mirror of
https://git.videolan.org/git/ffmpeg.git
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169 lines
4.4 KiB
C
169 lines
4.4 KiB
C
/*
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* G.729 bit format muxer and demuxer
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* Copyright (c) 2007-2008 Vladimir Voroshilov
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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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#include "avformat.h"
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#include "internal.h"
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#include "libavcodec/get_bits.h"
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#include "libavcodec/put_bits.h"
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#define MAX_FRAME_SIZE 10
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#define SYNC_WORD 0x6b21
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#define BIT_0 0x7f
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#define BIT_1 0x81
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#if CONFIG_BIT_DEMUXER
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static int probe(const AVProbeData *p)
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{
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int i = 0, j, valid = 0;
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while (2 * i + 3 < p->buf_size){
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if (AV_RL16(&p->buf[2 * i++]) != SYNC_WORD)
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return 0;
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j = AV_RL16(&p->buf[2 * i++]);
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if (j != 0 && j != 0x10 && j != 0x40 && j != 0x50 && j != 0x76)
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return 0;
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if (j)
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valid++;
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i += j;
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}
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if (valid > 10)
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return AVPROBE_SCORE_MAX;
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if (valid > 2)
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return AVPROBE_SCORE_EXTENSION - 1;
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return 0;
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}
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static int read_header(AVFormatContext *s)
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{
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AVStream* st;
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st=avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
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st->codecpar->codec_id=AV_CODEC_ID_G729;
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st->codecpar->sample_rate=8000;
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st->codecpar->block_align = 16;
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st->codecpar->channels=1;
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avpriv_set_pts_info(st, 64, 1, 100);
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return 0;
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}
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static int read_packet(AVFormatContext *s,
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AVPacket *pkt)
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{
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AVIOContext *pb = s->pb;
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PutBitContext pbo;
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uint16_t buf[8 * MAX_FRAME_SIZE + 2];
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int packet_size;
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uint16_t* src=buf;
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int i, j, ret;
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int64_t pos= avio_tell(pb);
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if(avio_feof(pb))
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return AVERROR_EOF;
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avio_rl16(pb); // sync word
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packet_size = avio_rl16(pb) / 8;
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if(packet_size > MAX_FRAME_SIZE)
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return AVERROR_INVALIDDATA;
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ret = avio_read(pb, (uint8_t*)buf, (8 * packet_size) * sizeof(uint16_t));
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if(ret<0)
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return ret;
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if(ret != 8 * packet_size * sizeof(uint16_t))
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return AVERROR(EIO);
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if (av_new_packet(pkt, packet_size) < 0)
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return AVERROR(ENOMEM);
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init_put_bits(&pbo, pkt->data, packet_size);
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for(j=0; j < packet_size; j++)
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for(i=0; i<8;i++)
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put_bits(&pbo,1, AV_RL16(src++) == BIT_1 ? 1 : 0);
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flush_put_bits(&pbo);
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pkt->duration=1;
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pkt->pos = pos;
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return 0;
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}
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AVInputFormat ff_bit_demuxer = {
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.name = "bit",
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.long_name = NULL_IF_CONFIG_SMALL("G.729 BIT file format"),
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.read_probe = probe,
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.read_header = read_header,
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.read_packet = read_packet,
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.extensions = "bit",
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};
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#endif
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#if CONFIG_BIT_MUXER
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static int write_header(AVFormatContext *s)
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{
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AVCodecParameters *par = s->streams[0]->codecpar;
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if ((par->codec_id != AV_CODEC_ID_G729) || par->channels != 1) {
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av_log(s, AV_LOG_ERROR,
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"only codec g729 with 1 channel is supported by this format\n");
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return AVERROR(EINVAL);
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}
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par->bits_per_coded_sample = 16;
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par->block_align = (par->bits_per_coded_sample * par->channels) >> 3;
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return 0;
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}
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static int write_packet(AVFormatContext *s, AVPacket *pkt)
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{
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AVIOContext *pb = s->pb;
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GetBitContext gb;
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int i;
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if (pkt->size != 10)
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return AVERROR(EINVAL);
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avio_wl16(pb, SYNC_WORD);
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avio_wl16(pb, 8 * pkt->size);
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init_get_bits(&gb, pkt->data, 8 * pkt->size);
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for (i = 0; i < 8 * pkt->size; i++)
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avio_wl16(pb, get_bits1(&gb) ? BIT_1 : BIT_0);
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return 0;
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}
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AVOutputFormat ff_bit_muxer = {
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.name = "bit",
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.long_name = NULL_IF_CONFIG_SMALL("G.729 BIT file format"),
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.mime_type = "audio/bit",
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.extensions = "bit",
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.audio_codec = AV_CODEC_ID_G729,
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.video_codec = AV_CODEC_ID_NONE,
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.write_header = write_header,
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.write_packet = write_packet,
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};
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#endif
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