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commit more OKed parts of the E-AC-3 decoder 

Originally committed as revision 15087 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2008-08-31 02:30:09 +00:00
parent 064abb8aea
commit 8dfc56ec32
1 changed files with 35 additions and 10 deletions
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45
libavcodec/ac3dec.c
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@ -964,17 +964,34 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
}
/* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
if (get_bits1(gbc)) {
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 (ch = !cpl_in_use; ch <= s->channels; ch++) { /* snr offset and fast gain */
s->snr_offset[ch] = (csnr + get_bits(gbc, 4)) << 2;
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)];
}
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
} else if (!blk) {
/* 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;
}
}
/* fast gain (E-AC-3 only) */
@ -998,14 +1015,22 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
/* 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);
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);
} else if (!blk) {
}
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 */