diff options
Diffstat (limited to 'ffmpeg/libavformat/amr.c')
| -rw-r--r-- | ffmpeg/libavformat/amr.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/ffmpeg/libavformat/amr.c b/ffmpeg/libavformat/amr.c new file mode 100644 index 0000000..07ab1ba --- /dev/null +++ b/ffmpeg/libavformat/amr.c @@ -0,0 +1,182 @@ +/* + * 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/avassert.h" +#include "libavutil/channel_layout.h" +#include "avformat.h" +#include "internal.h" + +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); + avio_flush(s->pb); + 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); + + if (url_feof(s->pb)) { + return AVERROR(EIO); + } + + // FIXME this is wrong, this should rather be in a AVParset + 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]; + } else { + av_assert0(0); + } + + if (!size || av_new_packet(pkt, size)) + return AVERROR(EIO); + + /* Both AMR formats have 50 frames per second */ + s->streams[0]->codec->bit_rate = size*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_free_packet(pkt); + return AVERROR(EIO); + } + + return 0; +} + +#if CONFIG_AMR_DEMUXER +AVInputFormat ff_amr_demuxer = { + .name = "amr", + .long_name = NULL_IF_CONFIG_SMALL("3GPP AMR"), + .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, +}; +#endif |