mirror of https://git.ffmpeg.org/ffmpeg.git
132 lines
3.8 KiB
C
132 lines
3.8 KiB
C
/*
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* Copyright (c) 2021 Paul B Mahol
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* AMR audio parser
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*
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* Splits packets into individual blocks.
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*/
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#include "libavutil/channel_layout.h"
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#include "libavutil/intreadwrite.h"
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#include "parser.h"
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static const uint8_t amrnb_packed_size[16] = {
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13, 14, 16, 18, 20, 21, 27, 32, 6, 1, 1, 1, 1, 1, 1, 1
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};
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static const uint8_t amrwb_packed_size[16] = {
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18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 1, 1, 1, 1, 1, 1
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};
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typedef struct AMRParseContext {
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ParseContext pc;
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uint64_t cumulated_size;
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uint64_t block_count;
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int current_channel;
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int remaining;
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} AMRParseContext;
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static av_cold int amr_parse_init(AVCodecParserContext *s1)
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{
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AMRParseContext *s = s1->priv_data;
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s->remaining = -1;
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return 0;
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}
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static int amr_parse(AVCodecParserContext *s1,
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AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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AMRParseContext *s = s1->priv_data;
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ParseContext *pc = &s->pc;
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int next = END_NOT_FOUND;
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*poutbuf_size = 0;
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*poutbuf = NULL;
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if (!avctx->channels) {
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avctx->channels = 1;
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avctx->channel_layout = AV_CH_LAYOUT_MONO;
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}
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if (s1->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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next = buf_size;
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} else {
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int ch, offset = 0;
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for (ch = s->current_channel; ch < avctx->channels; ch++) {
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if (s->remaining >= 0) {
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next = s->remaining;
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} else {
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int mode = (buf[offset] >> 3) & 0x0F;
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if (avctx->codec_id == AV_CODEC_ID_AMR_NB) {
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next = amrnb_packed_size[mode];
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} else if (avctx->codec_id == AV_CODEC_ID_AMR_WB) {
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next = amrwb_packed_size[mode];
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}
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}
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offset += next;
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if (offset >= buf_size) {
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s->remaining = offset - buf_size;
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next = END_NOT_FOUND;
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break;
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} else {
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s->remaining = -1;
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}
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}
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s->current_channel = ch % avctx->channels;
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if (s->remaining < 0)
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next = offset;
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if (next != END_NOT_FOUND) {
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if (s->cumulated_size < UINT64_MAX - next) {
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s->cumulated_size += next;
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/* Both AMR formats have 50 frames per second */
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avctx->bit_rate = s->cumulated_size / ++s->block_count * 8 * 50;
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}
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}
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if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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}
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s1->duration = avctx->codec_id == AV_CODEC_ID_AMR_NB ? 160 : 320;
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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const AVCodecParser ff_amr_parser = {
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.codec_ids = { AV_CODEC_ID_AMR_NB, AV_CODEC_ID_AMR_WB },
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.priv_data_size = sizeof(AMRParseContext),
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.parser_init = amr_parse_init,
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.parser_parse = amr_parse,
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.parser_close = ff_parse_close,
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};
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