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Diffstat (limited to 'libavformat/bit.c')
| -rw-r--r-- | libavformat/bit.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/libavformat/bit.c b/libavformat/bit.c new file mode 100644 index 0000000000..b0931f429b --- /dev/null +++ b/libavformat/bit.c @@ -0,0 +1,156 @@ +/* + * G.729 bit format muxer and demuxer + * Copyright (c) 2007-2008 Vladimir Voroshilov + * + * 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 + */ +#include "avformat.h" +#include "internal.h" +#include "libavcodec/get_bits.h" +#include "libavcodec/put_bits.h" + +#define MAX_FRAME_SIZE 10 + +#define SYNC_WORD 0x6b21 +#define BIT_0 0x7f +#define BIT_1 0x81 + +static int probe(AVProbeData *p) +{ + int i, j; + + if(p->buf_size < 0x40) + return 0; + + for(i=0; i+3<p->buf_size && i< 10*0x50; ){ + if(AV_RL16(&p->buf[0]) != SYNC_WORD) + return 0; + j=AV_RL16(&p->buf[2]); + if(j!=0x40 && j!=0x50) + return 0; + i+=j; + } + return AVPROBE_SCORE_MAX/2; +} + +static int read_header(AVFormatContext *s) +{ + AVStream* st; + + st=avformat_new_stream(s, NULL); + if (!st) + return AVERROR(ENOMEM); + + st->codec->codec_type = AVMEDIA_TYPE_AUDIO; + st->codec->codec_id=CODEC_ID_G729; + st->codec->sample_rate=8000; + st->codec->block_align = 16; + st->codec->channels=1; + + avpriv_set_pts_info(st, 64, 1, 100); + return 0; +} + +static int read_packet(AVFormatContext *s, + AVPacket *pkt) +{ + AVIOContext *pb = s->pb; + PutBitContext pbo; + uint16_t buf[8 * MAX_FRAME_SIZE + 2]; + int packet_size; + uint16_t* src=buf; + int i, j, ret; + int64_t pos= avio_tell(pb); + + if(url_feof(pb)) + return AVERROR_EOF; + + avio_rl16(pb); // sync word + packet_size = avio_rl16(pb) / 8; + if(packet_size > MAX_FRAME_SIZE) + return AVERROR_INVALIDDATA; + + ret = avio_read(pb, (uint8_t*)buf, (8 * packet_size) * sizeof(uint16_t)); + if(ret<0) + return ret; + if(ret != 8 * packet_size * sizeof(uint16_t)) + return AVERROR(EIO); + + av_new_packet(pkt, packet_size); + + init_put_bits(&pbo, pkt->data, packet_size); + for(j=0; j < packet_size; j++) + for(i=0; i<8;i++) + put_bits(&pbo,1, AV_RL16(src++) == BIT_1 ? 1 : 0); + + flush_put_bits(&pbo); + + pkt->duration=1; + pkt->pos = pos; + return 0; +} + +AVInputFormat ff_bit_demuxer = { + .name = "bit", + .long_name = NULL_IF_CONFIG_SMALL("G.729 BIT file format"), + .read_probe = probe, + .read_header = read_header, + .read_packet = read_packet, + .extensions = "bit", +}; + +#if CONFIG_MUXERS +static int write_header(AVFormatContext *s) +{ + AVCodecContext *enc = s->streams[0]->codec; + + enc->codec_id = CODEC_ID_G729; + enc->channels = 1; + enc->bits_per_coded_sample = 16; + enc->block_align = (enc->bits_per_coded_sample * enc->channels) >> 3; + + return 0; +} + +static int write_packet(AVFormatContext *s, AVPacket *pkt) +{ + AVIOContext *pb = s->pb; + GetBitContext gb; + int i; + + avio_wl16(pb, SYNC_WORD); + avio_wl16(pb, 8 * 10); + + init_get_bits(&gb, pkt->data, 8*10); + for(i=0; i< 8 * 10; i++) + avio_wl16(pb, get_bits1(&gb) ? BIT_1 : BIT_0); + avio_flush(pb); + + return 0; +} + +AVOutputFormat ff_bit_muxer = { + .name = "bit", + .long_name = NULL_IF_CONFIG_SMALL("G.729 BIT file format"), + .mime_type = "audio/bit", + .extensions = "bit", + .audio_codec = CODEC_ID_G729, + .video_codec = CODEC_ID_NONE, + .write_header = write_header, + .write_packet = write_packet, +}; +#endif |