[FFmpeg-cvslog] avcodec/dcaenc: Do not abort process in case of bitrate deficit
Daniil Cherednik
git at videolan.org
Tue May 16 13:22:29 EEST 2017
ffmpeg | branch: master | Daniil Cherednik <dan.cherednik at gmail.com> | Thu May 11 21:12:07 2017 +0000| [9c4e69b8eac8955ce65df2fba2addaeefe81784f] | committer: Rostislav Pehlivanov
avcodec/dcaenc: Do not abort process in case of bitrate deficit
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.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9c4e69b8eac8955ce65df2fba2addaeefe81784f
---
libavcodec/dcaenc.c | 45 +++++++++++++++++++++++++++------------------
1 file changed, 27 insertions(+), 18 deletions(-)
diff --git a/libavcodec/dcaenc.c b/libavcodec/dcaenc.c
index 3af0ec1e75..c1d72bfd16 100644
--- a/libavcodec/dcaenc.c
+++ b/libavcodec/dcaenc.c
@@ -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 */
More information about the ffmpeg-cvslog
mailing list