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Add static bitrate allocation and force CELT-only for ambisonics encoding

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Signed-off-by: Jean-Marc Valin <jmvalin@jmvalin.ca>
This commit is contained in:
Michael Graczyk 2016-04-04 19:31:04 -07:00 • committed by Jean-Marc Valin
parent 3925668bbb
commit 1ac3a5630a
1 changed files with 93 additions and 10 deletions
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103
src/opus_multistream_encoder.c
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@ -512,7 +512,8 @@ int opus_multistream_surround_encoder_init(
int application
)
{
int mapping_type;
MappingType mapping_type;
if ((channels>255) || (channels<1))
return OPUS_BAD_ARG;
st->lfe_stream = -1;
@ -657,24 +658,19 @@ OpusMSEncoder *opus_multistream_surround_encoder_create(
return st;
}
static opus_int32 surround_rate_allocation(
static void surround_rate_allocation(
OpusMSEncoder *st,
opus_int32 *rate,
int frame_size
int frame_size,
opus_int32 Fs
)
{
int i;
opus_int32 channel_rate;
opus_int32 Fs;
char *ptr;
int stream_offset;
int lfe_offset;
int coupled_ratio; /* Q8 */
int lfe_ratio; /* Q8 */
opus_int32 rate_sum=0;
ptr = (char*)st + align(sizeof(OpusMSEncoder));
opus_encoder_ctl((OpusEncoder*)ptr, OPUS_GET_SAMPLE_RATE(&Fs));
if (st->bitrate_bps > st->layout.nb_channels*40000)
stream_offset = 20000;
@ -727,6 +723,88 @@ static opus_int32 surround_rate_allocation(
rate[i] = stream_offset+channel_rate;
else
rate[i] = lfe_offset+(channel_rate*lfe_ratio>>8);
}
}
#ifdef ENABLE_EXPERIMENTAL_AMBISONICS
static void ambisonics_rate_allocation(
OpusMSEncoder *st,
opus_int32 *rate,
int frame_size,
opus_int32 Fs
)
{
int i;
int non_mono_rate;
int total_rate;
/* The mono channel gets (rate_ratio_num / rate_ratio_den) times as many bits
* as all other channels */
const int rate_ratio_num = 4;
const int rate_ratio_den = 3;
const int num_channels = st->layout.nb_streams;
if (st->bitrate_bps==OPUS_AUTO)
{
total_rate = num_channels * (20000 + st->layout.nb_streams*(Fs+60*Fs/frame_size));
} else if (st->bitrate_bps==OPUS_BITRATE_MAX)
{
total_rate = num_channels * 320000;
} else {
total_rate = st->bitrate_bps;
}
/* Let y be the non-mono rate and let p, q be integers such that the mono
* channel rate is (p/q) * y.
* Also let T be the total bitrate to allocate. Then
* (n - 1) y + (p/q) y = T
* y = (T q) / (qn - q + p)
*/
non_mono_rate =
total_rate * rate_ratio_den
/ (rate_ratio_den*num_channels + rate_ratio_num - rate_ratio_den);
#ifndef FIXED_POINT
if (st->variable_duration==OPUS_FRAMESIZE_VARIABLE && frame_size != Fs/50)
{
opus_int32 bonus = 60*(Fs/frame_size-50);
non_mono_rate += bonus;
}
#endif
rate[0] = total_rate - (num_channels - 1) * non_mono_rate;
for (i=1;i<st->layout.nb_streams;i++)
{
rate[i] = non_mono_rate;
}
}
#endif /* ENABLE_EXPERIMENTAL_AMBISONICS */
static opus_int32 rate_allocation(
OpusMSEncoder *st,
opus_int32 *rate,
int frame_size
)
{
int i;
opus_int32 rate_sum=0;
opus_int32 Fs;
char *ptr;
ptr = (char*)st + align(sizeof(OpusMSEncoder));
opus_encoder_ctl((OpusEncoder*)ptr, OPUS_GET_SAMPLE_RATE(&Fs));
#ifdef ENABLE_EXPERIMENTAL_AMBISONICS
if (st->mapping_type == MAPPING_TYPE_AMBISONICS) {
ambisonics_rate_allocation(st, rate, frame_size, Fs);
} else
#endif
{
surround_rate_allocation(st, rate, frame_size, Fs);
}
for (i=0;i<st->layout.nb_streams;i++)
{
rate[i] = IMAX(rate[i], 500);
rate_sum += rate[i];
}
@ -829,7 +907,7 @@ static int opus_multistream_encode_native
}
/* Compute bitrate allocation between streams (this could be a lot better) */
rate_sum = surround_rate_allocation(st, bitrates, frame_size);
rate_sum = rate_allocation(st, bitrates, frame_size);
if (!vbr)
{
@ -873,6 +951,11 @@ static int opus_multistream_encode_native
opus_encoder_ctl(enc, OPUS_SET_FORCE_CHANNELS(2));
}
}
#ifdef ENABLE_EXPERIMENTAL_AMBISONICS
else if (st->mapping_type == MAPPING_TYPE_AMBISONICS) {
opus_encoder_ctl(enc, OPUS_SET_FORCE_MODE(MODE_CELT_ONLY));
}
#endif
}
ptr = (char*)st + align(sizeof(OpusMSEncoder));