[FFmpeg-cvslog] r14860 - in trunk/libavcodec: ac3dec.c ac3enc.c
jbr
subversion
Wed Aug 20 02:32:17 CEST 2008
Author: jbr
Date: Wed Aug 20 02:32:17 2008
New Revision: 14860
Log:
commit the OKed parts of the E-AC-3 decoder
Modified:
trunk/libavcodec/ac3dec.c
trunk/libavcodec/ac3enc.c
Modified: trunk/libavcodec/ac3dec.c
==============================================================================
--- trunk/libavcodec/ac3dec.c (original)
+++ trunk/libavcodec/ac3dec.c Wed Aug 20 02:32:17 2008
@@ -1,8 +1,10 @@
/*
* AC-3 Audio Decoder
- * This code is developed as part of Google Summer of Code 2006 Program.
+ * This code was developed as part of Google Summer of Code 2006.
+ * E-AC-3 support was added as part of Google Summer of Code 2007.
*
* Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com).
+ * Copyright (c) 2007-2008 Bartlomiej Wolowiec <bartek.wolowiec at gmail.com>
* Copyright (c) 2007 Justin Ruggles <justin.ruggles at gmail.com>
*
* Portions of this code are derived from liba52
@@ -302,10 +304,23 @@ static int parse_frame_header(AC3DecodeC
s->channel_in_cpl[s->lfe_ch] = 0;
}
- if(hdr.bitstream_id > 10)
- return AC3_PARSE_ERROR_BSID;
-
+ if (hdr.bitstream_id <= 10) {
+ s->eac3 = 0;
+ s->snr_offset_strategy = 2;
+ s->block_switch_syntax = 1;
+ s->dither_flag_syntax = 1;
+ s->bit_allocation_syntax = 1;
+ s->fast_gain_syntax = 0;
+ s->first_cpl_leak = 0;
+ s->dba_syntax = 1;
+ s->skip_syntax = 1;
+ 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;
+ }
}
/**
@@ -533,6 +548,25 @@ static void remove_dithering(AC3DecodeCo
}
}
+#if 0
+static void get_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);
+ } 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);
+ 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.
*/
@@ -698,19 +732,23 @@ static int decode_audio_block(AC3DecodeC
/* block switch flags */
different_transforms = 0;
+ if (s->block_switch_syntax) {
for (ch = 1; ch <= fbw_channels; ch++) {
s->block_switch[ch] = get_bits1(gbc);
if(ch > 1 && s->block_switch[ch] != s->block_switch[1])
different_transforms = 1;
}
+ }
/* 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;
}
+ }
/* dynamic range */
i = !(s->channel_mode);
@@ -870,6 +908,7 @@ static int decode_audio_block(AC3DecodeC
}
/* bit allocation information */
+ if (s->bit_allocation_syntax) {
if (get_bits1(gbc)) {
s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
@@ -882,6 +921,7 @@ static int decode_audio_block(AC3DecodeC
av_log(s->avctx, AV_LOG_ERROR, "new bit allocation info must be present in block 0\n");
return -1;
}
+ }
/* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
if (get_bits1(gbc)) {
@@ -910,7 +950,7 @@ static int decode_audio_block(AC3DecodeC
}
/* delta bit allocation information */
- if (get_bits1(gbc)) {
+ if (s->dba_syntax && get_bits1(gbc)) {
/* delta bit allocation exists (strategy) */
for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
s->dba_mode[ch] = get_bits(gbc, 2);
@@ -959,16 +999,18 @@ static int decode_audio_block(AC3DecodeC
}
if(bit_alloc_stages[ch] > 0) {
/* Compute bit allocation */
+ const uint8_t *bap_tab = s->channel_uses_aht[ch] ?
+ ff_eac3_hebap_tab : ff_ac3_bap_tab;
ff_ac3_bit_alloc_calc_bap(s->mask[ch], s->psd[ch],
s->start_freq[ch], s->end_freq[ch],
s->snr_offset[ch],
s->bit_alloc_params.floor,
- ff_ac3_bap_tab, s->bap[ch]);
+ bap_tab, s->bap[ch]);
}
}
/* unused dummy data */
- if (get_bits1(gbc)) {
+ if (s->skip_syntax && get_bits1(gbc)) {
int skipl = get_bits(gbc, 9);
while(skipl--)
skip_bits(gbc, 8);
@@ -978,6 +1020,10 @@ static int decode_audio_block(AC3DecodeC
this also uncouples channels if coupling is in use. */
get_transform_coeffs(s);
+ /* TODO: generate enhanced coupling coordinates and uncouple */
+
+ /* TODO: apply spectral extension */
+
/* recover coefficients if rematrixing is in use */
if(s->channel_mode == AC3_CHMODE_STEREO)
do_rematrixing(s);
@@ -1161,5 +1207,5 @@ AVCodec ac3_decoder = {
.init = ac3_decode_init,
.close = ac3_decode_end,
.decode = ac3_decode_frame,
- .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52 / AC-3"),
+ .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52 (AC-3, E-AC-3)"),
};
Modified: trunk/libavcodec/ac3enc.c
==============================================================================
--- trunk/libavcodec/ac3enc.c (original)
+++ trunk/libavcodec/ac3enc.c Wed Aug 20 02:32:17 2008
@@ -1365,5 +1365,5 @@ AVCodec ac3_encoder = {
AC3_encode_close,
NULL,
.sample_fmts = (enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
- .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52 / AC-3"),
+ .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52 (AC-3, E-AC-3)"),
};
More information about the ffmpeg-cvslog
mailing list