s->downmixed = 1;
/* allocate context input buffer */
- if (avctx->error_resilience >= FF_ER_CAREFUL) {
+ if (avctx->error_recognition >= FF_ER_CAREFUL) {
s->input_buffer = av_mallocz(AC3_FRAME_BUFFER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
if (!s->input_buffer)
return AVERROR_NOMEM;
memset(s->channel_uses_aht, 0, sizeof(s->channel_uses_aht));
return ac3_parse_header(s);
} else {
- /*s->eac3 = 1;
- return ff_eac3_parse_header(s);*/
- return AC3_PARSE_ERROR_BSID;
+ s->eac3 = 1;
+ return ff_eac3_parse_header(s);
}
}
} mant_groups;
/**
- * Get the transform coefficients for a particular channel
+ * Decode the transform coefficients for a particular channel
* reference: Section 7.3 Quantization and Decoding of Mantissas
*/
-static void get_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m)
+static void ac3_decode_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m)
{
GetBitContext *gbc = &s->gbc;
int i, gcode, tbap, start, end;
}
}
-#if 0
-static void get_transform_coeffs_ch(AC3DecodeContext *s, int blk, int ch,
+static void decode_transform_coeffs_ch(AC3DecodeContext *s, int blk, int ch,
mant_groups *m)
{
if (!s->channel_uses_aht[ch]) {
- ac3_get_transform_coeffs_ch(s, ch, m);
+ ac3_decode_transform_coeffs_ch(s, ch, m);
} else {
/* if AHT is used, mantissas for all blocks are encoded in the first
block of the frame. */
int bin;
if (!blk)
- ff_eac3_get_transform_coeffs_aht_ch(s, ch);
+ ff_eac3_decode_transform_coeffs_aht_ch(s, ch);
for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) {
s->fixed_coeffs[ch][bin] = s->pre_mantissa[ch][bin][blk] >> s->dexps[ch][bin];
}
}
}
-#endif
/**
- * Get the transform coefficients.
+ * Decode the transform coefficients.
*/
-static void get_transform_coeffs(AC3DecodeContext *s)
+static void decode_transform_coeffs(AC3DecodeContext *s, int blk)
{
int ch, end;
int got_cplchan = 0;
for (ch = 1; ch <= s->channels; ch++) {
/* transform coefficients for full-bandwidth channel */
- get_transform_coeffs_ch(s, ch, &m);
+ decode_transform_coeffs_ch(s, blk, ch, &m);
/* tranform coefficients for coupling channel come right after the
coefficients for the first coupled channel*/
if (s->channel_in_cpl[ch]) {
if (!got_cplchan) {
- get_transform_coeffs_ch(s, CPL_CH, &m);
+ decode_transform_coeffs_ch(s, blk, CPL_CH, &m);
calc_transform_coeffs_cpl(s);
got_cplchan = 1;
}
while(++end < 256);
}
- /* if any channel doesn't use dithering, zero appropriate coefficients */
- if(!s->dither_all)
- remove_dithering(s);
+ /* zero the dithered coefficients for appropriate channels */
+ remove_dithering(s);
}
/**
}
}
+/**
+ * Decode band structure for coupling, spectral extension, or enhanced coupling.
+ * @param[in] gbc bit reader context
+ * @param[in] blk block number
+ * @param[in] eac3 flag to indicate E-AC-3
+ * @param[in] ecpl flag to indicate enhanced coupling
+ * @param[in] start_subband subband number for start of range
+ * @param[in] end_subband subband number for end of range
+ * @param[in] default_band_struct default band structure table
+ * @param[out] band_struct decoded band structure
+ * @param[out] num_subbands number of subbands (optionally NULL)
+ * @param[out] num_bands number of bands (optionally NULL)
+ * @param[out] band_sizes array containing the number of bins in each band (optionally NULL)
+ */
+static void decode_band_structure(GetBitContext *gbc, int blk, int eac3,
+ int ecpl, int start_subband, int end_subband,
+ const uint8_t *default_band_struct,
+ uint8_t *band_struct, int *num_subbands,
+ int *num_bands, uint8_t *band_sizes)
+{
+ int subbnd, bnd, n_subbands, n_bands=0;
+ uint8_t bnd_sz[22];
+
+ n_subbands = end_subband - start_subband;
+
+ /* decode band structure from bitstream or use default */
+ if (!eac3 || get_bits1(gbc)) {
+ for (subbnd = 0; subbnd < n_subbands - 1; subbnd++) {
+ band_struct[subbnd] = get_bits1(gbc);
+ }
+ } else if (!blk) {
+ memcpy(band_struct,
+ &default_band_struct[start_subband+1],
+ n_subbands-1);
+ }
+ band_struct[n_subbands-1] = 0;
+
+ /* calculate number of bands and band sizes based on band structure.
