ref: 2b627e12e5587e8cdefed0137b41fb5cac492e8a
parent: 416dc73f280809c30a8162a715f5f84ca82176d5
author: Jean-Marc Valin <[email protected]>
date: Fri Jul 27 10:28:21 EDT 2012
Makes VBR rate variations less aggressive at low bit-rates and for CVBR
--- a/celt/celt.c
+++ b/celt/celt.c
@@ -1565,10 +1565,6 @@
{int effectiveRate;
- /* Always use MS for 2.5 ms frames until we can do a better analysis */
- if (LM!=0)
- dual_stereo = stereo_analysis(st->mode, X, LM, N);
-
static const opus_val16 intensity_thresholds[21]=
/* 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 off*/
{ 16,21,23,25,27,29,31,33,35,38,42,46,50,54,58,63,68,75,84,102,130};@@ -1575,6 +1571,10 @@
static const opus_val16 intensity_histeresis[21]=
{ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 4, 5, 6, 8, 12};+ /* Always use MS for 2.5 ms frames until we can do a better analysis */
+ if (LM!=0)
+ dual_stereo = stereo_analysis(st->mode, X, LM, N);
+
/* Account for coarse energy */
effectiveRate = (8*effectiveBytes - 80)>>LM;
@@ -1600,7 +1600,7 @@
opus_val16 alpha;
opus_int32 delta;
/* The target rate in 8th bits per frame */
- opus_int32 target, new_target;
+ opus_int32 target, base_target;
opus_int32 min_allowed;
int coded_bins;
int coded_bands;
@@ -1614,6 +1614,8 @@
The CELT allocator will just not be able to use more than that anyway. */
nbCompressedBytes = IMIN(nbCompressedBytes,1275>>(3-LM));
target = vbr_rate - ((40*C+20)<<BITRES);
+ base_target = target;
+
if (st->constrained_vbr)
target += (st->vbr_offset>>lm_diff);
@@ -1622,6 +1624,7 @@
if (st->analysis.valid && st->analysis.activity<.4)
target -= (coded_bins<<BITRES)*1*(.4-st->analysis.activity);
#endif
+ /* Stereo savings */
if (C==2)
{int coded_stereo_bands;
@@ -1638,19 +1641,20 @@
target += tot_boost;
/* Compensates for the average transient boost */
target = MULT16_32_Q15(QCONST16(0.96f,15),target);
+ /* Apply transient boost */
+ target = SHL32(MULT16_32_Q15(tf_estimate, target),1);
- new_target = SHL32(MULT16_32_Q15(tf_estimate, target),1);
-
#ifndef FIXED_POINT
+ /* Apply tonality boost */
if (st->analysis.valid) {int tonal_target;
float tonal;
tonal = MAX16(0,st->analysis.tonality-.2);
- tonal_target = new_target + (coded_bins<<BITRES)*2.0f*tonal;
+ tonal_target = target + (coded_bins<<BITRES)*2.0f*tonal;
if (pitch_change)
tonal_target += (coded_bins<<BITRES)*.8;
/*printf("%f %f ", st->analysis.tonality, tonal);*/- new_target = IMAX(tonal_target,new_target);
+ target = IMAX(tonal_target,target);
}
#endif
@@ -1660,13 +1664,30 @@
bins = st->mode->eBands[st->mode->nbEBands-2]<<LM;
/*floor_depth = SHR32(MULT16_16((C*bins<<BITRES),celt_log2(SHL32(MAX16(1,sample_max),13))), DB_SHIFT);*/
floor_depth = SHR32(MULT16_16((C*bins<<BITRES),maxDepth), DB_SHIFT);
- floor_depth = IMAX(floor_depth, new_target>>2);
- new_target = IMIN(new_target, floor_depth);
+ floor_depth = IMAX(floor_depth, target>>2);
+ target = IMIN(target, floor_depth);
/*printf("%f %d\n", maxDepth, floor_depth);*/}
+
+ if (st->constrained_vbr || st->bitrate<64000)
+ {+ opus_val16 rate_factor;
+#ifdef FIXED_POINT
+ rate_factor = MAX16(0,(st->bitrate-32000));
+#else
+ rate_factor = MAX16(0,(1.f/32768)*(st->bitrate-32000));
+#endif
+ if (st->constrained_vbr)
+ rate_factor = MIN16(rate_factor, QCONST16(0.67f, 15));
+ target = base_target + MULT16_32_Q15(rate_factor, target-base_target);
+
+ }
+ /* Don't allow more than doubling the rate */
+ target = IMIN(2*base_target, target);
+
/* The current offset is removed from the target and the space used
so far is added*/
- target=new_target+tell;
+ target=target+tell;
/* In VBR mode the frame size must not be reduced so much that it would
result in the encoder running out of bits.
The margin of 2 bytes ensures that none of the bust-prevention logic