + gop_size(1) + compressed_size(4) + rs_block_count(3) + crc(4)
* - No packet type bytes - always audio then video * - No packet type bytes - always audio then video
* *
* Features (revised 2025-12-15): * Features (revised 2025-12-17):
* - Soft Sync Recovery: Attempts to recover corrupted headers using known values * - Soft Sync Recovery: Attempts to recover corrupted headers using known values
* - Stage 3 recovery uses TAV subpacket sync pattern (0xA3F7C91E) to locate video data
* *
* Created by CuriousTorvald and Claude on 2025-12-09. * Created by CuriousTorvald and Claude on 2025-12-09.
* Revised 2025-12-15 for updated TAV-DT specification (CRC over timecode+offset, Soft Sync Recovery). * Revised 2025-12-17 for power-of-two header sizes, subpacket CRCs, and TAV subpacket sync.
*/ */
#define _POSIX_C_SOURCE 200809L #define _POSIX_C_SOURCE 200809L
@@ -63,10 +66,15 @@
#define DT_SPATIAL_LEVELS 4 #define DT_SPATIAL_LEVELS 4
#define DT_TEMPORAL_LEVELS 2 #define DT_TEMPORAL_LEVELS 2
// Header sizes (before LDPC encoding) // Header sizes (before LDPC encoding) - revised 2025-12-17
#define DT_MAIN_HEADER_SIZE 28 // sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + crc(4) + timecode(8) + offset(4) // LDPC rates are specified in bits: 256/512 = 256 bits raw -> 512 bits encoded
#define DT_TAD_HEADER_SIZE 10 // sample_count(2) + quant_bits(1) + compressed_size(4) + rs_block_count(3) // Converted to bytes: 32 -> 64 bytes, 16 -> 32 bytes
#define DT_TAV_HEADER_SIZE 8 // gop_size(1) + compressed_size(4) + rs_block_count(3) #define DT_MAIN_HEADER_SIZE 32 // sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + timecode(8) + offset(4) + reserved(4) + crc(4)
#define DT_TAD_HEADER_SIZE 16 // sample_count(2) + quant_bits(1) + reserved(2) + compressed_size(4) + rs_block_count(3) + crc(4)
#define DT_TAV_HEADER_SIZE 16 // sync(4) + gop_size(1) + compressed_size(4) + rs_block_count(3) + crc(4)
// TAV subpacket sync pattern (big endian)
#define TAV_SUBPACKET_SYNC 0xA3F7C91E
// Quality level to quantiser mapping (must match encoder) // Quality level to quantiser mapping (must match encoder)
static const int QUALITY_Y[] = {79, 47, 23, 11, 5, 2}; static const int QUALITY_Y[] = {79, 47, 23, 11, 5, 2};
@@ -453,14 +461,15 @@ typedef struct {
*/ */
static int attempt_soft_sync_recovery(dt_decoder_t *dec, uint8_t *decoded_header, static int attempt_soft_sync_recovery(dt_decoder_t *dec, uint8_t *decoded_header,
dt_packet_header_t *header __attribute__((unused))) { dt_packet_header_t *header __attribute__((unused))) {
// CRC is now at offset 28-31 (revised layout 2025-12-17)
uint32_t stored_crc; uint32_t stored_crc;
memcpy(&stored_crc, decoded_header + 24, 4); memcpy(&stored_crc, decoded_header + 28, 4);
// Get the expected sync pattern (NTSC or PAL based on first packet) // Get the expected sync pattern (NTSC or PAL based on first packet)
uint32_t expected_sync = dec->is_pal ? TAV_DT_SYNC_PAL : TAV_DT_SYNC_NTSC; uint32_t expected_sync = dec->is_pal ? TAV_DT_SYNC_PAL : TAV_DT_SYNC_NTSC;
// === Stage 1 === // === Stage 1 ===
// Substitute sync pattern and zero-fill reserved // Substitute sync pattern and zero-fill reserved fields
uint8_t recovery_header[DT_MAIN_HEADER_SIZE]; uint8_t recovery_header[DT_MAIN_HEADER_SIZE];
memcpy(recovery_header, decoded_header, DT_MAIN_HEADER_SIZE); memcpy(recovery_header, decoded_header, DT_MAIN_HEADER_SIZE);
@@ -470,12 +479,16 @@ static int attempt_soft_sync_recovery(dt_decoder_t *dec, uint8_t *decoded_header
recovery_header[2] = (expected_sync >> 8) & 0xFF; recovery_header[2] = (expected_sync >> 8) & 0xFF;
recovery_header[3] = expected_sync & 0xFF; recovery_header[3] = expected_sync & 0xFF;
// Zero-fill reserved // Zero-fill reserved fields (offset 6-7 and 24-27)
recovery_header[6] = 0; recovery_header[6] = 0;
recovery_header[7] = 0; recovery_header[7] = 0;
recovery_header[24] = 0;
recovery_header[25] = 0;
recovery_header[26] = 0;
recovery_header[27] = 0;
