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Terminate the coding of skip bits at the last dynalloc boosted band. Otherwise the bitstream allows non-sensible behavior by the encoder (dynallocing bits into a band and then skipping it). This reduces skip bit overhead by about 2-3% at moderate bitrates with the current encoder.

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Gregory Maxwell 2010-12-16 14:22:51 -05:00 • committed by Jean-Marc Valin
parent 034172baa6
commit 8e4476789c
1 changed files with 7 additions and 3 deletions
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10
libcelt/rate.c
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@ -140,7 +140,7 @@ void compute_pulse_cache(CELTMode *m, int LM)
#define ALLOC_STEPS 6 #define ALLOC_STEPS 6
static inline int interp_bits2pulses(const CELTMode *m, int start, int end, static inline int interp_bits2pulses(const CELTMode *m, int start, int end, int skip_start,
const int *bits1, const int *bits2, const int *thresh, int total, int *bits, const int *bits1, const int *bits2, const int *thresh, int total, int *bits,
int *ebits, int *fine_priority, int len, int _C, int LM, void *ec, int encode, int prev) int *ebits, int *fine_priority, int len, int _C, int LM, void *ec, int encode, int prev)
{ {
@ -221,7 +221,7 @@ static inline int interp_bits2pulses(const CELTMode *m, int start, int end,
This means we won't be using the extra bit we reserved to signal the This means we won't be using the extra bit we reserved to signal the
end of manual skipping, but that will get added back in by end of manual skipping, but that will get added back in by
quant_all_bands().*/ quant_all_bands().*/
if (j<=start) if (j<=skip_start)
break; break;
rem = IMAX(left-(m->eBands[j]-m->eBands[start]),0); rem = IMAX(left-(m->eBands[j]-m->eBands[start]),0);
band_width = m->eBands[codedBands]-m->eBands[j]; band_width = m->eBands[codedBands]-m->eBands[j];
@ -363,6 +363,7 @@ int compute_allocation(const CELTMode *m, int start, int end, const int *offsets
int lo, hi, len, j; int lo, hi, len, j;
const int C = CHANNELS(_C); const int C = CHANNELS(_C);
int codedBands; int codedBands;
int skip_start;
VARDECL(int, bits1); VARDECL(int, bits1);
VARDECL(int, bits2); VARDECL(int, bits2);
VARDECL(int, thresh); VARDECL(int, thresh);
@ -371,6 +372,7 @@ int compute_allocation(const CELTMode *m, int start, int end, const int *offsets
total = IMAX(total, 0); total = IMAX(total, 0);
len = m->nbEBands; len = m->nbEBands;
skip_start = start;
ALLOC(bits1, len, int); ALLOC(bits1, len, int);
ALLOC(bits2, len, int); ALLOC(bits2, len, int);
ALLOC(thresh, len, int); ALLOC(thresh, len, int);
@ -424,8 +426,10 @@ int compute_allocation(const CELTMode *m, int start, int end, const int *offsets
if (bits1[j] < 0) if (bits1[j] < 0)
bits1[j] = 0; bits1[j] = 0;
bits1[j] += offsets[j]; bits1[j] += offsets[j];
if (offsets[j]>0)
skip_start = j;
} }
codedBands = interp_bits2pulses(m, start, end, bits1, bits2, thresh, codedBands = interp_bits2pulses(m, start, end, skip_start, bits1, bits2, thresh,
total, pulses, ebits, fine_priority, len, C, LM, ec, encode, prev); total, pulses, ebits, fine_priority, len, C, LM, ec, encode, prev);
RESTORE_STACK; RESTORE_STACK;
return codedBands; return codedBands;