+ note that the first 4 subbands in enhanced coupling span only 6 bins
+ instead of 12. */
+ if (num_bands || band_sizes ) {
+ n_bands = n_subbands;
+ bnd_sz[0] = ecpl ? 6 : 12;
+ for (bnd = 0, subbnd = 1; subbnd < n_subbands; subbnd++) {
+ int subbnd_size = (ecpl && subbnd < 4) ? 6 : 12;
+ if (band_struct[subbnd-1]) {
+ n_bands--;
+ bnd_sz[bnd] += subbnd_size;
+ } else {
+ bnd_sz[++bnd] = subbnd_size;
+ }
+ }
+ }
+
+ /* set optional output params */
+ if (num_subbands)
+ *num_subbands = n_subbands;
+ if (num_bands)
+ *num_bands = n_bands;
+ if (band_sizes)
+ memcpy(band_sizes, bnd_sz, n_bands);
+}
+
/**
* Decode a single audio block from the AC-3 bitstream.
*/
/* dithering flags */
if (s->dither_flag_syntax) {
- s->dither_all = 1;
for (ch = 1; ch <= fbw_channels; ch++) {
s->dither_flag[ch] = get_bits1(gbc);
- if(!s->dither_flag[ch])
- s->dither_all = 0;
}
}
/* TODO: spectral extension coordinates */
/* coupling strategy */
- if (get_bits1(gbc)) {
+ if (s->eac3 ? s->cpl_strategy_exists[blk] : get_bits1(gbc)) {
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
if (!s->eac3)
- s->cpl_in_use[blk] = get_bits1(gbc);
+ s->cpl_in_use[blk] = get_bits1(gbc);
if (s->cpl_in_use[blk]) {
/* coupling in use */
- int cpl_begin_freq, cpl_end_freq;
+ int cpl_start_subband, cpl_end_subband;
if (channel_mode < AC3_CHMODE_STEREO) {
av_log(s->avctx, AV_LOG_ERROR, "coupling not allowed in mono or dual-mono\n");
s->channel_in_cpl[1] = 1;
s->channel_in_cpl[2] = 1;
} else {
- for (ch = 1; ch <= fbw_channels; ch++)
- s->channel_in_cpl[ch] = get_bits1(gbc);
+ for (ch = 1; ch <= fbw_channels; ch++)
+ s->channel_in_cpl[ch] = get_bits1(gbc);
}
/* phase flags in use */
/* coupling frequency range */
/* TODO: modify coupling end freq if spectral extension is used */
- cpl_begin_freq = get_bits(gbc, 4);
- cpl_end_freq = get_bits(gbc, 4);
- if (3 + cpl_end_freq - cpl_begin_freq < 0) {
- av_log(s->avctx, AV_LOG_ERROR, "3+cplendf = %d < cplbegf = %d\n", 3+cpl_end_freq, cpl_begin_freq);
+ cpl_start_subband = get_bits(gbc, 4);
+ cpl_end_subband = get_bits(gbc, 4) + 3;
+ s->num_cpl_subbands = cpl_end_subband - cpl_start_subband;
+ if (s->num_cpl_subbands < 0) {
+ av_log(s->avctx, AV_LOG_ERROR, "invalid coupling range (%d > %d)\n",
+ cpl_start_subband, cpl_end_subband);
return -1;
}
- s->num_cpl_bands = s->num_cpl_subbands = 3 + cpl_end_freq - cpl_begin_freq;
- s->start_freq[CPL_CH] = cpl_begin_freq * 12 + 37;
- s->end_freq[CPL_CH] = cpl_end_freq * 12 + 73;
-
- /* coupling band structure */
- if (!s->eac3 || get_bits1(gbc)) {
- for (bnd = 0; bnd < s->num_cpl_subbands - 1; bnd++) {
- s->cpl_band_struct[bnd] = get_bits1(gbc);
- }
- } else if (!blk) {
- }
- s->cpl_band_struct[s->num_cpl_subbands-1] = 0;
-
- /* calculate number of coupling bands based on band structure */
- for (bnd = 0; bnd < s->num_cpl_subbands-1; bnd++) {
- s->num_cpl_bands -= s->cpl_band_struct[bnd];
- }
+ s->start_freq[CPL_CH] = cpl_start_subband * 12 + 37;
