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ffmpeg/libavcodec/g722.c
Martin Storsjö 8bd1956462 g722: Move the low_inv_quant6 table up to the common tables 
Since SVN rev 25866, this table is used by the trellis encoder, too,
not only by the decoder.

Originally committed as revision 26065 to svn://svn.ffmpeg.org/ffmpeg/trunk
2010-12-21 09:03:57 +00:00

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/*
* G.722 ADPCM audio encoder/decoder
*
* Copyright (c) CMU 1993 Computer Science, Speech Group
* Chengxiang Lu and Alex Hauptmann
* Copyright (c) 2005 Steve Underwood <steveu at coppice.org>
* Copyright (c) 2009 Kenan Gillet
* Copyright (c) 2010 Martin Storsjo
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
*
* G.722 ADPCM audio codec
*
* This G.722 decoder is a bit-exact implementation of the ITU G.722
* specification for all three specified bitrates - 64000bps, 56000bps
* and 48000bps. It passes the ITU tests.
*
* @note For the 56000bps and 48000bps bitrates, the lowest 1 or 2 bits
* respectively of each byte are ignored.
*/
#include "avcodec.h"
#include "mathops.h"
#include "get_bits.h"
#define PREV_SAMPLES_BUF_SIZE 1024
#define FREEZE_INTERVAL 128
typedef struct {
int16_t prev_samples[PREV_SAMPLES_BUF_SIZE]; ///< memory of past decoded samples
int prev_samples_pos; ///< the number of values in prev_samples
/**
* The band[0] and band[1] correspond respectively to the lower band and higher band.
*/
struct G722Band {
int16_t s_predictor; ///< predictor output value
int32_t s_zero; ///< previous output signal from zero predictor
int8_t part_reconst_mem[2]; ///< signs of previous partially reconstructed signals
int16_t prev_qtzd_reconst; ///< previous quantized reconstructed signal (internal value, using low_inv_quant4)
int16_t pole_mem[2]; ///< second-order pole section coefficient buffer
int32_t diff_mem[6]; ///< quantizer difference signal memory
int16_t zero_mem[6]; ///< Seventh-order zero section coefficient buffer
int16_t log_factor; ///< delayed 2-logarithmic quantizer factor
int16_t scale_factor; ///< delayed quantizer scale factor
} band[2];
struct TrellisNode {
struct G722Band state;
uint32_t ssd;
int path;
} *node_buf[2], **nodep_buf[2];
struct TrellisPath {
int value;
int prev;
} *paths[2];
} G722Context;
static const int8_t sign_lookup[2] = { -1, 1 };
static const int16_t inv_log2_table[32] = {
2048, 2093, 2139, 2186, 2233, 2282, 2332, 2383,
2435, 2489, 2543, 2599, 2656, 2714, 2774, 2834,
2896, 2960, 3025, 3091, 3158, 3228, 3298, 3371,
3444, 3520, 3597, 3676, 3756, 3838, 3922, 4008
};
static const int16_t high_log_factor_step[2] = { 798, -214 };
static const int16_t high_inv_quant[4] = { -926, -202, 926, 202 };
/**
* low_log_factor_step[index] == wl[rl42[index]]
*/
static const int16_t low_log_factor_step[16] = {
-60, 3042, 1198, 538, 334, 172, 58, -30,
3042, 1198, 538, 334, 172, 58, -30, -60
};
static const int16_t low_inv_quant4[16] = {
0, -2557, -1612, -1121, -786, -530, -323, -150,
2557, 1612, 1121, 786, 530, 323, 150, 0
};
static const int16_t low_inv_quant6[64] = {
-17, -17, -17, -17, -3101, -2738, -2376, -2088,
-1873, -1689, -1535, -1399, -1279, -1170, -1072, -982,
-899, -822, -750, -682, -618, -558, -501, -447,
-396, -347, -300, -254, -211, -170, -130, -91,
3101, 2738, 2376, 2088, 1873, 1689, 1535, 1399,
