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Add channel layout support to the AC-3 encoder. 

Originally committed as revision 18623 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2009-04-19 15:06:13 +00:00
parent bfeca7beb6
commit 120b4557f3
1 changed files with 68 additions and 17 deletions
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85
libavcodec/ac3enc.c
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@ -30,6 +30,7 @@
#include "get_bits.h" // for ff_reverse
#include "put_bits.h"
#include "ac3.h"
#include "audioconvert.h"
typedef struct AC3EncodeContext {
PutBitContext pb;
@ -609,37 +610,67 @@ static int compute_bit_allocation(AC3EncodeContext *s,
return 0;
}
static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
int64_t *channel_layout)
{
int ch_layout;
if (channels < 1 || channels > AC3_MAX_CHANNELS)
return -1;
if ((uint64_t)*channel_layout > 0x7FF)
return -1;
ch_layout = *channel_layout;
if (!ch_layout)
ch_layout = avcodec_guess_channel_layout(channels, CODEC_ID_AC3, NULL);
if (avcodec_channel_layout_num_channels(ch_layout) != channels)
return -1;
s->lfe = !!(ch_layout & CH_LOW_FREQUENCY);
s->nb_all_channels = channels;
s->nb_channels = channels - s->lfe;
s->lfe_channel = s->lfe ? s->nb_channels : -1;
if (s->lfe)
ch_layout -= CH_LOW_FREQUENCY;
switch (ch_layout) {
case CH_LAYOUT_MONO: s->channel_mode = AC3_CHMODE_MONO; break;
case CH_LAYOUT_STEREO: s->channel_mode = AC3_CHMODE_STEREO; break;
case CH_LAYOUT_SURROUND: s->channel_mode = AC3_CHMODE_3F; break;
case CH_LAYOUT_2_1: s->channel_mode = AC3_CHMODE_2F1R; break;
case CH_LAYOUT_4POINT0: s->channel_mode = AC3_CHMODE_3F1R; break;
case CH_LAYOUT_QUAD:
case CH_LAYOUT_2_2: s->channel_mode = AC3_CHMODE_2F2R; break;
case CH_LAYOUT_5POINT0:
case CH_LAYOUT_5POINT0_BACK: s->channel_mode = AC3_CHMODE_3F2R; break;
default:
return -1;
}
s->channel_map = ff_ac3_enc_channel_map[s->channel_mode][s->lfe];
*channel_layout = ch_layout;
if (s->lfe)
*channel_layout |= CH_LOW_FREQUENCY;
return 0;
}
static av_cold int AC3_encode_init(AVCodecContext *avctx)
{
int freq = avctx->sample_rate;
int bitrate = avctx->bit_rate;
int channels = avctx->channels;
AC3EncodeContext *s = avctx->priv_data;
int i, j, ch;
float alpha;
int bw_code;
static const uint8_t channel_mode_defs[6] = {
0x01, /* C */
0x02, /* L R */
0x03, /* L C R */
0x06, /* L R SL SR */
0x07, /* L C R SL SR */
0x07, /* L C R SL SR (+LFE) */
};
avctx->frame_size = AC3_FRAME_SIZE;
ac3_common_init();
/* number of channels */
if (channels < 1 || channels > 6)
if (set_channel_info(s, avctx->channels, &avctx->channel_layout)) {
av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n");
return -1;
s->channel_mode = channel_mode_defs[channels - 1];
s->lfe = (channels == 6) ? 1 : 0;
s->nb_all_channels = channels;
s->nb_channels = channels > 5 ? 5 : channels;
s->lfe_channel = s->lfe ? 5 : -1;
s->channel_map = ff_ac3_enc_channel_map[s->channel_mode][s->lfe];
}
/* frequency */
for(i=0;i<3;i++) {
@ -1368,4 +1399,24 @@ AVCodec ac3_encoder = {
NULL,
.sample_fmts = (enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
.long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
.channel_layouts = (int64_t[]){
CH_LAYOUT_MONO,
CH_LAYOUT_STEREO,
CH_LAYOUT_2_1,
CH_LAYOUT_SURROUND,
CH_LAYOUT_2_2,
CH_LAYOUT_QUAD,
CH_LAYOUT_4POINT0,
CH_LAYOUT_5POINT0,
CH_LAYOUT_5POINT0_BACK,
(CH_LAYOUT_MONO | CH_LOW_FREQUENCY),
(CH_LAYOUT_STEREO | CH_LOW_FREQUENCY),
(CH_LAYOUT_2_1 | CH_LOW_FREQUENCY),
(CH_LAYOUT_SURROUND | CH_LOW_FREQUENCY),
(CH_LAYOUT_2_2 | CH_LOW_FREQUENCY),
(CH_LAYOUT_QUAD | CH_LOW_FREQUENCY),
(CH_LAYOUT_4POINT0 | CH_LOW_FREQUENCY),
CH_LAYOUT_5POINT1,
CH_LAYOUT_5POINT1_BACK,
0 },
};