// Recalculate CRC over bytes 0-23 // Recalculate CRC over bytes 0-27
uint32_t calculated_crc = calculate_crc32(recovery_header, 24); uint32_t calculated_crc = calculate_crc32(recovery_header, 28);
if (calculated_crc == stored_crc) { if (calculated_crc == stored_crc) {
if (dec->verbose) { if (dec->verbose) {
printf(" Soft Sync Recovery Stage 1: SUCCESS (sync/reserved corrected)\n"); printf(" Soft Sync Recovery Stage 1: SUCCESS (sync/reserved corrected)\n");
@@ -502,7 +515,7 @@ static int attempt_soft_sync_recovery(dt_decoder_t *dec, uint8_t *decoded_header
memcpy(recovery_header + 12, &expected_timecode, 8); memcpy(recovery_header + 12, &expected_timecode, 8);
// Recalculate CRC // Recalculate CRC
calculated_crc = calculate_crc32(recovery_header, 24); calculated_crc = calculate_crc32(recovery_header, 28);
if (calculated_crc == stored_crc) { if (calculated_crc == stored_crc) {
if (dec->verbose) { if (dec->verbose) {
printf(" Soft Sync Recovery Stage 2: SUCCESS (sync/reserved/fps/flags/timecode corrected)\n"); printf(" Soft Sync Recovery Stage 2: SUCCESS (sync/reserved/fps/flags/timecode corrected)\n");
@@ -515,6 +528,11 @@ static int attempt_soft_sync_recovery(dt_decoder_t *dec, uint8_t *decoded_header
} }
} }
// === Stage 3 ===
// Note: Stage 3 (searching for TAV subpacket sync 0xA3F7C91E) would require
// file seeking and is implemented separately in find_sync_pattern fallback.
// This function only handles header data recovery.
if (dec->verbose) { if (dec->verbose) {
fprintf(stderr, " Soft Sync Recovery: FAILED (all stages exhausted)\n"); fprintf(stderr, " Soft Sync Recovery: FAILED (all stages exhausted)\n");
} }
@@ -522,13 +540,13 @@ static int attempt_soft_sync_recovery(dt_decoder_t *dec, uint8_t *decoded_header
} }
static int read_and_decode_header(dt_decoder_t *dec, dt_packet_header_t *header) { static int read_and_decode_header(dt_decoder_t *dec, dt_packet_header_t *header) {
// Read LDPC-encoded header (56 bytes = 28 bytes * 2) // Read LDPC-encoded header (64 bytes = 32 bytes * 2, rate 256/512 bits)
uint8_t encoded_header[DT_MAIN_HEADER_SIZE * 2]; uint8_t encoded_header[DT_MAIN_HEADER_SIZE * 2];
size_t bytes_read = fread(encoded_header, 1, DT_MAIN_HEADER_SIZE * 2, dec->input_fp); size_t bytes_read = fread(encoded_header, 1, DT_MAIN_HEADER_SIZE * 2, dec->input_fp);
if (bytes_read < DT_MAIN_HEADER_SIZE * 2) return -1; if (bytes_read < DT_MAIN_HEADER_SIZE * 2) return -1;
dec->bytes_read += DT_MAIN_HEADER_SIZE * 2; dec->bytes_read += DT_MAIN_HEADER_SIZE * 2;
// LDPC decode header (56 bytes -> 28 bytes) // LDPC decode header (64 bytes -> 32 bytes)
uint8_t decoded_header[DT_MAIN_HEADER_SIZE]; uint8_t decoded_header[DT_MAIN_HEADER_SIZE];
int ldpc_result = ldpc_decode(encoded_header, DT_MAIN_HEADER_SIZE * 2, decoded_header); int ldpc_result = ldpc_decode(encoded_header, DT_MAIN_HEADER_SIZE * 2, decoded_header);
if (ldpc_result < 0) { if (ldpc_result < 0) {
@@ -541,17 +559,18 @@ static int read_and_decode_header(dt_decoder_t *dec, dt_packet_header_t *header)
dec->fec_corrections++; dec->fec_corrections++;
} }
// Parse header fields (revised layout 2025-12-15) // Parse header fields (revised layout 2025-12-17)
// Layout: sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + timecode(8) + offset(4) + crc(4) // Layout: sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + timecode(8) + offset(4) + reserved(4) + crc(4)
header->sync_pattern = ((uint32_t)decoded_header[0] << 24) | ((uint32_t)decoded_header[1] << 16) | header->sync_pattern = ((uint32_t)decoded_header[0] << 24) | ((uint32_t)decoded_header[1] << 16) |
((uint32_t)decoded_header[2] << 8) | decoded_header[3]; ((uint32_t)decoded_header[2] << 8) | decoded_header[3];
header->framerate = decoded_header[4]; header->framerate = decoded_header[4];
header->flags = decoded_header[5]; header->flags = decoded_header[5];
header->reserved = decoded_header[6] | ((uint16_t)decoded_header[7] << 8); header->reserved = decoded_header[6] | ((uint16_t)decoded_header[7] << 8);