1279, 1170, 1072, 982, 899, 822, 750, 682,
618, 558, 501, 447, 396, 347, 300, 254,
211, 170, 130, 91, 54, 17, -54, -17
};
/**
* quadrature mirror filter (QMF) coefficients
*
* ITU-T G.722 Table 11
*/
static const int16_t qmf_coeffs[12] = {
3, -11, 12, 32, -210, 951, 3876, -805, 362, -156, 53, -11,
};
/**
* adaptive predictor
*
* @param cur_diff the dequantized and scaled delta calculated from the
* current codeword
*/
static void do_adaptive_prediction(struct G722Band *band, const int cur_diff)
{
int sg[2], limit, i, cur_qtzd_reconst;
const int cur_part_reconst = band->s_zero + cur_diff < 0;
sg[0] = sign_lookup[cur_part_reconst != band->part_reconst_mem[0]];
sg[1] = sign_lookup[cur_part_reconst == band->part_reconst_mem[1]];
band->part_reconst_mem[1] = band->part_reconst_mem[0];
band->part_reconst_mem[0] = cur_part_reconst;
band->pole_mem[1] = av_clip((sg[0] * av_clip(band->pole_mem[0], -8191, 8191) >> 5) +
(sg[1] << 7) + (band->pole_mem[1] * 127 >> 7), -12288, 12288);
limit = 15360 - band->pole_mem[1];
band->pole_mem[0] = av_clip(-192 * sg[0] + (band->pole_mem[0] * 255 >> 8), -limit, limit);
if (cur_diff) {
for (i = 0; i < 6; i++)
band->zero_mem[i] = ((band->zero_mem[i]*255) >> 8) +
((band->diff_mem[i]^cur_diff) < 0 ? -128 : 128);
} else
for (i = 0; i < 6; i++)
band->zero_mem[i] = (band->zero_mem[i]*255) >> 8;
for (i = 5; i > 0; i--)
band->diff_mem[i] = band->diff_mem[i-1];
band->diff_mem[0] = av_clip_int16(cur_diff << 1);
band->s_zero = 0;
for (i = 5; i >= 0; i--)
band->s_zero += (band->zero_mem[i]*band->diff_mem[i]) >> 15;
cur_qtzd_reconst = av_clip_int16((band->s_predictor + cur_diff) << 1);
band->s_predictor = av_clip_int16(band->s_zero +
(band->pole_mem[0] * cur_qtzd_reconst >> 15) +
(band->pole_mem[1] * band->prev_qtzd_reconst >> 15));
band->prev_qtzd_reconst = cur_qtzd_reconst;
}
static int inline linear_scale_factor(const int log_factor)
{
const int wd1 = inv_log2_table[(log_factor >> 6) & 31];
const int shift = log_factor >> 11;
return shift < 0 ? wd1 >> -shift : wd1 << shift;
}
static void update_low_predictor(struct G722Band *band, const int ilow)
{
do_adaptive_prediction(band,
band->scale_factor * low_inv_quant4[ilow] >> 10);
// quantizer adaptation
band->log_factor = av_clip((band->log_factor * 127 >> 7) +
low_log_factor_step[ilow], 0, 18432);
band->scale_factor = linear_scale_factor(band->log_factor - (8 << 11));
}
static void update_high_predictor(struct G722Band *band, const int dhigh,
const int ihigh)
{
do_adaptive_prediction(band, dhigh);
// quantizer adaptation
band->log_factor = av_clip((band->log_factor * 127 >> 7) +
high_log_factor_step[ihigh&1], 0, 22528);
band->scale_factor = linear_scale_factor(band->log_factor - (10 << 11));
}
static void apply_qmf(const int16_t *prev_samples, int *xout1, int *xout2)
{
int i;
*xout1 = 0;
*xout2 = 0;
for (i = 0; i < 12; i++) {
MAC16(*xout2, prev_samples[2*i ], qmf_coeffs[i ]);
MAC16(*xout1, prev_samples[2*i+1], qmf_coeffs[11-i]);
}
}
static av_cold int g722_init(AVCodecContext * avctx)
{
G722Context *c = avctx->priv_data;
if (avctx->channels != 1) {
av_log(avctx, AV_LOG_ERROR, "Only mono tracks are allowed.\n");
return AVERROR_INVALIDDATA;
}
avctx->sample_fmt = AV_SAMPLE_FMT_S16;
switch (avctx->bits_per_coded_sample) {
case 8:
case 7:
case 6:
break;
default:
av_log(avctx, AV_LOG_WARNING, "Unsupported bits_per_coded_sample [%d], "
