aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec
diff options
context:
space:
mode:
authorJustin Ruggles <justin.ruggles@gmail.com>2008-08-23 01:51:42 +0000
committerJustin Ruggles <justin.ruggles@gmail.com>2008-08-23 01:51:42 +0000
commit6fafb0202ad8b2e8aa9affcf6749ee721cef1a0c (patch)
tree0a858d26327d0ab932288c6d5cb7294252fe0e00 /libavcodec
parent26efefc52c8d16913a17eb518983da9d26888f24 (diff)
downloadffmpeg-6fafb0202ad8b2e8aa9affcf6749ee721cef1a0c.tar.gz
add some approved parts of the E-AC-3 decoder
Originally committed as revision 14910 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec')
-rw-r--r--libavcodec/ac3dec.c71
1 files changed, 64 insertions, 7 deletions
diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c
index 0d2c4a62f6..c55ce9e39f 100644
--- a/libavcodec/ac3dec.c
+++ b/libavcodec/ac3dec.c
@@ -761,9 +761,21 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
}
} while(i--);
+ /* spectral extension strategy */
+ if (s->eac3 && (!blk || get_bits1(gbc))) {
+ if (get_bits1(gbc)) {
+ av_log_missing_feature(s->avctx, "Spectral extension", 1);
+ return -1;
+ }
+ /* TODO: parse spectral extension strategy info */
+ }
+
+ /* TODO: spectral extension coordinates */
+
/* coupling strategy */
if (get_bits1(gbc)) {
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
+ if (!s->eac3)
s->cpl_in_use[blk] = get_bits1(gbc);
if (s->cpl_in_use[blk]) {
/* coupling in use */
@@ -774,15 +786,28 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
return -1;
}
+ /* check for enhanced coupling */
+ if (s->eac3 && get_bits1(gbc)) {
+ /* TODO: parse enhanced coupling strategy info */
+ av_log_missing_feature(s->avctx, "Enhanced coupling", 1);
+ return -1;
+ }
+
/* determine which channels are coupled */
+ if (s->eac3 && s->channel_mode == AC3_CHMODE_STEREO) {
+ 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);
+ }
/* phase flags in use */
if (channel_mode == AC3_CHMODE_STEREO)
s->phase_flags_in_use = get_bits1(gbc);
- /* coupling frequency range and band structure */
+ /* 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) {
@@ -792,24 +817,37 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
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++) {
- if (get_bits1(gbc)) {
- s->cpl_band_struct[bnd] = 1;
- s->num_cpl_bands--;
+ 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];
+ }
} else {
/* coupling not in use */
- for (ch = 1; ch <= fbw_channels; ch++)
+ 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->phase_flags_in_use = 0;
}
- } else if (!blk) {
+ } 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];
}
+ }
cpl_in_use = s->cpl_in_use[blk];
/* coupling coordinates */
@@ -847,7 +885,7 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
/* stereo rematrixing strategy and band structure */
if (channel_mode == AC3_CHMODE_STEREO) {
- if (get_bits1(gbc)) {
+ if ((s->eac3 && !blk) || get_bits1(gbc)) {
s->num_rematrixing_bands = 4;
if(cpl_in_use && s->start_freq[CPL_CH] <= 61)
s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37);
@@ -937,6 +975,25 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
return -1;
}
+ /* fast gain (E-AC-3 only) */
+ if (s->fast_gain_syntax && get_bits1(gbc)) {
+ for (ch = !cpl_in_use; ch <= s->channels; ch++) {
+ 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) {
+ for (ch = !cpl_in_use; ch <= s->channels; ch++)
+ s->fast_gain[ch] = ff_ac3_fast_gain_tab[4];
+ }
+
+ /* E-AC-3 to AC-3 converter SNR offset */
+ if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && get_bits1(gbc)) {
+ skip_bits(gbc, 10); // skip converter snr offset
+ }
+
/* coupling leak information */
if (cpl_in_use) {
if (get_bits1(gbc)) {