+ s->end_freq[CPL_CH] = cpl_end_subband * 12 + 37;
+
+ decode_band_structure(gbc, blk, s->eac3, 0,
+ cpl_start_subband, cpl_end_subband,
+ ff_eac3_default_cpl_band_struct,
+ s->cpl_band_struct, &s->num_cpl_subbands,
+ &s->num_cpl_bands, NULL);
} else {
/* coupling not in use */
for (ch = 1; ch <= fbw_channels; ch++) {
s->channel_in_cpl[ch] = 0;
s->first_cpl_coords[ch] = 1;
}
- s->first_cpl_leak = 1;
+ s->first_cpl_leak = s->eac3;
s->phase_flags_in_use = 0;
}
} else if (!s->eac3) {
if(!blk) {
- av_log(s->avctx, AV_LOG_ERROR, "new coupling strategy must be present in block 0\n");
- return -1;
- } else {
- s->cpl_in_use[blk] = s->cpl_in_use[blk-1];
- }
+ av_log(s->avctx, AV_LOG_ERROR, "new coupling strategy must be present in block 0\n");
+ return -1;
+ } else {
+ s->cpl_in_use[blk] = s->cpl_in_use[blk-1];
+ }
}
cpl_in_use = s->cpl_in_use[blk];
for (ch = 1; ch <= fbw_channels; ch++) {
if (s->channel_in_cpl[ch]) {
- if (get_bits1(gbc)) {
+ if ((s->eac3 && s->first_cpl_coords[ch]) || get_bits1(gbc)) {
int master_cpl_coord, cpl_coord_exp, cpl_coord_mant;
+ s->first_cpl_coords[ch] = 0;
cpl_coords_exist = 1;
master_cpl_coord = 3 * get_bits(gbc, 2);
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
av_log(s->avctx, AV_LOG_ERROR, "new coupling coordinates must be present in block 0\n");
return -1;
}
+ } else {
+ /* channel not in coupling */
+ s->first_cpl_coords[ch] = 1;
}
}
/* phase flags */
}
/* exponent strategies for each channel */
- s->exp_strategy[blk][CPL_CH] = EXP_REUSE;
- s->exp_strategy[blk][s->lfe_ch] = EXP_REUSE;
for (ch = !cpl_in_use; ch <= s->channels; ch++) {
- s->exp_strategy[blk][ch] = get_bits(gbc, 2 - (ch == s->lfe_ch));
+ if (!s->eac3)
+ s->exp_strategy[blk][ch] = get_bits(gbc, 2 - (ch == s->lfe_ch));
if(s->exp_strategy[blk][ch] != EXP_REUSE)
bit_alloc_stages[ch] = 3;
}
else {
int bandwidth_code = get_bits(gbc, 6);
if (bandwidth_code > 60) {
- av_log(s->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60", bandwidth_code);
+ av_log(s->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60\n", bandwidth_code);
return -1;
}
s->end_freq[ch] = bandwidth_code * 3 + 73;
}
/* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
- if (get_bits1(gbc)) {
- int csnr;
- csnr = (get_bits(gbc, 6) - 15) << 4;
- for (ch = !cpl_in_use; ch <= s->channels; ch++) { /* snr offset and fast gain */
- s->snr_offset[ch] = (csnr + get_bits(gbc, 4)) << 2;
- s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
+ if(!s->eac3 || !blk){
+ if(s->snr_offset_strategy && get_bits1(gbc)) {
+ int snr = 0;
+ int csnr;
+ csnr = (get_bits(gbc, 6) - 15) << 4;
+ for (i = ch = !cpl_in_use; ch <= s->channels; ch++) {
+ /* snr offset */
+ if (ch == i || s->snr_offset_strategy == 2)
+ snr = (csnr + get_bits(gbc, 4)) << 2;
+ /* run at least last bit allocation stage if snr offset changes */
+ if(blk && s->snr_offset[ch] != snr) {
+ bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 1);
+ }
