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FFmpeg/libavcodec/g722enc.c

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/*
* 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 Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* G.722 ADPCM audio encoder
*/
#include "avcodec.h"
#include "internal.h"
#include "g722.h"
#include "libavutil/common.h"
#define FREEZE_INTERVAL 128
/* This is an arbitrary value. Allowing insanely large values leads to strange
problems, so we limit it to a reasonable value */
#define MAX_FRAME_SIZE 32768
/* We clip the value of avctx->trellis to prevent data type overflows and
undefined behavior. Using larger values is insanely slow anyway. */
#define MIN_TRELLIS 0
#define MAX_TRELLIS 16
static av_cold int g722_encode_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;
}
static av_cold int g722_encode_init(AVCodecContext * avctx)
{
G722Context *c = avctx->priv_data;
int ret;
if (avctx->channels != 1) {
av_log(avctx, AV_LOG_ERROR, "Only mono tracks are allowed.\n");
return AVERROR_INVALIDDATA;
}
c->band[0].scale_factor = 8;
c->band[1].scale_factor = 2;
c->prev_samples_pos = 22;
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));
if (!c->paths[i] || !c->node_buf[i] || !c->nodep_buf[i]) {
ret = AVERROR(ENOMEM);
goto error;
}
}
}
if (avctx->frame_size) {
/* validate frame size */
if (avctx->frame_size & 1 || avctx->frame_size > MAX_FRAME_SIZE) {
int new_frame_size;
if (avctx->frame_size == 1)
new_frame_size = 2;
else if (avctx->frame_size > MAX_FRAME_SIZE)
new_frame_size = MAX_FRAME_SIZE;
else
new_frame_size = avctx->frame_size - 1;
av_log(avctx, AV_LOG_WARNING, "Requested frame size is not "
"allowed. Using %d instead of %d\n", new_frame_size,
avctx->frame_size);
avctx->frame_size = new_frame_size;
}
} else {
/* This is arbitrary. We use 320 because it's 20ms @ 16kHz, which is
a common packet size for VoIP applications */
avctx->frame_size = 320;
}
avctx->delay = 22;
if (avctx->trellis) {
/* validate trellis */
if (avctx->trellis < MIN_TRELLIS || avctx->trellis > MAX_TRELLIS) {
int new_trellis = av_clip(avctx->trellis, MIN_TRELLIS, MAX_TRELLIS);
av_log(avctx, AV_LOG_WARNING, "Requested trellis value is not "
"allowed. Using %d instead of %d\n", new_trellis,
avctx->trellis);
avctx->trellis = new_trellis;
}
}
return 0;
error:
g722_encode_close(avctx);
return ret;
}
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];
ff_g722_apply_qmf(c->prev_samples + c->prev_samples_pos - 24, &xout1, &xout2);
*xlow = xout1 + xout2 >> 14;
*xhigh = xout1 - xout2 >> 14;
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 void g722_encode_trellis(G722Context *c, int trellis,
uint8_t *dst, int nb_samples,
const int16_t *samples)
{
int i, j, k;
int frontier = 1 << 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[i]));
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 < nb_samples >> 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 original
* 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 *
ff_g722_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, ff_g722_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 *
ff_g722_high_inv_quant[ihigh] >> 10;
decoded = av_clip(dhigh + cur_node->state.s_predictor,
-16384, 16383);
dec_diff = xhigh - decoded;
STORE_NODE(1, ff_g722_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;
}
static av_always_inline void encode_byte(G722Context *c, uint8_t *dst,
const int16_t *samples)
{
int xlow, xhigh, ilow, ihigh;
filter_samples(c, samples, &xlow, &xhigh);
ihigh = encode_high(&c->band[1], xhigh);
ilow = encode_low (&c->band[0], xlow);
ff_g722_update_high_predictor(&c->band[1], c->band[1].scale_factor *
ff_g722_high_inv_quant[ihigh] >> 10, ihigh);
ff_g722_update_low_predictor(&c->band[0], ilow >> 2);
*dst = ihigh << 6 | ilow;
}
static void g722_encode_no_trellis(G722Context *c,
uint8_t *dst, int nb_samples,
const int16_t *samples)
{
int i;
for (i = 0; i < nb_samples; i += 2)
encode_byte(c, dst++, &samples[i]);
}
static int g722_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
const AVFrame *frame, int *got_packet_ptr)
{
G722Context *c = avctx->priv_data;
const int16_t *samples = (const int16_t *)frame->data[0];
int nb_samples, out_size, ret;
out_size = (frame->nb_samples + 1) / 2;
if ((ret = ff_alloc_packet(avpkt, out_size))) {
av_log(avctx, AV_LOG_ERROR, "Error getting output packet\n");
return ret;
}
nb_samples = frame->nb_samples - (frame->nb_samples & 1);
if (avctx->trellis)
g722_encode_trellis(c, avctx->trellis, avpkt->data, nb_samples, samples);
else
g722_encode_no_trellis(c, avpkt->data, nb_samples, samples);
/* handle last frame with odd frame_size */
if (nb_samples < frame->nb_samples) {
int16_t last_samples[2] = { samples[nb_samples], samples[nb_samples] };
encode_byte(c, &avpkt->data[nb_samples >> 1], last_samples);
}
if (frame->pts != AV_NOPTS_VALUE)
avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->delay);
*got_packet_ptr = 1;
return 0;
}
AVCodec ff_adpcm_g722_encoder = {
.name = "g722",
.long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_ADPCM_G722,
.priv_data_size = sizeof(G722Context),
.init = g722_encode_init,
.close = g722_encode_close,
.encode2 = g722_encode_frame,
.capabilities = CODEC_CAP_SMALL_LAST_FRAME,
.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
AV_SAMPLE_FMT_NONE },
};
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