memcpy(&header->packet_size, decoded_header + 8, 4); memcpy(&header->packet_size, decoded_header + 8, 4);
memcpy(&header->timecode_ns, decoded_header + 12, 8); // Now at offset 12 memcpy(&header->timecode_ns, decoded_header + 12, 8); // At offset 12
memcpy(&header->offset_to_video, decoded_header + 20, 4); // Now at offset 20 memcpy(&header->offset_to_video, decoded_header + 20, 4); // At offset 20
memcpy(&header->crc32, decoded_header + 24, 4); // Now at offset 24 // Reserved at offset 24-27 (ignored)
memcpy(&header->crc32, decoded_header + 28, 4); // At offset 28
// Verify sync pattern // Verify sync pattern
int sync_valid = (header->sync_pattern == TAV_DT_SYNC_NTSC || header->sync_pattern == TAV_DT_SYNC_PAL); int sync_valid = (header->sync_pattern == TAV_DT_SYNC_NTSC || header->sync_pattern == TAV_DT_SYNC_PAL);
@@ -559,8 +578,8 @@ static int read_and_decode_header(dt_decoder_t *dec, dt_packet_header_t *header)
fprintf(stderr, "Warning: Invalid sync pattern 0x%08X\n", header->sync_pattern); fprintf(stderr, "Warning: Invalid sync pattern 0x%08X\n", header->sync_pattern);
} }
// Verify CRC-32 (covers bytes 0-23: sync + fps + flags + reserved + size + timecode + offset) // Verify CRC-32 (covers bytes 0-27: sync + fps + flags + reserved + size + timecode + offset + reserved)
uint32_t calculated_crc = calculate_crc32(decoded_header, 24); uint32_t calculated_crc = calculate_crc32(decoded_header, 28);
int crc_valid = (calculated_crc == header->crc32); int crc_valid = (calculated_crc == header->crc32);
if (!crc_valid) { if (!crc_valid) {
@@ -571,7 +590,7 @@ static int read_and_decode_header(dt_decoder_t *dec, dt_packet_header_t *header)
// Attempt Soft Sync Recovery // Attempt Soft Sync Recovery
if (dec->packets_processed > 0 && attempt_soft_sync_recovery(dec, decoded_header, header)) { if (dec->packets_processed > 0 && attempt_soft_sync_recovery(dec, decoded_header, header)) {
// Re-parse header from recovered data // Re-parse header from recovered data (revised layout 2025-12-17)
header->sync_pattern = ((uint32_t)decoded_header[0] << 24) | ((uint32_t)decoded_header[1] << 16) | header->sync_pattern = ((uint32_t)decoded_header[0] << 24) | ((uint32_t)decoded_header[1] << 16) |
((uint32_t)decoded_header[2] << 8) | decoded_header[3]; ((uint32_t)decoded_header[2] << 8) | decoded_header[3];
header->framerate = decoded_header[4]; header->framerate = decoded_header[4];
@@ -580,7 +599,8 @@ static int read_and_decode_header(dt_decoder_t *dec, dt_packet_header_t *header)
memcpy(&header->packet_size, decoded_header + 8, 4); memcpy(&header->packet_size, decoded_header + 8, 4);
memcpy(&header->timecode_ns, decoded_header + 12, 8); memcpy(&header->timecode_ns, decoded_header + 12, 8);
memcpy(&header->offset_to_video, decoded_header + 20, 4); memcpy(&header->offset_to_video, decoded_header + 20, 4);
memcpy(&header->crc32, decoded_header + 24, 4); // Reserved at offset 24-27 (ignored)
memcpy(&header->crc32, decoded_header + 28, 4);
crc_valid = 1; // Recovery succeeded crc_valid = 1; // Recovery succeeded
} else { } else {
dec->crc_errors++; dec->crc_errors++;
@@ -851,12 +871,12 @@ static int decode_audio_subpacket(dt_decoder_t *dec, const uint8_t *data, size_t
size_t *consumed, size_t *samples_written) { size_t *consumed, size_t *samples_written) {
*samples_written = 0; *samples_written = 0;
// Minimum: 20 byte LDPC header // Minimum: 32 byte LDPC header (16 bytes * 2, rate 128/256 bits)
if (data_len < DT_TAD_HEADER_SIZE * 2) return -1; if (data_len < DT_TAD_HEADER_SIZE * 2) return -1;
size_t offset = 0; size_t offset = 0;
// LDPC decode TAD header (20 bytes -> 10 bytes) // LDPC decode TAD header (32 bytes -> 16 bytes)
uint8_t decoded_tad_header[DT_TAD_HEADER_SIZE]; uint8_t decoded_tad_header[DT_TAD_HEADER_SIZE];
int ldpc_result = ldpc_decode(data + offset, DT_TAD_HEADER_SIZE * 2, decoded_tad_header); int ldpc_result = ldpc_decode(data + offset, DT_TAD_HEADER_SIZE * 2, decoded_tad_header);