+ s->snr_offset[ch] = snr;
+
+ /* fast gain (normal AC-3 only) */
+ if (!s->eac3) {
+ int prev = s->fast_gain[ch];
+ s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
+ /* run last 2 bit allocation stages if fast gain changes */
+ if(blk && prev != s->fast_gain[ch])
+ bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
+ }
+ }
+ } else if (!s->eac3 && !blk) {
+ av_log(s->avctx, AV_LOG_ERROR, "new snr offsets must be present in block 0\n");
+ return -1;
}
- memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
- } else if (!blk) {
- av_log(s->avctx, AV_LOG_ERROR, "new snr offsets must be present in block 0\n");
- return -1;
}
/* fast gain (E-AC-3 only) */
/* coupling leak information */
if (cpl_in_use) {
- if (get_bits1(gbc)) {
- s->bit_alloc_params.cpl_fast_leak = get_bits(gbc, 3);
- s->bit_alloc_params.cpl_slow_leak = get_bits(gbc, 3);
- bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
- } else if (!blk) {
+ if (s->first_cpl_leak || get_bits1(gbc)) {
+ int fl = get_bits(gbc, 3);
+ int sl = get_bits(gbc, 3);
+ /* run last 2 bit allocation stages for coupling channel if
+ coupling leak changes */
+ if(blk && (fl != s->bit_alloc_params.cpl_fast_leak ||
+ sl != s->bit_alloc_params.cpl_slow_leak)) {
+ bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
+ }
+ s->bit_alloc_params.cpl_fast_leak = fl;
+ s->bit_alloc_params.cpl_slow_leak = sl;
+ } else if (!s->eac3 && !blk) {
av_log(s->avctx, AV_LOG_ERROR, "new coupling leak info must be present in block 0\n");
return -1;
}
+ s->first_cpl_leak = 0;
}
/* delta bit allocation information */
/* unpack the transform coefficients
this also uncouples channels if coupling is in use. */
- get_transform_coeffs(s);
+ decode_transform_coeffs(s, blk);
/* TODO: generate enhanced coupling coordinates and uncouple */
}
/* check for crc mismatch */
- if(err != AC3_PARSE_ERROR_FRAME_SIZE && avctx->error_resilience >= FF_ER_CAREFUL) {
+ if(err != AC3_PARSE_ERROR_FRAME_SIZE && avctx->error_recognition >= FF_ER_CAREFUL) {
if(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2], s->frame_size-2)) {
av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n");
err = AC3_PARSE_ERROR_CRC;
const float *output[s->out_channels];
if (!err && decode_audio_block(s, blk)) {
av_log(avctx, AV_LOG_ERROR, "error decoding the audio block\n");
+ err = 1;
}
for (ch = 0; ch < s->out_channels; ch++)
output[ch] = s->output[ch];
.init = ac3_decode_init,
.close = ac3_decode_end,
.decode = ac3_decode_frame,
- .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52 (AC-3, E-AC-3)"),
+ .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
+};
+
+AVCodec eac3_decoder = {
+ .name = "eac3",
+ .type = CODEC_TYPE_AUDIO,
+ .id = CODEC_ID_EAC3,
+ .priv_data_size = sizeof (AC3DecodeContext),
+ .init = ac3_decode_init,
+ .close = ac3_decode_end,
+ .decode = ac3_decode_frame,
+ .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52B (AC-3, E-AC-3)"),
};
projects / ffmpeg / blobdiff