From 59618a5fa202799b98720f2289227edb06a0f9c4 Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
Date: Mon, 16 Nov 2015 23:03:17 -0500
Subject: [PATCH] Quality: removes VBR attenuation at low bitrate
Turns out that even low bitrates benefit from VBR
---
celt/celt_encoder.c | 18 ++++--------------
1 file changed, 4 insertions(+), 14 deletions(-)
diff --git a/celt/celt_encoder.c b/celt/celt_encoder.c
index 3ee7a4d3f..1c6128a2e 100644
--- a/celt/celt_encoder.c
+++ b/celt/celt_encoder.c
@@ -1279,21 +1279,11 @@ static int compute_vbr(const CELTMode *mode, AnalysisInfo *analysis, opus_int32
/*printf("%f %d\n", maxDepth, floor_depth);*/
}
- if ((!has_surround_mask||lfe) && (constrained_vbr || bitrate<64000))
+ /* Make VBR less aggressive for constrained VBR because we can't keep a higher bitrate
+ for long. Needs tuning. */
+ if ((!has_surround_mask||lfe) && constrained_vbr)
{
- opus_val16 rate_factor = Q15ONE;
- if (bitrate < 64000)
- {
-#ifdef FIXED_POINT
- rate_factor = MAX16(0,(bitrate-32000));
-#else
- rate_factor = MAX16(0,(1.f/32768)*(bitrate-32000));
-#endif
- }
- if (constrained_vbr)
- rate_factor = MIN16(rate_factor, QCONST16(0.67f, 15));
- target = base_target + (opus_int32)MULT16_32_Q15(rate_factor, target-base_target);
-
+ target = base_target + (opus_int32)MULT16_32_Q15(QCONST16(0.67f, 15), target-base_target);
}
if (!has_surround_mask && tf_estimate < QCONST16(.2f, 14))
--
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