if (ldpc_result < 0) { if (ldpc_result < 0) {
@@ -869,19 +889,38 @@ static int decode_audio_subpacket(dt_decoder_t *dec, const uint8_t *data, size_t
} }
offset += DT_TAD_HEADER_SIZE * 2; offset += DT_TAD_HEADER_SIZE * 2;
// Parse TAD header // Parse TAD header (revised layout 2025-12-17)
// Layout: sample_count(2) + quant_bits(1) + reserved(2) + compressed_size(4) + rs_block_count(3) + crc(4)
uint16_t sample_count; uint16_t sample_count;
uint8_t quant_bits; uint8_t quant_bits;
uint32_t compressed_size; uint32_t compressed_size;
uint32_t rs_block_count; uint32_t rs_block_count;
uint32_t stored_crc;
memcpy(&sample_count, decoded_tad_header, 2); memcpy(&sample_count, decoded_tad_header, 2);
quant_bits = decoded_tad_header[2]; quant_bits = decoded_tad_header[2];
memcpy(&compressed_size, decoded_tad_header + 3, 4); // Reserved at offset 3-4 (ignored)
// uint24 rs_block_count (little endian) memcpy(&compressed_size, decoded_tad_header + 5, 4);
rs_block_count = decoded_tad_header[7] | // uint24 rs_block_count (little endian) at offset 9-11
((uint32_t)decoded_tad_header[8] << 8) | rs_block_count = decoded_tad_header[9] |
((uint32_t)decoded_tad_header[9] << 16); ((uint32_t)decoded_tad_header[10] << 8) |
((uint32_t)decoded_tad_header[11] << 16);
memcpy(&stored_crc, decoded_tad_header + 12, 4);
// Verify CRC-32 (covers bytes 0-11)
uint32_t calculated_crc = calculate_crc32(decoded_tad_header, 12);
int tad_header_valid = (calculated_crc == stored_crc);
if (!tad_header_valid) {
if (dec->verbose) {
fprintf(stderr, "Warning: TAD header CRC mismatch (expected 0x%08X, got 0x%08X) - skipping audio\n",
stored_crc, calculated_crc);
}
dec->crc_errors++;
// Cannot trust header data - skip audio decoding entirely
// Error concealment will insert silence
*consumed = offset;
return -1;
}
if (dec->verbose) { if (dec->verbose) {
printf(" TAD: samples=%u, quant_bits=%u, compressed=%u, rs_blocks=%u\n", printf(" TAD: samples=%u, quant_bits=%u, compressed=%u, rs_blocks=%u\n",
@@ -891,6 +930,18 @@ static int decode_audio_subpacket(dt_decoder_t *dec, const uint8_t *data, size_t
// Calculate RS payload size // Calculate RS payload size
size_t rs_total = rs_block_count * RS_BLOCK_SIZE; size_t rs_total = rs_block_count * RS_BLOCK_SIZE;
// Sanity check: compressed_size must not exceed RS payload capacity
// RS(255,223) means 223 data bytes per 255-byte block
size_t max_data_size = (rs_block_count * RS_DATA_SIZE);
if (compressed_size > max_data_size) {
if (dec->verbose) {
fprintf(stderr, "Warning: TAD compressed_size (%u) exceeds RS capacity (%zu) - skipping audio\n",
compressed_size, max_data_size);
}
*consumed = offset;
return -1;
}
// Handle empty audio packet (no samples in this GOP) // Handle empty audio packet (no samples in this GOP)
if (compressed_size == 0 || rs_block_count == 0 || sample_count == 0) { if (compressed_size == 0 || rs_block_count == 0 || sample_count == 0) {
*consumed = offset; *consumed = offset;
@@ -982,12 +1033,12 @@ static int decode_video_subpacket_mt(dt_decoder_t *dec, const uint8_t *data, siz
size_t *consumed, int *frames_written) { size_t *consumed, int *frames_written) {
*frames_written = 0; *frames_written = 0;
// Minimum: 16 byte LDPC header // Minimum: 32 byte LDPC header (16 bytes * 2, rate 128/256 bits)
if (data_len < DT_TAV_HEADER_SIZE * 2) return -1; if (data_len < DT_TAV_HEADER_SIZE * 2) return -1;
size_t offset = 0; size_t offset = 0;
// LDPC decode TAV header (16 bytes -> 8 bytes) // LDPC decode TAV header (32 bytes -> 16 bytes)
uint8_t decoded_tav_header[DT_TAV_HEADER_SIZE]; uint8_t decoded_tav_header[DT_TAV_HEADER_SIZE];
int ldpc_result = ldpc_decode(data + offset, DT_TAV_HEADER_SIZE * 2, decoded_tav_header); int ldpc_result = ldpc_decode(data + offset, DT_TAV_HEADER_SIZE * 2, decoded_tav_header);
if (ldpc_result < 0) { if (ldpc_result < 0) {
@@ -1000,19 +1051,58 @@ static int decode_video_subpacket_mt(dt_decoder_t *dec, const uint8_t *data, siz
} }
