From 32024cb5c2074dc97ba9d54f2da540432f1ae474 Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Wed, 25 Jul 2012 01:35:17 -0400
Subject: [PATCH] Adds some histeresis to the stereo saving
This prevents rate reduction due to channel correlation from increasing
by more than 0.25 bit/sample between two frames. This issue was observed
on r.flac where the frame following a transient would lose nearly
1 bit/sample
---
celt/celt.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/celt/celt.c b/celt/celt.c
index 370772dbe..02316bcb6 100644
--- a/celt/celt.c
+++ b/celt/celt.c
@@ -189,6 +189,7 @@ struct OpusCustomEncoder {
opus_int32 vbr_offset;
opus_int32 vbr_count;
opus_val16 overlap_max;
+ opus_val16 stereo_saving;
#ifdef RESYNTH
celt_sig syn_mem[2][2*MAX_PERIOD];
@@ -874,7 +875,7 @@ static int alloc_trim_analysis(const CELTMode *m, const celt_norm *X,
#endif
trim += MAX16(-QCONST16(4.f, 8), MULT16_16_Q15(QCONST16(.75f,15),logXC));
- *stereo_saving = -HALF16(logXC2);
+ *stereo_saving = MIN16(*stereo_saving + QCONST16(0.25f, 8), -HALF16(logXC2));
}
/* Estimate spectral tilt */
@@ -1002,7 +1003,6 @@ int celt_encode_with_ec(CELTEncoder * restrict st, const opus_val16 * pcm, int f
int silence=0;
int tf_chan = 0;
opus_val16 tf_estimate;
- opus_val16 stereo_saving = 0;
int pitch_change=0;
opus_int32 tot_boost=0;
opus_val16 sample_max;
@@ -1595,7 +1595,7 @@ int celt_encode_with_ec(CELTEncoder * restrict st, const opus_val16 * pcm, int f
if (tell+(6<<BITRES) <= total_bits - total_boost)
{
alloc_trim = alloc_trim_analysis(st->mode, X, bandLogE,
- st->end, LM, C, N, &st->analysis, &stereo_saving, tf_estimate, intensity);
+ st->end, LM, C, N, &st->analysis, &st->stereo_saving, tf_estimate, intensity);
ec_enc_icdf(enc, alloc_trim, trim_icdf, 7);
tell = ec_tell_frac(enc);
}
@@ -1623,7 +1623,7 @@ int celt_encode_with_ec(CELTEncoder * restrict st, const opus_val16 * pcm, int f
if (st->constrained_vbr)
target += (st->vbr_offset>>lm_diff);
- /*printf("%f %f %f %f ", st->analysis.activity, st->analysis.tonality, tf_estimate, stereo_saving);*/
+ /*printf("%f %f %f %f %d %d ", st->analysis.activity, st->analysis.tonality, tf_estimate, st->stereo_saving, tot_boost, coded_bands);*/
#ifndef FIXED_POINT
if (st->analysis.valid && st->analysis.activity<.4)
target -= (coded_bins<<BITRES)*1*(.4-st->analysis.activity);
@@ -1635,7 +1635,7 @@ int celt_encode_with_ec(CELTEncoder * restrict st, const opus_val16 * pcm, int f
coded_stereo_bands = IMIN(intensity, coded_bands);
coded_stereo_dof = (st->mode->eBands[coded_stereo_bands]<<LM)-coded_stereo_bands;
/*printf("%d %d %d ", coded_stereo_dof, coded_bins, tot_boost);*/
- target -= MIN32(target/3, SHR16(MULT16_16(stereo_saving,(coded_stereo_dof<<BITRES)),8));
+ target -= MIN32(target/3, SHR16(MULT16_16(st->stereo_saving,(coded_stereo_dof<<BITRES)),8));
target += MULT16_16_Q15(QCONST16(0.035,15),coded_stereo_dof<<BITRES);
}
/* Compensates for the average tonality boost */
--
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