Commit 243ff0c6 authored by Jean-Marc Valin's avatar Jean-Marc Valin
Browse files

comments

parent 0734cad5
......@@ -118,10 +118,12 @@ int opus_encode(OpusEncoder *st, const short *pcm, int frame_size,
int to_celt = 0;
celt_int32 mono_rate;
/* Rete-dependent mono-stereo decision */
if (st->channels == 2)
{
celt_int32 decision_rate;
decision_rate = st->bitrate_bps + st->voice_ratio*st->voice_ratio;
/* Add some hysteresis */
if (st->stream_channels == 2)
decision_rate += 4000;
else
......@@ -145,7 +147,9 @@ int opus_encode(OpusEncoder *st, const short *pcm, int frame_size,
if (st->user_mode==OPUS_MODE_AUTO)
{
celt_int32 decision_rate;
/* SILK/CELT threshold is higher for voice than for music */
decision_rate = mono_rate - 3*st->voice_ratio*st->voice_ratio;
/* Hysteresis */
if (st->prev_mode == MODE_CELT_ONLY)
decision_rate += 4000;
else if (st->prev_mode>0)
......@@ -161,7 +165,7 @@ int opus_encode(OpusEncoder *st, const short *pcm, int frame_size,
st->mode = MODE_CELT_ONLY;
}
/* Bandwidth selection */
/* Automatic (rate-dependent) bandwidth selection */
if (st->mode == MODE_CELT_ONLY)
{
if (mono_rate>35000 || (mono_rate>28000 && st->bandwidth==BANDWIDTH_FULLBAND))
......@@ -184,10 +188,14 @@ int opus_encode(OpusEncoder *st, const short *pcm, int frame_size,
st->bandwidth = BANDWIDTH_MEDIUMBAND;
else
st->bandwidth = BANDWIDTH_NARROWBAND;
/* Prevents any transition to SWB/FB until the SILK layer has fully
switched to WB mode and turned the variable LP filter off */
if (!st->silk_mode.inWBmodeWithoutVariableLP && st->bandwidth > BANDWIDTH_WIDEBAND)
st->bandwidth = BANDWIDTH_WIDEBAND;
}
/* Prevents Opus from wasting bits on frequencies that are above
the Nyquist rate of the input signal */
if (st->Fs <= 24000 && st->bandwidth > BANDWIDTH_SUPERWIDEBAND)
st->bandwidth = BANDWIDTH_SUPERWIDEBAND;
if (st->Fs <= 16000 && st->bandwidth > BANDWIDTH_WIDEBAND)
......@@ -200,7 +208,7 @@ int opus_encode(OpusEncoder *st, const short *pcm, int frame_size,
if (st->user_bandwidth != BANDWIDTH_AUTO)
st->bandwidth = st->user_bandwidth;
/* Preventing non-sensical configurations */
/* Prevents nonsensical configurations, i.e. modes that don't exist */
if (frame_size < st->Fs/100 && st->mode != MODE_CELT_ONLY)
st->mode = MODE_CELT_ONLY;
if (frame_size > st->Fs/50 && st->mode != MODE_SILK_ONLY)
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment