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/*
* amr file format
* Copyright (c) 2001 ffmpeg project
*
* 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
*/
/*
Write and read amr data according to RFC3267, http://www.ietf.org/rfc/rfc3267.txt?number=3267
Only mono files are supported.
*/
#include "libavutil/channel_layout.h"
#include "avformat.h"
#include "internal.h"
typedef struct {
uint64_t cumulated_size;
uint64_t block_count;
} AMRContext;
static const char AMR_header[] = "#!AMR\n";
static const char AMRWB_header[] = "#!AMR-WB\n";
#if CONFIG_AMR_MUXER
static int amr_write_header(AVFormatContext *s)
{
AVIOContext *pb = s->pb;
AVCodecContext *enc = s->streams[0]->codec;
s->priv_data = NULL;
if (enc->codec_id == AV_CODEC_ID_AMR_NB) {
avio_write(pb, AMR_header, sizeof(AMR_header) - 1); /* magic number */
} else if (enc->codec_id == AV_CODEC_ID_AMR_WB) {
avio_write(pb, AMRWB_header, sizeof(AMRWB_header) - 1); /* magic number */
} else {
return -1;
}
avio_flush(pb);
return 0;
}
static int amr_write_packet(AVFormatContext *s, AVPacket *pkt)
{
avio_write(s->pb, pkt->data, pkt->size);
return 0;
}
#endif /* CONFIG_AMR_MUXER */
static int amr_probe(AVProbeData *p)
{
// Only check for "#!AMR" which could be amr-wb, amr-nb.
// This will also trigger multichannel files: "#!AMR_MC1.0\n" and
// "#!AMR-WB_MC1.0\n" (not supported)
if (!memcmp(p->buf, AMR_header, 5))
return AVPROBE_SCORE_MAX;
else
return 0;
}
/* amr input */
static int amr_read_header(AVFormatContext *s)
{
AVIOContext *pb = s->pb;
AVStream *st;
uint8_t header[9];
avio_read(pb, header, 6);
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
if (memcmp(header, AMR_header, 6)) {
avio_read(pb, header + 6, 3);
if (memcmp(header, AMRWB_header, 9)) {
return -1;
}
st->codec->codec_tag = MKTAG('s', 'a', 'w', 'b');
st->codec->codec_id = AV_CODEC_ID_AMR_WB;
st->codec->sample_rate = 16000;
} else {
st->codec->codec_tag = MKTAG('s', 'a', 'm', 'r');
st->codec->codec_id = AV_CODEC_ID_AMR_NB;
st->codec->sample_rate = 8000;
}
st->codec->channels = 1;
st->codec->channel_layout = AV_CH_LAYOUT_MONO;
st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
return 0;
}
static int amr_read_packet(AVFormatContext *s, AVPacket *pkt)
{
AVCodecContext *enc = s->streams[0]->codec;
int read, size = 0, toc, mode;
int64_t pos = avio_tell(s->pb);
AMRContext *amr = s->priv_data;
if (avio_feof(s->pb)) {
return AVERROR(EIO);
}
// FIXME this is wrong, this should rather be in a AVParser
toc = avio_r8(s->pb);
mode = (toc >> 3) & 0x0F;
if (enc->codec_id == AV_CODEC_ID_AMR_NB) {
static const uint8_t packed_size[16] = {
12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0
};
size = packed_size[mode] + 1;
} else if (enc->codec_id == AV_CODEC_ID_AMR_WB) {
static const uint8_t packed_size[16] = {
18, 24, 33, 37, 41, 47, 51, 59, 61, 6, 6, 0, 0, 0, 1, 1
};
size = packed_size[mode];
}
if (!size || av_new_packet(pkt, size))
return AVERROR(EIO);
if (amr->cumulated_size < UINT64_MAX - size) {
amr->cumulated_size += size;
/* Both AMR formats have 50 frames per second */
s->streams[0]->codec->bit_rate = amr->cumulated_size / ++amr->block_count * 8 * 50;
}
pkt->stream_index = 0;
pkt->pos = pos;
pkt->data[0] = toc;
pkt->duration = enc->codec_id == AV_CODEC_ID_AMR_NB ? 160 : 320;
read = avio_read(s->pb, pkt->data + 1, size - 1);
if (read != size - 1) {
av_packet_unref(pkt);
return AVERROR(EIO);
}
return 0;
}
#if CONFIG_AMR_DEMUXER
AVInputFormat ff_amr_demuxer = {
.name = "amr",
.long_name = NULL_IF_CONFIG_SMALL("3GPP AMR"),
.priv_data_size = sizeof(AMRContext),
.read_probe = amr_probe,
.read_header = amr_read_header,
.read_packet = amr_read_packet,
.flags = AVFMT_GENERIC_INDEX,
};
#endif
#if CONFIG_AMR_MUXER
AVOutputFormat ff_amr_muxer = {
.name = "amr",
.long_name = NULL_IF_CONFIG_SMALL("3GPP AMR"),
.mime_type = "audio/amr",
.extensions = "amr",
.audio_codec = AV_CODEC_ID_AMR_NB,
.video_codec = AV_CODEC_ID_NONE,
.write_header = amr_write_header,
.write_packet = amr_write_packet,
.flags = AVFMT_NOTIMESTAMPS,
};
#endif
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