From 1f65994ef428520534630d5d706c91fb1d690938 Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Sun, 9 Oct 2011 01:05:25 -0400
Subject: [PATCH] Avoids unnecessary collapse of the HF stereo image in hybrid
mode.
SILK now reports an "effective width" that takes into account side prediction.
---
silk/enc_API.c | 2 +-
silk/stereo_LR_to_MS.c | 15 +++++++++++++++
silk/structs.h | 1 +
3 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/silk/enc_API.c b/silk/enc_API.c
index 4702401b4..cd4d960cb 100644
--- a/silk/enc_API.c
+++ b/silk/enc_API.c
@@ -452,7 +452,7 @@ opus_int silk_Encode(
encControl->allowBandwidthSwitch = psEnc->allowBandwidthSwitch;
encControl->inWBmodeWithoutVariableLP = psEnc->state_Fxx[ 0 ].sCmn.fs_kHz == 16 && psEnc->state_Fxx[ 0 ].sCmn.sLP.mode == 0;
encControl->internalSampleRate = silk_SMULBB( psEnc->state_Fxx[ 0 ].sCmn.fs_kHz, 1000 );
- encControl->stereoWidth_Q14 = psEnc->sStereo.width_prev_Q14;
+ encControl->stereoWidth_Q14 = psEnc->sStereo.effective_width_prev_Q14;
if( prefillFlag ) {
encControl->payloadSize_ms = tmp_payloadSize_ms;
encControl->complexity = tmp_complexity;
diff --git a/silk/stereo_LR_to_MS.c b/silk/stereo_LR_to_MS.c
index 7fbb3ae7a..24f4800c5 100644
--- a/silk/stereo_LR_to_MS.c
+++ b/silk/stereo_LR_to_MS.c
@@ -53,6 +53,7 @@ void silk_stereo_LR_to_MS(
opus_int16 LP_mid[ MAX_FRAME_LENGTH ], HP_mid[ MAX_FRAME_LENGTH ];
opus_int16 LP_side[ MAX_FRAME_LENGTH ], HP_side[ MAX_FRAME_LENGTH ];
opus_int16 *mid = &x1[ -2 ];
+ opus_int16 effective_pred=0;
/* Convert to basic mid/side signals */
for( n = 0; n < frame_length + 2; n++ ) {
@@ -139,6 +140,7 @@ void silk_stereo_LR_to_MS(
silk_stereo_quant_pred( pred_Q13, ix );
/* Collapse stereo width */
width_Q14 = 0;
+ effective_pred = silk_abs( pred_Q13[ 0 ] ) + silk_abs( pred_Q13[ 1 ] );
pred_Q13[ 0 ] = 0;
pred_Q13[ 1 ] = 0;
mid_side_rates_bps[ 0 ] = total_rate_bps;
@@ -154,6 +156,7 @@ void silk_stereo_LR_to_MS(
silk_stereo_quant_pred( pred_Q13, ix );
/* Collapse stereo width */
width_Q14 = 0;
+ effective_pred = silk_abs( pred_Q13[ 0 ] ) + silk_abs( pred_Q13[ 1 ] );
pred_Q13[ 0 ] = 0;
pred_Q13[ 1 ] = 0;
} else if( state->smth_width_Q14 > SILK_FIX_CONST( 0.95, 14 ) ) {
@@ -166,6 +169,7 @@ void silk_stereo_LR_to_MS(
pred_Q13[ 1 ] = silk_RSHIFT( silk_SMULBB( state->smth_width_Q14, pred_Q13[ 1 ] ), 14 );
silk_stereo_quant_pred( pred_Q13, ix );
width_Q14 = state->smth_width_Q14;
+ effective_pred = silk_abs( pred_Q13[ 0 ] ) + silk_abs( pred_Q13[ 1 ] );
}
if (*mid_only_flag == 0 && mid_side_rates_bps[ 1 ] < 1)
@@ -210,4 +214,15 @@ void silk_stereo_LR_to_MS(
state->pred_prev_Q13[ 0 ] = (opus_int16)pred_Q13[ 0 ];
state->pred_prev_Q13[ 1 ] = (opus_int16)pred_Q13[ 1 ];
state->width_prev_Q14 = (opus_int16)width_Q14;
+ {
+ /* Evaluate the effective width of the SILK stereo so we can report it
+ for the CELT layer to partially collapse the image. We need to take
+ into account the prediction otherwise we risk compeltely collapsing
+ the HF image when doing panned mono */
+ opus_int32 effective_width;
+ effective_width = (opus_int32)state->width_prev_Q14 + silk_LSHIFT32( (opus_int32)effective_pred, 1);
+ effective_width += silk_RSHIFT( effective_width, 2 );
+ effective_width = silk_min_32(effective_width, 16384);
+ state->effective_width_prev_Q14 = effective_width;
+ }
}
diff --git a/silk/structs.h b/silk/structs.h
index 70c81baee..10a3546c5 100644
--- a/silk/structs.h
+++ b/silk/structs.h
@@ -101,6 +101,7 @@ typedef struct {
opus_int32 mid_side_amp_Q0[ 4 ];
opus_int16 smth_width_Q14;
opus_int16 width_prev_Q14;
+ opus_int16 effective_width_prev_Q14;
opus_int8 predIx[ MAX_FRAMES_PER_PACKET ][ 2 ][ 3 ];
opus_int8 mid_only_flags[ MAX_FRAMES_PER_PACKET ];
} stereo_enc_state;
--
GitLab