"assuming 8\n",
avctx->bits_per_coded_sample);
case 0:
avctx->bits_per_coded_sample = 8;
break;
}
c->band[0].scale_factor = 8;
c->band[1].scale_factor = 2;
c->prev_samples_pos = 22;
if (avctx->lowres)
avctx->sample_rate /= 2;
if (avctx->trellis) {
int frontier = 1 << avctx->trellis;
int max_paths = frontier * FREEZE_INTERVAL;
int i;
for (i = 0; i < 2; i++) {
c->paths[i] = av_mallocz(max_paths * sizeof(**c->paths));
c->node_buf[i] = av_mallocz(2 * frontier * sizeof(**c->node_buf));
c->nodep_buf[i] = av_mallocz(2 * frontier * sizeof(**c->nodep_buf));
}
}
return 0;
}
static av_cold int g722_close(AVCodecContext *avctx)
{
G722Context *c = avctx->priv_data;
int i;
for (i = 0; i < 2; i++) {
av_freep(&c->paths[i]);
av_freep(&c->node_buf[i]);
av_freep(&c->nodep_buf[i]);
}
return 0;
}
#if CONFIG_ADPCM_G722_DECODER
static const int16_t low_inv_quant5[32] = {
-35, -35, -2919, -2195, -1765, -1458, -1219, -1023,
-858, -714, -587, -473, -370, -276, -190, -110,
2919, 2195, 1765, 1458, 1219, 1023, 858, 714,
587, 473, 370, 276, 190, 110, 35, -35
};
static const int16_t *low_inv_quants[3] = { low_inv_quant6, low_inv_quant5,
low_inv_quant4 };
static int g722_decode_frame(AVCodecContext *avctx, void *data,
int *data_size, AVPacket *avpkt)
{
G722Context *c = avctx->priv_data;
int16_t *out_buf = data;
int j, out_len = 0;
const int skip = 8 - avctx->bits_per_coded_sample;
const int16_t *quantizer_table = low_inv_quants[skip];
GetBitContext gb;
init_get_bits(&gb, avpkt->data, avpkt->size * 8);
for (j = 0; j < avpkt->size; j++) {
int ilow, ihigh, rlow;
ihigh = get_bits(&gb, 2);
ilow = get_bits(&gb, 6 - skip);
skip_bits(&gb, skip);
rlow = av_clip((c->band[0].scale_factor * quantizer_table[ilow] >> 10)
+ c->band[0].s_predictor, -16384, 16383);
update_low_predictor(&c->band[0], ilow >> (2 - skip));
if (!avctx->lowres) {
const int dhigh = c->band[1].scale_factor *
high_inv_quant[ihigh] >> 10;
const int rhigh = av_clip(dhigh + c->band[1].s_predictor,
-16384, 16383);
int xout1, xout2;
update_high_predictor(&c->band[1], dhigh, ihigh);
c->prev_samples[c->prev_samples_pos++] = rlow + rhigh;
c->prev_samples[c->prev_samples_pos++] = rlow - rhigh;
apply_qmf(c->prev_samples + c->prev_samples_pos - 24,
&xout1, &xout2);
out_buf[out_len++] = av_clip_int16(xout1 >> 12);
out_buf[out_len++] = av_clip_int16(xout2 >> 12);
if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) {
memmove(c->prev_samples,
c->prev_samples + c->prev_samples_pos - 22,
22 * sizeof(c->prev_samples[0]));
c->prev_samples_pos = 22;
}
} else
out_buf[out_len++] = rlow;
}
*data_size = out_len << 1;
return avpkt->size;
}
AVCodec adpcm_g722_decoder = {
.name = "g722",
.type = AVMEDIA_TYPE_AUDIO,
.id = CODEC_ID_ADPCM_G722,
.priv_data_size = sizeof(G722Context),
.init = g722_init,
.decode = g722_decode_frame,
.long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
.max_lowres = 1,
};
#endif
#if CONFIG_ADPCM_G722_ENCODER
static const int16_t low_quant[33] = {
35, 72, 110, 150, 190, 233, 276, 323,
370, 422, 473, 530, 587, 650, 714, 786,
858, 940, 1023, 1121, 1219, 1339, 1458, 1612,
1765, 1980, 2195, 2557, 2919
};
static inline void filter_samples(G722Context *c, const int16_t *samples,
int *xlow, int *xhigh)
{
int xout1, xout2;
c->prev_samples[c->prev_samples_pos++] = samples[0];
