ref: a4badac92eb367218c74bbb92c89c632df1bc225
parent: 30165bbae0526e1927c418256f29ddde8c665b4e
author: Jean-Marc Valin <[email protected]>
date: Fri Dec 3 10:20:11 EST 2010
Making VBR slightly exceed the budget rather than fail
--- a/libcelt/celt.c
+++ b/libcelt/celt.c
@@ -977,11 +977,11 @@
if (st->vbr_rate_norm>0)
{
celt_word16 alpha;
- celt_int32 delta;
+ celt_int32 delta, tell;
/* The target rate in 8th bits per frame */
celt_int32 vbr_rate;
celt_int32 target;
- celt_int32 vbr_bound, max_allowed;
+ celt_int32 vbr_bound, max_allowed, min_allowed;
target = vbr_rate = M*st->vbr_rate_norm;
@@ -996,9 +996,11 @@
else if (M > 1)
target-=(target+14)/28;
+ tell = ec_enc_tell(enc, BITRES);
+
/* The current offset is removed from the target and the space used
so far is added*/
- target=target+ec_enc_tell(enc, BITRES);
+ target=target+tell;
/* By how much did we "miss" the target on that frame */
delta = target - vbr_rate;
@@ -1005,10 +1007,11 @@
/* Computes the max bit-rate allowed in VBR more to avoid violating the target rate and buffering */
vbr_bound = vbr_rate;
max_allowed = IMIN(vbr_rate+vbr_bound-st->vbr_reservoir>>(BITRES+3),nbAvailableBytes);
+ min_allowed = (tell>>(BITRES+3)) + 2 - nbFilledBytes;
/* In VBR mode the frame size must not be reduced so much that it would result in the encoder running out of bits */
nbAvailableBytes = target+(1<<(BITRES+2))>>(BITRES+3);
- nbAvailableBytes=IMAX(16,IMIN(max_allowed,nbAvailableBytes));
+ nbAvailableBytes=IMAX(min_allowed,IMIN(max_allowed,nbAvailableBytes));
target=nbAvailableBytes<<(BITRES+3);
if (st->vbr_count < 970)