offset += DT_TAV_HEADER_SIZE * 2; offset += DT_TAV_HEADER_SIZE * 2;
// Parse TAV header // Parse TAV header (revised layout 2025-12-17)
uint8_t gop_size = decoded_tav_header[0]; // Layout: sync(4) + gop_size(1) + compressed_size(4) + rs_block_count(3) + crc(4)
uint32_t subpacket_sync = ((uint32_t)decoded_tav_header[0] << 24) |
((uint32_t)decoded_tav_header[1] << 16) |
((uint32_t)decoded_tav_header[2] << 8) |
decoded_tav_header[3];
uint8_t gop_size = decoded_tav_header[4];
uint32_t compressed_size; uint32_t compressed_size;
uint32_t rs_block_count; uint32_t rs_block_count;
uint32_t stored_crc;
memcpy(&compressed_size, decoded_tav_header + 1, 4); memcpy(&compressed_size, decoded_tav_header + 5, 4);
rs_block_count = decoded_tav_header[5] | rs_block_count = decoded_tav_header[9] |
((uint32_t)decoded_tav_header[6] << 8) | ((uint32_t)decoded_tav_header[10] << 8) |
((uint32_t)decoded_tav_header[7] << 16); ((uint32_t)decoded_tav_header[11] << 16);
memcpy(&stored_crc, decoded_tav_header + 12, 4);
// Verify sync pattern and CRC-32 (covers bytes 0-11)
int sync_valid = (subpacket_sync == TAV_SUBPACKET_SYNC);
uint32_t calculated_crc = calculate_crc32(decoded_tav_header, 12);
int crc_valid = (calculated_crc == stored_crc);
if (!sync_valid && dec->verbose) {
fprintf(stderr, "Warning: TAV subpacket sync mismatch (MT) (expected 0x%08X, got 0x%08X)\n",
TAV_SUBPACKET_SYNC, subpacket_sync);
}
if (!crc_valid) {
if (dec->verbose) {
fprintf(stderr, "Warning: TAV header CRC mismatch (MT) (expected 0x%08X, got 0x%08X) - skipping video\n",
stored_crc, calculated_crc);
}
dec->crc_errors++;
// Cannot trust header data - skip video decoding entirely
*consumed = offset;
return -1;
}
// Calculate RS payload size // Calculate RS payload size
size_t rs_total = rs_block_count * RS_BLOCK_SIZE; size_t rs_total = rs_block_count * RS_BLOCK_SIZE;
// Sanity check: compressed_size must not exceed RS payload capacity
size_t max_data_size = (rs_block_count * RS_DATA_SIZE);
if (compressed_size > max_data_size) {
if (dec->verbose) {
fprintf(stderr, "Warning: TAV compressed_size (MT) (%u) exceeds RS capacity (%zu) - skipping video\n",
compressed_size, max_data_size);
}
*consumed = offset;
return -1;
}
if (offset + rs_total > data_len) { if (offset + rs_total > data_len) {
*consumed = data_len; *consumed = data_len;
return -1; // Unrecoverable return -1; // Unrecoverable
@@ -1147,12 +1237,12 @@ static int decode_video_subpacket(dt_decoder_t *dec, const uint8_t *data, size_t
size_t *consumed, int *frames_written) { size_t *consumed, int *frames_written) {
*frames_written = 0; *frames_written = 0;
// Minimum: 16 byte LDPC header // Minimum: 32 byte LDPC header (16 bytes * 2, rate 128/256 bits)
if (data_len < DT_TAV_HEADER_SIZE * 2) return -1; if (data_len < DT_TAV_HEADER_SIZE * 2) return -1;
size_t offset = 0; size_t offset = 0;
// LDPC decode TAV header (16 bytes -> 8 bytes) // LDPC decode TAV header (32 bytes -> 16 bytes)
uint8_t decoded_tav_header[DT_TAV_HEADER_SIZE]; uint8_t decoded_tav_header[DT_TAV_HEADER_SIZE];
int ldpc_result = ldpc_decode(data + offset, DT_TAV_HEADER_SIZE * 2, decoded_tav_header); int ldpc_result = ldpc_decode(data + offset, DT_TAV_HEADER_SIZE * 2, decoded_tav_header);
if (ldpc_result < 0) { if (ldpc_result < 0) {
@@ -1165,16 +1255,45 @@ static int decode_video_subpacket(dt_decoder_t *dec, const uint8_t *data, size_t
} }
offset += DT_TAV_HEADER_SIZE * 2; offset += DT_TAV_HEADER_SIZE * 2;
// Parse TAV header // Parse TAV header (revised layout 2025-12-17)
uint8_t gop_size = decoded_tav_header[0]; // Layout: sync(4) + gop_size(1) + compressed_size(4) + rs_block_count(3) + crc(4)
uint32_t subpacket_sync = ((uint32_t)decoded_tav_header[0] << 24) |
((uint32_t)decoded_tav_header[1] << 16) |
((uint32_t)decoded_tav_header[2] << 8) |
decoded_tav_header[3];
uint8_t gop_size = decoded_tav_header[4];
uint32_t compressed_size; uint32_t compressed_size;
uint32_t rs_block_count; uint32_t rs_block_count;
uint32_t stored_crc;
