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Code Issues Releases Activity

avcodec/dcaenc: Do not abort process in case of bitrate deficit

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Old behaviour - abort if at least one subband has 1bit quantizer
and consumed_bits still greater than frame_bits size. It was
a bit strange - we still could reduce bits consumption by reducing
SNR for other subbands. Same strange logic with upper threshold -
stop bits allocation if at least one subband reach 26bits.

New behaviour - if consumed_bits greater than frame_bits and all
subbands has 1 bit quantizer we restart bits allocation and allow
zero subbands.
This commit is contained in:
Daniil Cherednik 2017-05-11 21:12:07 +00:00 committed by Rostislav Pehlivanov
parent 8e7e74df93
commit 9c4e69b8ea
1 changed files with 27 additions and 18 deletions
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45
libavcodec/dcaenc.c
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@ -656,7 +656,6 @@ static void adpcm_analysis(DCAEncContext *c)
static const int snr_fudge = 128;
#define USED_1ABITS 1
#define USED_NABITS 2
#define USED_26ABITS 4
static inline int32_t get_step_size(const DCAEncContext *c, int ch, int band)
@ -794,7 +793,7 @@ static uint32_t set_best_abits_code(int abits[DCAENC_SUBBANDS], int bands, int32
/* Check do we have subband which cannot be encoded by Huffman tables */
for (i = 0; i < bands; i++) {
if (abits[i] > 12) {
if (abits[i] > 12 || abits[i] == 0) {
*res = best_sel;
return best_bits;
}
@ -812,9 +811,9 @@ static uint32_t set_best_abits_code(int abits[DCAENC_SUBBANDS], int bands, int32
return best_bits;
}
static int init_quantization_noise(DCAEncContext *c, int noise)
static int init_quantization_noise(DCAEncContext *c, int noise, int forbid_zero)
{
int ch, band, ret = 0;
int ch, band, ret = USED_26ABITS | USED_1ABITS;
uint32_t huff_bit_count_accum[MAX_CHANNELS][DCA_CODE_BOOKS][7];
uint32_t clc_bit_count_accum[MAX_CHANNELS][DCA_CODE_BOOKS];
uint32_t bits_counter = 0;
@ -831,16 +830,19 @@ static int init_quantization_noise(DCAEncContext *c, int noise)
if (snr_cb >= 1312) {
c->abits[ch][band] = 26;
ret |= USED_26ABITS;
ret &= ~USED_1ABITS;
} else if (snr_cb >= 222) {
c->abits[ch][band] = 8 + mul32(snr_cb - 222, 69000000);
ret |= USED_NABITS;
ret &= ~(USED_26ABITS | USED_1ABITS);
} else if (snr_cb >= 0) {
c->abits[ch][band] = 2 + mul32(snr_cb, 106000000);
ret |= USED_NABITS;
} else {
ret &= ~(USED_26ABITS | USED_1ABITS);
} else if (forbid_zero || snr_cb >= -140) {
c->abits[ch][band] = 1;
ret |= USED_1ABITS;
ret &= ~USED_26ABITS;
} else {
c->abits[ch][band] = 0;
ret &= ~(USED_26ABITS | USED_1ABITS);
}
}
c->consumed_bits += set_best_abits_code(c->abits[ch], 32, &c->bit_allocation_sel[ch]);
@ -888,15 +890,19 @@ static void assign_bits(DCAEncContext *c)
/* Find the bounds where the binary search should work */
int low, high, down;
int used_abits = 0;
init_quantization_noise(c, c->worst_quantization_noise);
int forbid_zero = 1;
restart:
init_quantization_noise(c, c->worst_quantization_noise, forbid_zero);
low = high = c->worst_quantization_noise;
if (c->consumed_bits > c->frame_bits) {
while (c->consumed_bits > c->frame_bits) {
av_assert0(used_abits != USED_1ABITS);
if (used_abits == USED_1ABITS && forbid_zero) {
forbid_zero = 0;
goto restart;
}
low = high;
high += snr_fudge;
used_abits = init_quantization_noise(c, high);
used_abits = init_quantization_noise(c, high, forbid_zero);
}
} else {
while (c->consumed_bits <= c->frame_bits) {
@ -904,17 +910,17 @@ static void assign_bits(DCAEncContext *c)
if (used_abits == USED_26ABITS)
goto out; /* The requested bitrate is too high, pad with zeros */
low -= snr_fudge;
used_abits = init_quantization_noise(c, low);
used_abits = init_quantization_noise(c, low, forbid_zero);
}
}
/* Now do a binary search between low and high to see what fits */
for (down = snr_fudge >> 1; down; down >>= 1) {
init_quantization_noise(c, high - down);
init_quantization_noise(c, high - down, forbid_zero);
if (c->consumed_bits <= c->frame_bits)
high -= down;
}
init_quantization_noise(c, high);
init_quantization_noise(c, high, forbid_zero);
out:
c->worst_quantization_noise = high;
if (high > c->worst_noise_ever)
@ -1173,13 +1179,15 @@ static void put_subframe(DCAEncContext *c, int subframe)
/* Transition mode: none for each channel and subband */
for (ch = 0; ch < c->fullband_channels; ch++)
for (band = 0; band < DCAENC_SUBBANDS; band++)
put_bits(&c->pb, 1, 0); /* codebook A4 */
if (c->abits[ch][band])
put_bits(&c->pb, 1, 0); /* codebook A4 */
}
/* Scale factors */
for (ch = 0; ch < c->fullband_channels; ch++)
for (band = 0; band < DCAENC_SUBBANDS; band++)
put_bits(&c->pb, 7, c->scale_factor[ch][band]);
if (c->abits[ch][band])
put_bits(&c->pb, 7, c->scale_factor[ch][band]);
/* Joint subband scale factor codebook select: not transmitted */
/* Scale factors for joint subband coding: not transmitted */
@ -1199,6 +1207,7 @@ static void put_subframe(DCAEncContext *c, int subframe)
for (ss = 0; ss < SUBSUBFRAMES ; ss++)
for (ch = 0; ch < c->fullband_channels; ch++)
for (band = 0; band < DCAENC_SUBBANDS; band++)
if (c->abits[ch][band])
put_subframe_samples(c, ss, band, ch);
/* DSYNC */