mirror of https://github.com/FFmpeg/FFmpeg.git
Originally committed as revision 6667 to svn://svn.ffmpeg.org/ffmpeg/trunkpull/126/head
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/*
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* mtv demuxer |
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* Copyright (c) 2006 Reynaldo H. Verdejo Pinochet |
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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 mtv.c |
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* MTV demuxer. |
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*/ |
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#include "avformat.h" |
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#include "bswap.h" |
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#define MTV_ASUBCHUNK_DATA_SIZE 500 |
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#define MTV_HEADER_SIZE 512 |
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#define MTV_AUDIO_PADDING_SIZE 12 |
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#define AUDIO_SAMPLING_RATE 44100 |
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#define VIDEO_SID 0 |
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#define AUDIO_SID 1 |
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typedef struct MTVDemuxContext { |
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unsigned int file_size; ///< filesize, not always right
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unsigned int segments; ///< number of 512 byte segments
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unsigned int audio_identifier; ///< 'MP3' on all files I have seen
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unsigned int audio_br; ///< bitrate of audio chanel (mp3)
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unsigned int img_colorfmt; ///< frame colorfmt rgb 565/555
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unsigned int img_bpp; ///< frame bits per pixel
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unsigned int img_width; //
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unsigned int img_height; //
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unsigned int img_segment_size; ///< size of image segment
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unsigned int video_fps; //
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unsigned int audio_subsegments; ///< audio subsegments on one segment
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uint8_t audio_packet_count; |
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} MTVDemuxContext; |
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static int mtv_probe(AVProbeData *p) |
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{ |
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if(p->buf_size < 3) |
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return 0; |
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/* Magic is 'AMV' */ |
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if(*(p->buf) != 'A' || *(p->buf+1) != 'M' || *(p->buf+2) != 'V') |
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return 0; |
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return AVPROBE_SCORE_MAX; |
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} |
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static int mtv_read_header(AVFormatContext *s, AVFormatParameters *ap) |
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{ |
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MTVDemuxContext *mtv = s->priv_data; |
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ByteIOContext *pb = &s->pb; |
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AVStream *st; |
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url_fskip(pb, 3); |
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mtv->file_size = get_le32(pb); |
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mtv->segments = get_le32(pb); |
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url_fskip(pb, 32); |
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mtv->audio_identifier = get_le24(pb); |
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mtv->audio_br = get_le16(pb); |
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mtv->img_colorfmt = get_le24(pb); |
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mtv->img_bpp = get_byte(pb); |
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mtv->img_width = get_le16(pb); |
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mtv->img_height = get_le16(pb); |
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mtv->img_segment_size = get_le16(pb); |
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url_fskip(pb, 4); |
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mtv->audio_subsegments = get_le16(pb); |
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mtv->video_fps = (mtv->audio_br / 4) / mtv->audio_subsegments; |
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/* FIXME Add sanity check here */ |
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/* first packet is allways audio*/ |
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mtv->audio_packet_count = 1; |
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/* all systems go! init decoders */ |
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/* video - raw rgb565 */ |
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st = av_new_stream(s, VIDEO_SID); |
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if(!st) |
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return AVERROR_NOMEM; |
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av_set_pts_info(st, 64, 1, mtv->video_fps); |
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st->codec->codec_type = CODEC_TYPE_VIDEO; |
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st->codec->codec_id = CODEC_ID_RAWVIDEO; |
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st->codec->width = mtv->img_width; |
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st->codec->height = mtv->img_height; |
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st->codec->bits_per_sample = mtv->img_bpp; |
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st->codec->sample_rate = mtv->video_fps; |
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/* audio - mp3 */ |
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st = av_new_stream(s, AUDIO_SID); |
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if(!st) |
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return AVERROR_NOMEM; |
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av_set_pts_info(st, 64, 1, AUDIO_SAMPLING_RATE); |
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st->codec->codec_type = CODEC_TYPE_AUDIO; |
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st->codec->codec_id = CODEC_ID_MP3; |
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st->codec->bit_rate = mtv->audio_br; |
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st->need_parsing=1; |
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/* Jump over header */ |
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if(url_fseek(pb, MTV_HEADER_SIZE, SEEK_SET) != MTV_HEADER_SIZE) |
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return AVERROR_IO; |
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return(0); |
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} |
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static int mtv_read_packet(AVFormatContext *s, AVPacket *pkt) |
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{ |
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MTVDemuxContext *mtv = s->priv_data; |
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ByteIOContext *pb = &s->pb; |
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int ret; |
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#ifndef WORDS_BIGENDIAN |
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int i; |
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#endif |
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ret = 0; |
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if(mtv->audio_subsegments >= mtv->audio_packet_count) |
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{ |
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url_fskip(pb, MTV_AUDIO_PADDING_SIZE); |
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ret = av_get_packet(pb, pkt, MTV_ASUBCHUNK_DATA_SIZE); |
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if(ret != MTV_ASUBCHUNK_DATA_SIZE) |
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return AVERROR_IO; |
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mtv->audio_packet_count++; |
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pkt->stream_index = AUDIO_SID; |
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}else |
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{ |
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ret = av_get_packet(pb, pkt, mtv->img_segment_size); |
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if(ret != mtv->img_segment_size) |
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return AVERROR_IO; |
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#ifndef WORDS_BIGENDIAN |
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/* pkt->data is GGGRRRR BBBBBGGG
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* and we need RRRRRGGG GGGBBBBB |
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* for PIX_FMT_RGB565 so here we |
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* just swap bytes as they come |
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*/ |
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for(i=0;i<mtv->img_segment_size/2;i++) |
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*((uint16_t *)pkt->data+i) = bswap_16(*((uint16_t *)pkt->data+i)); |
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#endif |
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mtv->audio_packet_count = 1; |
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pkt->stream_index = VIDEO_SID; |
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} |
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return(ret); |
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} |
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AVInputFormat mtv_demuxer = { |
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"MTV", |
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"MTV format", |
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sizeof(MTVDemuxContext), |
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mtv_probe, |
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mtv_read_header, |
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mtv_read_packet, |
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}; |
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