Fixes a SILK bandwidth switching regression
The bug was triggered because f982b84d started using prefill for
SILK bandwidth changes, which reinitialized the encoder state and
prevented the variable lowpass from working properly. To fix the problem,
we preserve the sampling rate and variable low-pass when prefilling.
diff --git a/silk/control_audio_bandwidth.c b/silk/control_audio_bandwidth.c
index 4f9bc5c..f6d22d8 100644
--- a/silk/control_audio_bandwidth.c
+++ b/silk/control_audio_bandwidth.c
@@ -39,9 +39,15 @@
)
{
opus_int fs_kHz;
+ opus_int orig_kHz;
opus_int32 fs_Hz;
- fs_kHz = psEncC->fs_kHz;
+ orig_kHz = psEncC->fs_kHz;
+ /* Handle a bandwidth-switching reset where we need to be aware what the last sampling rate was. */
+ if( orig_kHz == 0 ) {
+ orig_kHz = psEncC->sLP.saved_fs_kHz;
+ }
+ fs_kHz = orig_kHz;
fs_Hz = silk_SMULBB( fs_kHz, 1000 );
if( fs_Hz == 0 ) {
/* Encoder has just been initialized */
@@ -61,7 +67,7 @@
}
if( psEncC->allow_bandwidth_switch || encControl->opusCanSwitch ) {
/* Check if we should switch down */
- if( silk_SMULBB( psEncC->fs_kHz, 1000 ) > psEncC->desiredInternal_fs_Hz )
+ if( silk_SMULBB( orig_kHz, 1000 ) > psEncC->desiredInternal_fs_Hz )
{
/* Switch down */
if( psEncC->sLP.mode == 0 ) {
@@ -76,7 +82,7 @@
psEncC->sLP.mode = 0;
/* Switch to a lower sample frequency */
- fs_kHz = psEncC->fs_kHz == 16 ? 12 : 8;
+ fs_kHz = orig_kHz == 16 ? 12 : 8;
} else {
if( psEncC->sLP.transition_frame_no <= 0 ) {
encControl->switchReady = 1;
@@ -90,12 +96,12 @@
}
else
/* Check if we should switch up */
- if( silk_SMULBB( psEncC->fs_kHz, 1000 ) < psEncC->desiredInternal_fs_Hz )
+ if( silk_SMULBB( orig_kHz, 1000 ) < psEncC->desiredInternal_fs_Hz )
{
/* Switch up */
if( encControl->opusCanSwitch ) {
/* Switch to a higher sample frequency */
- fs_kHz = psEncC->fs_kHz == 8 ? 12 : 16;
+ fs_kHz = orig_kHz == 8 ? 12 : 16;
/* New transition */
psEncC->sLP.transition_frame_no = 0;
diff --git a/silk/enc_API.c b/silk/enc_API.c
index 7ae31a9..55a33f3 100644
--- a/silk/enc_API.c
+++ b/silk/enc_API.c
@@ -200,15 +200,25 @@
tot_blocks = ( nBlocksOf10ms > 1 ) ? nBlocksOf10ms >> 1 : 1;
curr_block = 0;
if( prefillFlag ) {
+ silk_LP_state save_LP;
/* Only accept input length of 10 ms */
if( nBlocksOf10ms != 1 ) {
celt_assert( 0 );
RESTORE_STACK;
return SILK_ENC_INPUT_INVALID_NO_OF_SAMPLES;
}
+ if ( prefillFlag == 2 ) {
+ save_LP = psEnc->state_Fxx[ 0 ].sCmn.sLP;
+ /* Save the sampling rate so the bandwidth switching code can keep handling transitions. */
+ save_LP.saved_fs_kHz = psEnc->state_Fxx[ 0 ].sCmn.fs_kHz;
+ }
/* Reset Encoder */
for( n = 0; n < encControl->nChannelsInternal; n++ ) {
ret = silk_init_encoder( &psEnc->state_Fxx[ n ], psEnc->state_Fxx[ n ].sCmn.arch );
+ /* Restore the variable LP state. */
+ if ( prefillFlag == 2 ) {
+ psEnc->state_Fxx[ n ].sCmn.sLP = save_LP;
+ }
celt_assert( !ret );
}
tmp_payloadSize_ms = encControl->payloadSize_ms;
diff --git a/silk/structs.h b/silk/structs.h
index 4ff590b..3380c75 100644
--- a/silk/structs.h
+++ b/silk/structs.h
@@ -78,6 +78,7 @@
opus_int32 In_LP_State[ 2 ]; /* Low pass filter state */
opus_int32 transition_frame_no; /* Counter which is mapped to a cut-off frequency */
opus_int mode; /* Operating mode, <0: switch down, >0: switch up; 0: do nothing */
+ opus_int32 saved_fs_kHz; /* If non-zero, holds the last sampling rate before a bandwidth switching reset. */
} silk_LP_state;
/* Structure containing NLSF codebook */
diff --git a/src/opus_encoder.c b/src/opus_encoder.c
index 0be65a3..e6cca90 100644
--- a/src/opus_encoder.c
+++ b/src/opus_encoder.c
@@ -1599,7 +1599,8 @@
redundancy = 1;
celt_to_silk = 1;
st->silk_bw_switch = 0;
- prefill=1;
+ /* Do a prefill without reseting the sampling rate control. */
+ prefill=2;
}
/* If we decided to go with CELT, make sure redundancy is off, no matter what
@@ -1825,7 +1826,9 @@
for (i=0;i<st->encoder_buffer*st->channels;i++)
pcm_silk[i] = FLOAT2INT16(st->delay_buffer[i]);
#endif
- silk_Encode( silk_enc, &st->silk_mode, pcm_silk, st->encoder_buffer, NULL, &zero, 1, activity );
+ silk_Encode( silk_enc, &st->silk_mode, pcm_silk, st->encoder_buffer, NULL, &zero, prefill, activity );
+ /* Prevent a second switch in the real encode call. */
+ st->silk_mode.opusCanSwitch = 0;
}
#ifdef FIXED_POINT
