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/*
* Copyright (c) 2021 Paul B Mahol
*
* 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
* AMR audio parser
*
* Splits packets into individual blocks.
*/
#include "libavutil/channel_layout.h"
#include "libavutil/intreadwrite.h"
#include "parser.h"
static const uint8_t amrnb_packed_size[16] = {
13, 14, 16, 18, 20, 21, 27, 32, 6, 1, 1, 1, 1, 1, 1, 1
};
static const uint8_t amrwb_packed_size[16] = {
18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 1, 1, 1, 1, 1, 1
};
typedef struct AMRParseContext {
ParseContext pc;
uint64_t cumulated_size;
uint64_t block_count;
int current_channel;
int remaining;
} AMRParseContext;
static av_cold int amr_parse_init(AVCodecParserContext *s1)
{
AMRParseContext *s = s1->priv_data;
s->remaining = -1;
return 0;
}
static int amr_parse(AVCodecParserContext *s1,
AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
AMRParseContext *s = s1->priv_data;
ParseContext *pc = &s->pc;
int next = END_NOT_FOUND;
*poutbuf_size = 0;
*poutbuf = NULL;
if (!avctx->ch_layout.nb_channels) {
av_channel_layout_uninit(&avctx->ch_layout);
avctx->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
}
if (s1->flags & PARSER_FLAG_COMPLETE_FRAMES) {
next = buf_size;
} else {
int ch, offset = 0;
for (ch = s->current_channel; ch < avctx->ch_layout.nb_channels; ch++) {
if (s->remaining >= 0) {
next = s->remaining;
} else {
int mode = (buf[offset] >> 3) & 0x0F;
if (avctx->codec_id == AV_CODEC_ID_AMR_NB) {
next = amrnb_packed_size[mode];
} else if (avctx->codec_id == AV_CODEC_ID_AMR_WB) {
next = amrwb_packed_size[mode];
}
}
offset += next;
if (offset >= buf_size) {
s->remaining = offset - buf_size;
next = END_NOT_FOUND;
break;
} else {
s->remaining = -1;
}
}
s->current_channel = ch % avctx->ch_layout.nb_channels;
if (s->remaining < 0)
next = offset;
if (next != END_NOT_FOUND) {
if (s->cumulated_size < UINT64_MAX - next) {
s->cumulated_size += next;
/* Both AMR formats have 50 frames per second */
avctx->bit_rate = s->cumulated_size / ++s->block_count * 8 * 50;
}
}
if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size;
}
}
s1->duration = avctx->codec_id == AV_CODEC_ID_AMR_NB ? 160 : 320;
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
}
const AVCodecParser ff_amr_parser = {
.codec_ids = { AV_CODEC_ID_AMR_NB, AV_CODEC_ID_AMR_WB },
.priv_data_size = sizeof(AMRParseContext),
.parser_init = amr_parse_init,
.parser_parse = amr_parse,
.parser_close = ff_parse_close,
};
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