memcpy(&compressed_size, decoded_tav_header + 1, 4); memcpy(&compressed_size, decoded_tav_header + 5, 4);
// uint24 rs_block_count (little endian) // uint24 rs_block_count (little endian) at offset 9-11
rs_block_count = decoded_tav_header[5] | rs_block_count = decoded_tav_header[9] |
((uint32_t)decoded_tav_header[6] << 8) | ((uint32_t)decoded_tav_header[10] << 8) |
((uint32_t)decoded_tav_header[7] << 16); ((uint32_t)decoded_tav_header[11] << 16);
memcpy(&stored_crc, decoded_tav_header + 12, 4);
// Verify sync pattern and CRC-32 (covers bytes 0-11)
int sync_valid = (subpacket_sync == TAV_SUBPACKET_SYNC);
uint32_t calculated_crc = calculate_crc32(decoded_tav_header, 12);
int crc_valid = (calculated_crc == stored_crc);
if (!sync_valid && dec->verbose) {
fprintf(stderr, "Warning: TAV subpacket sync mismatch (expected 0x%08X, got 0x%08X)\n",
TAV_SUBPACKET_SYNC, subpacket_sync);
}
if (!crc_valid) {
if (dec->verbose) {
fprintf(stderr, "Warning: TAV header CRC mismatch (expected 0x%08X, got 0x%08X) - skipping video\n",
stored_crc, calculated_crc);
}
dec->crc_errors++;
// Cannot trust header data - skip video decoding entirely
// Error concealment will use freeze frame
*consumed = offset;
return -1;
}
if (dec->verbose) { if (dec->verbose) {
printf(" TAV: gop_size=%u, compressed=%u, rs_blocks=%u\n", printf(" TAV: gop_size=%u, compressed=%u, rs_blocks=%u\n",
@@ -1184,6 +1303,17 @@ static int decode_video_subpacket(dt_decoder_t *dec, const uint8_t *data, size_t
// Calculate RS payload size // Calculate RS payload size
size_t rs_total = rs_block_count * RS_BLOCK_SIZE; size_t rs_total = rs_block_count * RS_BLOCK_SIZE;
// Sanity check: compressed_size must not exceed RS payload capacity
size_t max_data_size = (rs_block_count * RS_DATA_SIZE);
if (compressed_size > max_data_size) {
if (dec->verbose) {
fprintf(stderr, "Warning: TAV compressed_size (%u) exceeds RS capacity (%zu) - skipping video\n",
compressed_size, max_data_size);
}
*consumed = offset;
return -1;
}
if (offset + rs_total > data_len) { if (offset + rs_total > data_len) {
if (dec->verbose) { if (dec->verbose) {
fprintf(stderr, "Warning: Video packet truncated\n"); fprintf(stderr, "Warning: Video packet truncated\n");

117
video_encoder/src/encoder_tav_dt.c
View File

@@ -9,16 +9,18 @@
* - Mandatory TAD audio * - Mandatory TAD audio
* - LDPC rate 1/2 for headers, Reed-Solomon (255,223) for payloads * - LDPC rate 1/2 for headers, Reed-Solomon (255,223) for payloads
* *
* Packet structure (revised 2025-12-15): * Packet structure (revised 2025-12-17):
* - Main header: 28 bytes -> 56 bytes LDPC encoded * - Main header: 32 bytes raw (256 bits) -> 64 bytes LDPC encoded (512 bits, rate 256/512)
* Layout: sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + timecode(8) + offset(4) + crc(4) * Layout: sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + timecode(8) + offset(4) + reserved(4) + crc(4)
* CRC covers bytes 0-23 (everything except CRC itself) * CRC covers bytes 0-27 (everything except CRC itself)
* - TAD subpacket: header (10->20 bytes LDPC) + RS-encoded payload * - TAD subpacket: header 16 bytes raw (128 bits) -> 32 bytes LDPC (256 bits, rate 128/256), + RS-encoded payload
* - TAV subpacket: header (8->16 bytes LDPC) + RS-encoded payload * Layout: sample_count(2) + quant_bits(1) + reserved(2) + compressed_size(4) + rs_block_count(3) + crc(4)
* - TAV subpacket: header 16 bytes raw (128 bits) -> 32 bytes LDPC (256 bits, rate 128/256), + RS-encoded payload
* Layout: sync(4) + gop_size(1) + compressed_size(4) + rs_block_count(3) + crc(4)
* - No packet type bytes - always audio then video * - No packet type bytes - always audio then video
* *
* Created by CuriousTorvald and Claude on 2025-12-09. * Created by CuriousTorvald and Claude on 2025-12-09.
* Revised 2025-12-15 for updated TAV-DT specification (CRC now covers timecode and offset). * Revised 2025-12-17 for power-of-two header sizes, subpacket CRCs, and TAV subpacket sync.