c->prev_samples[c->prev_samples_pos++] = samples[1];
apply_qmf(c->prev_samples + c->prev_samples_pos - 24, &xout1, &xout2);
*xlow = xout1 + xout2 >> 13;
*xhigh = xout1 - xout2 >> 13;
if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) {
memmove(c->prev_samples,
c->prev_samples + c->prev_samples_pos - 22,
22 * sizeof(c->prev_samples[0]));
c->prev_samples_pos = 22;
}
}
static inline int encode_high(const struct G722Band *state, int xhigh)
{
int diff = av_clip_int16(xhigh - state->s_predictor);
int pred = 141 * state->scale_factor >> 8;
/* = diff >= 0 ? (diff < pred) + 2 : diff >= -pred */
return ((diff ^ (diff >> (sizeof(diff)*8-1))) < pred) + 2*(diff >= 0);
}
static inline int encode_low(const struct G722Band* state, int xlow)
{
int diff = av_clip_int16(xlow - state->s_predictor);
/* = diff >= 0 ? diff : -(diff + 1) */
int limit = diff ^ (diff >> (sizeof(diff)*8-1));
int i = 0;
limit = limit + 1 << 10;
if (limit > low_quant[8] * state->scale_factor)
i = 9;
while (i < 29 && limit > low_quant[i] * state->scale_factor)
i++;
return (diff < 0 ? (i < 2 ? 63 : 33) : 61) - i;
}
static int g722_encode_trellis(AVCodecContext *avctx,
uint8_t *dst, int buf_size, void *data)
{
G722Context *c = avctx->priv_data;
const int16_t *samples = data;
int i, j, k;
int frontier = 1 << avctx->trellis;
struct TrellisNode **nodes[2];
struct TrellisNode **nodes_next[2];
int pathn[2] = {0, 0}, froze = -1;
struct TrellisPath *p[2];
for (i = 0; i < 2; i++) {
nodes[i] = c->nodep_buf[i];
nodes_next[i] = c->nodep_buf[i] + frontier;
memset(c->nodep_buf[i], 0, 2 * frontier * sizeof(*c->nodep_buf));
nodes[i][0] = c->node_buf[i] + frontier;
nodes[i][0]->ssd = 0;
nodes[i][0]->path = 0;
nodes[i][0]->state = c->band[i];
}
for (i = 0; i < buf_size >> 1; i++) {
int xlow, xhigh;
struct TrellisNode *next[2];
int heap_pos[2] = {0, 0};
for (j = 0; j < 2; j++) {
next[j] = c->node_buf[j] + frontier*(i & 1);
memset(nodes_next[j], 0, frontier * sizeof(**nodes_next));
}
filter_samples(c, &samples[2*i], &xlow, &xhigh);
for (j = 0; j < frontier && nodes[0][j]; j++) {
/* Only k >> 2 affects the future adaptive state, therefore testing
* small steps that don't change k >> 2 is useless, the orignal
* value from encode_low is better than them. Since we step k
* in steps of 4, make sure range is a multiple of 4, so that
* we don't miss the original value from encode_low. */
int range = j < frontier/2 ? 4 : 0;
struct TrellisNode *cur_node = nodes[0][j];
int ilow = encode_low(&cur_node->state, xlow);
for (k = ilow - range; k <= ilow + range && k <= 63; k += 4) {
int decoded, dec_diff, pos;
uint32_t ssd;
struct TrellisNode* node;
if (k < 0)
continue;
decoded = av_clip((cur_node->state.scale_factor *
low_inv_quant6[k] >> 10)
+ cur_node->state.s_predictor, -16384, 16383);
dec_diff = xlow - decoded;
#define STORE_NODE(index, UPDATE, VALUE)\
ssd = cur_node->ssd + dec_diff*dec_diff;\
/* Check for wraparound. Using 64 bit ssd counters would \
* be simpler, but is slower on x86 32 bit. */\
if (ssd < cur_node->ssd)\
continue;\
if (heap_pos[index] < frontier) {\
pos = heap_pos[index]++;\
assert(pathn[index] < FREEZE_INTERVAL * frontier);\
node = nodes_next[index][pos] = next[index]++;\
node->path = pathn[index]++;\
} else {\
/* Try to replace one of the leaf nodes with the new \
* one, but not always testing the same leaf position */\
