Moving FEC decision to the Opus encoder level (from SILK level)
diff --git a/silk/control.h b/silk/control.h
index dfbead9..b76ec33 100644
--- a/silk/control.h
+++ b/silk/control.h
@@ -77,6 +77,9 @@
/* I: Flag to enable in-band Forward Error Correction (FEC); 0/1 */
opus_int useInBandFEC;
+ /* I: Flag to actually code in-band Forward Error Correction (FEC) in the current packet; 0/1 */
+ opus_int LBRR_coded;
+
/* I: Flag to enable discontinuous transmission (DTX); 0/1 */
opus_int useDTX;
diff --git a/silk/control_codec.c b/silk/control_codec.c
index e21b361..9350fd4 100644
--- a/silk/control_codec.c
+++ b/silk/control_codec.c
@@ -57,7 +57,7 @@
static OPUS_INLINE opus_int silk_setup_LBRR(
silk_encoder_state *psEncC, /* I/O */
- const opus_int32 TargetRate_bps /* I */
+ const silk_EncControlStruct *encControl /* I */
);
@@ -65,7 +65,6 @@
opus_int silk_control_encoder(
silk_encoder_state_Fxx *psEnc, /* I/O Pointer to Silk encoder state */
silk_EncControlStruct *encControl, /* I Control structure */
- const opus_int32 TargetRate_bps, /* I Target max bitrate (bps) */
const opus_int allow_bw_switch, /* I Flag to allow switching audio bandwidth */
const opus_int channelNb, /* I Channel number */
const opus_int force_fs_kHz
@@ -125,7 +124,7 @@
/********************************************/
/* Set LBRR usage */
/********************************************/
- ret += silk_setup_LBRR( &psEnc->sCmn, TargetRate_bps );
+ ret += silk_setup_LBRR( &psEnc->sCmn, encControl );
psEnc->sCmn.controlled_since_last_payload = 1;
@@ -403,33 +402,20 @@
static OPUS_INLINE opus_int silk_setup_LBRR(
silk_encoder_state *psEncC, /* I/O */
- const opus_int32 TargetRate_bps /* I */
+ const silk_EncControlStruct *encControl /* I */
)
{
opus_int LBRR_in_previous_packet, ret = SILK_NO_ERROR;
- opus_int32 LBRR_rate_thres_bps;
LBRR_in_previous_packet = psEncC->LBRR_enabled;
- psEncC->LBRR_enabled = 0;
- if( psEncC->useInBandFEC && psEncC->PacketLoss_perc > 0 ) {
- if( psEncC->fs_kHz == 8 ) {
- LBRR_rate_thres_bps = LBRR_NB_MIN_RATE_BPS;
- } else if( psEncC->fs_kHz == 12 ) {
- LBRR_rate_thres_bps = LBRR_MB_MIN_RATE_BPS;
+ psEncC->LBRR_enabled = encControl->LBRR_coded;
+ if( psEncC->LBRR_enabled ) {
+ /* Set gain increase for coding LBRR excitation */
+ if( LBRR_in_previous_packet == 0 ) {
+ /* Previous packet did not have LBRR, and was therefore coded at a higher bitrate */
+ psEncC->LBRR_GainIncreases = 7;
} else {
- LBRR_rate_thres_bps = LBRR_WB_MIN_RATE_BPS;
- }
- LBRR_rate_thres_bps = silk_SMULWB( silk_MUL( LBRR_rate_thres_bps, 125 - silk_min( psEncC->PacketLoss_perc, 25 ) ), SILK_FIX_CONST( 0.01, 16 ) );
-
- if( TargetRate_bps > LBRR_rate_thres_bps ) {
- /* Set gain increase for coding LBRR excitation */
- if( LBRR_in_previous_packet == 0 ) {
- /* Previous packet did not have LBRR, and was therefore coded at a higher bitrate */
- psEncC->LBRR_GainIncreases = 7;
- } else {
- psEncC->LBRR_GainIncreases = silk_max_int( 7 - silk_SMULWB( (opus_int32)psEncC->PacketLoss_perc, SILK_FIX_CONST( 0.4, 16 ) ), 2 );
- }
- psEncC->LBRR_enabled = 1;
+ psEncC->LBRR_GainIncreases = silk_max_int( 7 - silk_SMULWB( (opus_int32)psEncC->PacketLoss_perc, SILK_FIX_CONST( 0.4, 16 ) ), 2 );
}
}
diff --git a/silk/enc_API.c b/silk/enc_API.c
index 8079b7d..ba3db06 100644
--- a/silk/enc_API.c
+++ b/silk/enc_API.c
@@ -237,7 +237,7 @@
for( n = 0; n < encControl->nChannelsInternal; n++ ) {
/* Force the side channel to the same rate as the mid */
opus_int force_fs_kHz = (n==1) ? psEnc->state_Fxx[0].sCmn.fs_kHz : 0;
- if( ( ret = silk_control_encoder( &psEnc->state_Fxx[ n ], encControl, TargetRate_bps, psEnc->allowBandwidthSwitch, n, force_fs_kHz ) ) != 0 ) {