*/ */
#define _POSIX_C_SOURCE 200809L #define _POSIX_C_SOURCE 200809L
@@ -61,10 +63,15 @@
#define DT_SPATIAL_LEVELS 4 #define DT_SPATIAL_LEVELS 4
#define DT_TEMPORAL_LEVELS 2 #define DT_TEMPORAL_LEVELS 2
// Header sizes (before LDPC encoding) // Header sizes (before LDPC encoding) - revised 2025-12-17
#define DT_MAIN_HEADER_SIZE 28 // sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + crc(4) + timecode(8) + offset(4) // LDPC rates are specified in bits: 256/512 = 256 bits raw -> 512 bits encoded
#define DT_TAD_HEADER_SIZE 10 // sample_count(2) + quant_bits(1) + compressed_size(4) + rs_block_count(3) // Converted to bytes: 32 -> 64 bytes, 16 -> 32 bytes
#define DT_TAV_HEADER_SIZE 8 // gop_size(1) + compressed_size(4) + rs_block_count(3) #define DT_MAIN_HEADER_SIZE 32 // sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + timecode(8) + offset(4) + reserved(4) + crc(4)
#define DT_TAD_HEADER_SIZE 16 // sample_count(2) + quant_bits(1) + reserved(2) + compressed_size(4) + rs_block_count(3) + crc(4)
#define DT_TAV_HEADER_SIZE 16 // sync(4) + gop_size(1) + compressed_size(4) + rs_block_count(3) + crc(4)
// TAV subpacket sync pattern (big endian)
#define TAV_SUBPACKET_SYNC 0xA3F7C91E
// Quality level to quantiser mapping // Quality level to quantiser mapping
static const int QUALITY_Y[] = {79, 47, 23, 11, 5, 2}; static const int QUALITY_Y[] = {79, 47, 23, 11, 5, 2};
@@ -298,16 +305,19 @@ static int write_packet(dt_encoder_t *enc, uint64_t timecode_ns,
size_t tad_rs_size = tad_rs_blocks * RS_BLOCK_SIZE; size_t tad_rs_size = tad_rs_blocks * RS_BLOCK_SIZE;
size_t tav_rs_size = tav_rs_blocks * RS_BLOCK_SIZE; size_t tav_rs_size = tav_rs_blocks * RS_BLOCK_SIZE;
size_t tad_subpacket_size = DT_TAD_HEADER_SIZE * 2 + tad_rs_size; // LDPC header + RS payload // Subpacket sizes: LDPC header (16->32 bytes) + RS payload
size_t tav_subpacket_size = DT_TAV_HEADER_SIZE * 2 + tav_rs_size; // LDPC header + RS payload size_t tad_subpacket_size = DT_TAD_HEADER_SIZE * 2 + tad_rs_size;
size_t tav_subpacket_size = DT_TAV_HEADER_SIZE * 2 + tav_rs_size;
uint32_t offset_to_video = tad_subpacket_size; uint32_t offset_to_video = tad_subpacket_size;
uint32_t packet_size = tad_subpacket_size + tav_subpacket_size; uint32_t packet_size = tad_subpacket_size + tav_subpacket_size;
// Build main header (28 bytes) // Build main header (32 bytes raw = 256 bits)
// Layout (revised 2025-12-15): sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + timecode(8) + offset(4) + crc(4) // Layout: sync(4) + fps(1) + flags(1) + reserved(2) + size(4) + timecode(8) + offset(4) + reserved(4) + crc(4)
// CRC is calculated over bytes 0-23 (everything except CRC itself) // CRC is calculated over bytes 0-27 (everything except CRC itself)
uint8_t header[DT_MAIN_HEADER_SIZE]; uint8_t header[DT_MAIN_HEADER_SIZE]; // 32 bytes
memset(header, 0, DT_MAIN_HEADER_SIZE);
// Write sync pattern in big-endian (network byte order) // Write sync pattern in big-endian (network byte order)
uint32_t sync = enc->is_pal ? TAV_DT_SYNC_PAL : TAV_DT_SYNC_NTSC; uint32_t sync = enc->is_pal ? TAV_DT_SYNC_PAL : TAV_DT_SYNC_NTSC;
header[0] = (sync >> 24) & 0xFF; header[0] = (sync >> 24) & 0xFF;
@@ -326,54 +336,79 @@ static int write_packet(dt_encoder_t *enc, uint64_t timecode_ns,
uint8_t flags = 0; uint8_t flags = 0;
flags |= (enc->is_interlaced ? 0x01 : 0x00); flags |= (enc->is_interlaced ? 0x01 : 0x00);
flags |= (enc->fps_den == 1001 ? 0x02 : 0x00); flags |= (enc->fps_den == 1001 ? 0x02 : 0x00);
flags |= ((enc->fec_mode & 0x01) << 2); // FEC mode in bit 2
flags |= (enc->quality_index & 0x0F) << 4; flags |= (enc->quality_index & 0x0F) << 4;
header[5] = flags; header[5] = flags;
// Reserved (2 bytes) // Reserved (2 bytes) at offset 6-7
header[6] = 0; header[6] = 0;
header[7] = 0; header[7] = 0;
// Packet size (4 bytes) // Packet size (4 bytes) at offset 8-11
memcpy(header + 8, &packet_size, 4); memcpy(header + 8, &packet_size, 4);
// Timecode (8 bytes) - now at offset 12 // Timecode (8 bytes) at offset 12-19