pos = (frontier>>1) + (heap_pos[index] & ((frontier>>1) - 1));\
if (ssd >= nodes_next[index][pos]->ssd)\
continue;\
heap_pos[index]++;\
node = nodes_next[index][pos];\
}\
node->ssd = ssd;\
node->state = cur_node->state;\
UPDATE;\
c->paths[index][node->path].value = VALUE;\
c->paths[index][node->path].prev = cur_node->path;\
/* Sift the newly inserted node up in the heap to restore \
* the heap property */\
while (pos > 0) {\
int parent = (pos - 1) >> 1;\
if (nodes_next[index][parent]->ssd <= ssd)\
break;\
FFSWAP(struct TrellisNode*, nodes_next[index][parent],\
nodes_next[index][pos]);\
pos = parent;\
}
STORE_NODE(0, update_low_predictor(&node->state, k >> 2), k);
}
}
for (j = 0; j < frontier && nodes[1][j]; j++) {
int ihigh;
struct TrellisNode *cur_node = nodes[1][j];
/* We don't try to get any initial guess for ihigh via
* encode_high - since there's only 4 possible values, test
* them all. Testing all of these gives a much, much larger
* gain than testing a larger range around ilow. */
for (ihigh = 0; ihigh < 4; ihigh++) {
int dhigh, decoded, dec_diff, pos;
uint32_t ssd;
struct TrellisNode* node;
dhigh = cur_node->state.scale_factor *
high_inv_quant[ihigh] >> 10;
decoded = av_clip(dhigh + cur_node->state.s_predictor,
-16384, 16383);
dec_diff = xhigh - decoded;
STORE_NODE(1, update_high_predictor(&node->state, dhigh, ihigh), ihigh);
}
}
for (j = 0; j < 2; j++) {
FFSWAP(struct TrellisNode**, nodes[j], nodes_next[j]);
if (nodes[j][0]->ssd > (1 << 16)) {
for (k = 1; k < frontier && nodes[j][k]; k++)
nodes[j][k]->ssd -= nodes[j][0]->ssd;
nodes[j][0]->ssd = 0;
}
}
if (i == froze + FREEZE_INTERVAL) {
p[0] = &c->paths[0][nodes[0][0]->path];
p[1] = &c->paths[1][nodes[1][0]->path];
for (j = i; j > froze; j--) {
dst[j] = p[1]->value << 6 | p[0]->value;
p[0] = &c->paths[0][p[0]->prev];
p[1] = &c->paths[1][p[1]->prev];
}
froze = i;
pathn[0] = pathn[1] = 0;
memset(nodes[0] + 1, 0, (frontier - 1)*sizeof(**nodes));
memset(nodes[1] + 1, 0, (frontier - 1)*sizeof(**nodes));
}
}
p[0] = &c->paths[0][nodes[0][0]->path];
p[1] = &c->paths[1][nodes[1][0]->path];
for (j = i; j > froze; j--) {
dst[j] = p[1]->value << 6 | p[0]->value;
p[0] = &c->paths[0][p[0]->prev];
p[1] = &c->paths[1][p[1]->prev];
}
c->band[0] = nodes[0][0]->state;
c->band[1] = nodes[1][0]->state;
return i;
}
static int g722_encode_frame(AVCodecContext *avctx,
uint8_t *dst, int buf_size, void *data)
{
G722Context *c = avctx->priv_data;
const int16_t *samples = data;
int i;
if (avctx->trellis)
return g722_encode_trellis(avctx, dst, buf_size, data);
for (i = 0; i < buf_size >> 1; i++) {
int xlow, xhigh, ihigh, ilow;
filter_samples(c, &samples[2*i], &xlow, &xhigh);
ihigh = encode_high(&c->band[1], xhigh);
ilow = encode_low(&c->band[0], xlow);
update_high_predictor(&c->band[1], c->band[1].scale_factor *
high_inv_quant[ihigh] >> 10, ihigh);
update_low_predictor(&c->band[0], ilow >> 2);
*dst++ = ihigh << 6 | ilow;
}
return i;
}
AVCodec adpcm_g722_encoder = {
.name = "g722",
.type = AVMEDIA_TYPE_AUDIO,
.id = CODEC_ID_ADPCM_G722,
.priv_data_size = sizeof(G722Context),
.init = g722_init,
.close = g722_close,
.encode = g722_encode_frame,
.long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
.sample_fmts = (enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
};
#endif
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