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TAV: channel-concatenated coeffs preprocessing

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minjaesong
2025-09-29 14:42:52 +09:00
parent 5012ca4085
commit 1d3d218238
5 changed files with 339 additions and 81 deletions
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95
video_encoder/decoder_tav.c
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@@ -47,6 +47,57 @@ static void postprocess_coefficients(uint8_t *compressed_data, int coeff_count,
}
}
// Decoder: reconstruct coefficients from concatenated significance maps
// Layout: [Y_map][Co_map][Cg_map][Y_vals][Co_vals][Cg_vals]
static void postprocess_coefficients_concatenated(uint8_t *compressed_data, int coeff_count,
int16_t *output_y, int16_t *output_co, int16_t *output_cg) {
int map_bytes = (coeff_count + 7) / 8;
// Pointers to each section
uint8_t *y_map = compressed_data;
uint8_t *co_map = compressed_data + map_bytes;
uint8_t *cg_map = compressed_data + map_bytes * 2;
// Count non-zeros for each channel to find value arrays
int y_nonzeros = 0, co_nonzeros = 0, cg_nonzeros = 0;
for (int i = 0; i < coeff_count; i++) {
int byte_idx = i / 8;
int bit_idx = i % 8;
if (y_map[byte_idx] & (1 << bit_idx)) y_nonzeros++;
if (co_map[byte_idx] & (1 << bit_idx)) co_nonzeros++;
if (cg_map[byte_idx] & (1 << bit_idx)) cg_nonzeros++;
}
// Pointers to value arrays
int16_t *y_values = (int16_t *)(compressed_data + map_bytes * 3);
int16_t *co_values = y_values + y_nonzeros;
int16_t *cg_values = co_values + co_nonzeros;
// Clear outputs
memset(output_y, 0, coeff_count * sizeof(int16_t));
memset(output_co, 0, coeff_count * sizeof(int16_t));
memset(output_cg, 0, coeff_count * sizeof(int16_t));
// Reconstruct coefficients for each channel
int y_idx = 0, co_idx = 0, cg_idx = 0;
for (int i = 0; i < coeff_count; i++) {
int byte_idx = i / 8;
int bit_idx = i % 8;
if (y_map[byte_idx] & (1 << bit_idx)) {
output_y[i] = y_values[y_idx++];
}
if (co_map[byte_idx] & (1 << bit_idx)) {
output_co[i] = co_values[co_idx++];
}
if (cg_map[byte_idx] & (1 << bit_idx)) {
output_cg[i] = cg_values[cg_idx++];
}
}
}
// TAV header structure (32 bytes)
typedef struct {
uint8_t magic[8];
@@ -588,37 +639,25 @@ static int decode_frame(tav_decoder_t *decoder) {
int16_t *quantized_co = malloc(coeff_count * sizeof(int16_t));
int16_t *quantized_cg = malloc(coeff_count * sizeof(int16_t));
// Postprocess coefficients from significance map format
// First find where each channel's data starts by reading the preprocessing output
size_t y_map_bytes = (coeff_count + 7) / 8;
// Use concatenated maps format: [Y_map][Co_map][Cg_map][Y_vals][Co_vals][Cg_vals]
postprocess_coefficients_concatenated(coeff_ptr, coeff_count, quantized_y, quantized_co, quantized_cg);
// Count non-zeros in Y significance map to find Y data size
int y_nonzeros = 0;
for (int i = 0; i < y_map_bytes; i++) {
uint8_t byte = coeff_ptr[i];
for (int bit = 0; bit < 8 && i*8+bit < coeff_count; bit++) {
if (byte & (1 << bit)) y_nonzeros++;
}
// Calculate total processed data size for concatenated format
int map_bytes = (coeff_count + 7) / 8;
int y_nonzeros = 0, co_nonzeros = 0, cg_nonzeros = 0;
// Count non-zeros in each channel's significance map
for (int i = 0; i < coeff_count; i++) {
int byte_idx = i / 8;
int bit_idx = i % 8;
if (coeff_ptr[byte_idx] & (1 << bit_idx)) y_nonzeros++; // Y map
if (coeff_ptr[map_bytes + byte_idx] & (1 << bit_idx)) co_nonzeros++; // Co map
if (coeff_ptr[map_bytes * 2 + byte_idx] & (1 << bit_idx)) cg_nonzeros++; // Cg map
}
size_t y_data_size = y_map_bytes + y_nonzeros * sizeof(int16_t);
// Count non-zeros in Co significance map
uint8_t *co_ptr = coeff_ptr + y_data_size;
int co_nonzeros = 0;
for (int i = 0; i < y_map_bytes; i++) {
uint8_t byte = co_ptr[i];
for (int bit = 0; bit < 8 && i*8+bit < coeff_count; bit++) {
if (byte & (1 << bit)) co_nonzeros++;
}
}
size_t co_data_size = y_map_bytes + co_nonzeros * sizeof(int16_t);
uint8_t *cg_ptr = co_ptr + co_data_size;
// Decompress each channel
postprocess_coefficients(coeff_ptr, coeff_count, quantized_y);
postprocess_coefficients(co_ptr, coeff_count, quantized_co);
postprocess_coefficients(cg_ptr, coeff_count, quantized_cg);
// Total size consumed: 3 maps + all non-zero values
size_t total_processed_size = map_bytes * 3 + (y_nonzeros + co_nonzeros + cg_nonzeros) * sizeof(int16_t);
// Apply dequantization (perceptual for version 5, uniform for earlier versions)
const int is_perceptual = (decoder->header.version == 5);