memcpy(header + 12, &timecode_ns, 8); memcpy(header + 12, &timecode_ns, 8);
// Offset to video (4 bytes) - now at offset 20 // Offset to video (4 bytes) at offset 20-23
memcpy(header + 20, &offset_to_video, 4); memcpy(header + 20, &offset_to_video, 4);
// CRC-32 (4 bytes) - calculated over bytes 0-23 (sync + fps + flags + reserved + size + timecode + offset) // Reserved (4 bytes) at offset 24-27
uint32_t crc = calculate_crc32(header, 24); // Already zero from memset
memcpy(header + 24, &crc, 4);
// LDPC encode main header // CRC-32 (4 bytes) at offset 28-31, calculated over bytes 0-27
uint32_t crc = calculate_crc32(header, 28);
memcpy(header + 28, &crc, 4);
// LDPC encode main header (32 -> 64 bytes, rate 256/512 bits)
uint8_t ldpc_header[DT_MAIN_HEADER_SIZE * 2]; uint8_t ldpc_header[DT_MAIN_HEADER_SIZE * 2];
ldpc_encode(header, DT_MAIN_HEADER_SIZE, ldpc_header); ldpc_encode(header, DT_MAIN_HEADER_SIZE, ldpc_header);
// Build TAD subpacket header (10 bytes) // Build TAD subpacket header (16 bytes raw = 128 bits)
uint8_t tad_header[DT_TAD_HEADER_SIZE]; // Layout: sample_count(2) + quant_bits(1) + reserved(2) + compressed_size(4) + rs_block_count(3) + crc(4)
uint8_t tad_header[DT_TAD_HEADER_SIZE]; // 16 bytes
memset(tad_header, 0, DT_TAD_HEADER_SIZE);
memcpy(tad_header + 0, &audio_samples, 2); memcpy(tad_header + 0, &audio_samples, 2);
tad_header[2] = audio_quant_bits; tad_header[2] = audio_quant_bits;
// Reserved (2 bytes) at offset 3-4
uint32_t tad_compressed_size = tad_size; uint32_t tad_compressed_size = tad_size;
memcpy(tad_header + 3, &tad_compressed_size, 4); memcpy(tad_header + 5, &tad_compressed_size, 4);
// RS block count as uint24 // RS block count as uint24 at offset 9-11
tad_header[7] = tad_rs_blocks & 0xFF; tad_header[9] = tad_rs_blocks & 0xFF;
tad_header[8] = (tad_rs_blocks >> 8) & 0xFF; tad_header[10] = (tad_rs_blocks >> 8) & 0xFF;
tad_header[9] = (tad_rs_blocks >> 16) & 0xFF; tad_header[11] = (tad_rs_blocks >> 16) & 0xFF;
// CRC-32 (4 bytes) at offset 12-15, calculated over bytes 0-11
uint32_t tad_crc = calculate_crc32(tad_header, 12);
memcpy(tad_header + 12, &tad_crc, 4);
// LDPC encode TAD header (16 -> 32 bytes, rate 128/256 bits)
uint8_t ldpc_tad_header[DT_TAD_HEADER_SIZE * 2]; uint8_t ldpc_tad_header[DT_TAD_HEADER_SIZE * 2];
ldpc_encode(tad_header, DT_TAD_HEADER_SIZE, ldpc_tad_header); ldpc_encode(tad_header, DT_TAD_HEADER_SIZE, ldpc_tad_header);
// Build TAV subpacket header (8 bytes) // Build TAV subpacket header (16 bytes raw = 128 bits)
uint8_t tav_header[DT_TAV_HEADER_SIZE]; // Layout: sync(4) + gop_size(1) + compressed_size(4) + rs_block_count(3) + crc(4)
tav_header[0] = gop_size; uint8_t tav_header[DT_TAV_HEADER_SIZE]; // 16 bytes
uint32_t tav_compressed_size = tav_size; memset(tav_header, 0, DT_TAV_HEADER_SIZE);
memcpy(tav_header + 1, &tav_compressed_size, 4);
// RS block count as uint24
tav_header[5] = tav_rs_blocks & 0xFF;
tav_header[6] = (tav_rs_blocks >> 8) & 0xFF;
tav_header[7] = (tav_rs_blocks >> 16) & 0xFF;
// Write TAV subpacket sync pattern in big-endian
tav_header[0] = (TAV_SUBPACKET_SYNC >> 24) & 0xFF;
tav_header[1] = (TAV_SUBPACKET_SYNC >> 16) & 0xFF;
tav_header[2] = (TAV_SUBPACKET_SYNC >> 8) & 0xFF;
tav_header[3] = TAV_SUBPACKET_SYNC & 0xFF;
tav_header[4] = gop_size;
uint32_t tav_compressed_size = tav_size;
memcpy(tav_header + 5, &tav_compressed_size, 4);
// RS block count as uint24 at offset 9-11
tav_header[9] = tav_rs_blocks & 0xFF;
tav_header[10] = (tav_rs_blocks >> 8) & 0xFF;
tav_header[11] = (tav_rs_blocks >> 16) & 0xFF;
// CRC-32 (4 bytes) at offset 12-15, calculated over bytes 0-11
uint32_t tav_crc = calculate_crc32(tav_header, 12);
memcpy(tav_header + 12, &tav_crc, 4);
// LDPC encode TAV header (16 -> 32 bytes, rate 128/256 bits)
uint8_t ldpc_tav_header[DT_TAV_HEADER_SIZE * 2]; uint8_t ldpc_tav_header[DT_TAV_HEADER_SIZE * 2];
ldpc_encode(tav_header, DT_TAV_HEADER_SIZE, ldpc_tav_header); ldpc_encode(tav_header, DT_TAV_HEADER_SIZE, ldpc_tav_header);