+ if( ( ret = silk_control_encoder( &psEnc->state_Fxx[ n ], encControl, psEnc->allowBandwidthSwitch, n, force_fs_kHz ) ) != 0 ) {
silk_assert( 0 );
RESTORE_STACK;
return ret;
diff --git a/silk/fixed/main_FIX.h b/silk/fixed/main_FIX.h
index 57f799c..ddbf377 100644
--- a/silk/fixed/main_FIX.h
+++ b/silk/fixed/main_FIX.h
@@ -81,7 +81,6 @@
opus_int silk_control_encoder(
silk_encoder_state_Fxx *psEnc, /* I/O Pointer to Silk encoder state */
silk_EncControlStruct *encControl, /* I Control structure */
- const opus_int32 TargetRate_bps, /* I Target max bitrate (bps) */
const opus_int allow_bw_switch, /* I Flag to allow switching audio bandwidth */
const opus_int channelNb, /* I Channel number */
const opus_int force_fs_kHz
diff --git a/silk/float/main_FLP.h b/silk/float/main_FLP.h
index 5ea1445..8d1d2a8 100644
--- a/silk/float/main_FLP.h
+++ b/silk/float/main_FLP.h
@@ -79,7 +79,6 @@
opus_int silk_control_encoder(
silk_encoder_state_FLP *psEnc, /* I/O Pointer to Silk encoder state FLP */
silk_EncControlStruct *encControl, /* I Control structure */
- const opus_int32 TargetRate_bps, /* I Target max bitrate (bps) */
const opus_int allow_bw_switch, /* I Flag to allow switching audio bandwidth */
const opus_int channelNb, /* I Channel number */
const opus_int force_fs_kHz
diff --git a/src/opus_encoder.c b/src/opus_encoder.c
index 59db441..623b40f 100644
--- a/src/opus_encoder.c
+++ b/src/opus_encoder.c
@@ -156,6 +156,14 @@
{ 36000, 16000}, /* stereo */
};
+static const opus_int32 fec_thresholds[] = {
+ 12000, 1000, /* NB */
+ 14000, 1000, /* MB */
+ 16000, 1000, /* WB */
+ 20000, 1000, /* SWB */
+ 22000, 1000, /* FB */
+};
+
int opus_encoder_get_size(int channels)
{
int silkEncSizeBytes, celtEncSizeBytes;
@@ -947,6 +955,39 @@
return EXTRACT16(MIN32(Q15ONE, MULT16_16(20, mem->max_follower)));
}
+static int decide_fec(int useInBandFEC, int PacketLoss_perc, int last_fec, int mode, int *bandwidth, opus_int32 rate)
+{
+ int orig_bandwidth;
+ if (!useInBandFEC || PacketLoss_perc == 0 || mode == MODE_CELT_ONLY)
+ return 0;
+ orig_bandwidth = *bandwidth;
+ for (;;)
+ {
+ opus_int32 hysteresis;
+ opus_int32 LBRR_rate_thres_bps;
+ /* Compute threshold for using FEC at the current bandwidth setting */
+ LBRR_rate_thres_bps = fec_thresholds[2*(*bandwidth - OPUS_BANDWIDTH_NARROWBAND)];
+ hysteresis = fec_thresholds[2*(*bandwidth - OPUS_BANDWIDTH_NARROWBAND) + 1];
+ if (last_fec == 1) LBRR_rate_thres_bps -= hysteresis;
+ if (last_fec == 0) LBRR_rate_thres_bps += hysteresis;
+ LBRR_rate_thres_bps = silk_SMULWB( silk_MUL( LBRR_rate_thres_bps,
+ 125 - silk_min( PacketLoss_perc, 25 ) ), SILK_FIX_CONST( 0.01, 16 ) );
+ /* If loss <= 5%, we look at whether we have enough rate to enable FEC.
+ If loss > 5%, we decrease the bandwidth until we can enable FEC. */
+ if (rate > LBRR_rate_thres_bps)
+ return 1;
+ else if (PacketLoss_perc <= 5)
+ return 0;
+ else if (*bandwidth > OPUS_BANDWIDTH_NARROWBAND)
+ (*bandwidth)--;
+ else
+ break;
+ }
+ /* Couldn't find any bandwidth to enable FEC, keep original bandwidth. */
+ *bandwidth = orig_bandwidth;
+ return 0;
+}
+
static int compute_silk_rate_for_hybrid(int rate, int bandwidth, int frame20ms, int vbr) {
int entry;
int i;
@@ -1537,6 +1578,8 @@
st->bandwidth = IMIN(st->bandwidth, st->detected_bandwidth);
}
#endif
+ st->silk_mode.LBRR_coded = decide_fec(st->silk_mode.useInBandFEC, st->silk_mode.packetLossPercentage,
+ st->silk_mode.LBRR_coded, st->mode, &st->bandwidth, equiv_rate);
celt_encoder_ctl(celt_enc, OPUS_SET_LSB_DEPTH(lsb_depth));
/* CELT mode doesn't support mediumband, use wideband instead */
