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aacenc: add support for encoding 7.1 channel audio

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This commit implements support for 7.1 channel audio. There's no
more predefined bitstream channel mappings so going beyond 8 channels
(and 7 channels exactly) will require programmable channel elements,
which is already underway.
This commit is contained in:
Rostislav Pehlivanov 2015-10-12 15:53:17 +01:00
parent e679a1e65f
commit b3deaece87
2 changed files with 15 additions and 10 deletions
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5
libavcodec/aacenc.c
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@ -54,11 +54,12 @@ static void put_audio_specific_config(AVCodecContext *avctx)
{
PutBitContext pb;
AACEncContext *s = avctx->priv_data;
int channels = s->channels - (s->channels == 8 ? 1 : 0);
init_put_bits(&pb, avctx->extradata, avctx->extradata_size);
put_bits(&pb, 5, s->profile+1); //profile
put_bits(&pb, 4, s->samplerate_index); //sample rate index
put_bits(&pb, 4, s->channels);
put_bits(&pb, 4, channels);
//GASpecificConfig
put_bits(&pb, 1, 0); //frame length - 1024 samples
put_bits(&pb, 1, 0); //does not depend on core coder
@ -866,7 +867,7 @@ static av_cold int aac_encode_init(AVCodecContext *avctx)
ERROR_IF(i == 16 || i >= ff_aac_swb_size_1024_len || i >= ff_aac_swb_size_128_len,
"Unsupported sample rate %d\n", avctx->sample_rate);
ERROR_IF(s->channels > AAC_MAX_CHANNELS,
ERROR_IF(s->channels > AAC_MAX_CHANNELS || s->channels == 7,
"Unsupported number of channels: %d\n", s->channels);
WARN_IF(1024.0 * avctx->bit_rate / avctx->sample_rate > 6144 * s->channels,
"Too many bits per frame requested, clamping to max\n");

20
libavcodec/aacenctab.h
View File

@ -36,7 +36,7 @@
/** Total number of codebooks, including special ones **/
#define CB_TOT_ALL 15
#define AAC_MAX_CHANNELS 6
#define AAC_MAX_CHANNELS 8
extern const uint8_t *ff_aac_swb_size_1024[];
extern const int ff_aac_swb_size_1024_len;
@ -44,13 +44,15 @@ extern const uint8_t *ff_aac_swb_size_128[];
extern const int ff_aac_swb_size_128_len;
/** default channel configurations */
static const uint8_t aac_chan_configs[6][5] = {
{1, TYPE_SCE}, // 1 channel - single channel element
{1, TYPE_CPE}, // 2 channels - channel pair
{2, TYPE_SCE, TYPE_CPE}, // 3 channels - center + stereo
{3, TYPE_SCE, TYPE_CPE, TYPE_SCE}, // 4 channels - front center + stereo + back center
{3, TYPE_SCE, TYPE_CPE, TYPE_CPE}, // 5 channels - front center + stereo + back stereo
{4, TYPE_SCE, TYPE_CPE, TYPE_CPE, TYPE_LFE}, // 6 channels - front center + stereo + back stereo + LFE
static const uint8_t aac_chan_configs[AAC_MAX_CHANNELS][6] = {
{1, TYPE_SCE}, // 1 channel - single channel element
{1, TYPE_CPE}, // 2 channels - channel pair
{2, TYPE_SCE, TYPE_CPE}, // 3 channels - center + stereo
{3, TYPE_SCE, TYPE_CPE, TYPE_SCE}, // 4 channels - front center + stereo + back center
{3, TYPE_SCE, TYPE_CPE, TYPE_CPE}, // 5 channels - front center + stereo + back stereo
{4, TYPE_SCE, TYPE_CPE, TYPE_CPE, TYPE_LFE}, // 6 channels - front center + stereo + back stereo + LFE
{0}, // 7 channels - invalid without PCE
{5, TYPE_SCE, TYPE_CPE, TYPE_CPE, TYPE_CPE, TYPE_LFE}, // 8 channels - front center + front stereo + side stereo + back stereo + LFE
};
/**
@ -63,6 +65,8 @@ static const uint8_t aac_chan_maps[AAC_MAX_CHANNELS][AAC_MAX_CHANNELS] = {
{ 2, 0, 1, 3 },
{ 2, 0, 1, 3, 4 },
{ 2, 0, 1, 4, 5, 3 },
{ 0 },
{ 2, 0, 1, 6, 7, 4, 5, 3 },
};
/* duplicated from avpriv_mpeg4audio_sample_rates to avoid shared build