/* * mtv demuxer * Copyright (c) 2006 Reynaldo H. Verdejo Pinochet * * 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 */ /** * @file * MTV demuxer. */ #include "libavutil/bswap.h" #include "libavutil/intreadwrite.h" #include "avformat.h" #define MTV_ASUBCHUNK_DATA_SIZE 500 #define MTV_HEADER_SIZE 512 #define MTV_AUDIO_PADDING_SIZE 12 #define AUDIO_SAMPLING_RATE 44100 #define VIDEO_SID 0 #define AUDIO_SID 1 typedef struct MTVDemuxContext { unsigned int file_size; ///< filesize, not always right unsigned int segments; ///< number of 512 byte segments unsigned int audio_identifier; ///< 'MP3' on all files I have seen unsigned int audio_br; ///< bitrate of audio channel (mp3) unsigned int img_colorfmt; ///< frame colorfmt rgb 565/555 unsigned int img_bpp; ///< frame bits per pixel unsigned int img_width; // unsigned int img_height; // unsigned int img_segment_size; ///< size of image segment unsigned int video_fps; // unsigned int full_segment_size; } MTVDemuxContext; static int mtv_probe(AVProbeData *p) { /* Magic is 'AMV' */ if(*(p->buf) != 'A' || *(p->buf+1) != 'M' || *(p->buf+2) != 'V') return 0; /* Check for nonzero in bpp and (width|height) header fields */ if(!(p->buf[51] && AV_RL16(&p->buf[52]) | AV_RL16(&p->buf[54]))) return 0; /* If width or height are 0 then imagesize header field should not */ if(!AV_RL16(&p->buf[52]) || !AV_RL16(&p->buf[54])) { if(!!AV_RL16(&p->buf[56])) return AVPROBE_SCORE_MAX/2; else return 0; } if(p->buf[51] != 16) return AVPROBE_SCORE_MAX/4; // But we are going to assume 16bpp anyway .. return AVPROBE_SCORE_MAX; } static int mtv_read_header(AVFormatContext *s, AVFormatParameters *ap) { MTVDemuxContext *mtv = s->priv_data; AVIOContext *pb = s->pb; AVStream *st; unsigned int audio_subsegments; avio_skip(pb, 3); mtv->file_size = avio_rl32(pb); mtv->segments = avio_rl32(pb); avio_skip(pb, 32); mtv->audio_identifier = avio_rl24(pb); mtv->audio_br = avio_rl16(pb); mtv->img_colorfmt = avio_rl24(pb); mtv->img_bpp = avio_r8(pb); mtv->img_width = avio_rl16(pb); mtv->img_height = avio_rl16(pb); mtv->img_segment_size = avio_rl16(pb); /* Calculate width and height if missing from header */ if(!mtv->img_width) mtv->img_width=mtv->img_segment_size / (mtv->img_bpp>>3) / mtv->img_height; if(!mtv->img_height) mtv->img_height=mtv->img_segment_size / (mtv->img_bpp>>3) / mtv->img_width; avio_skip(pb, 4); audio_subsegments = avio_rl16(pb); mtv->full_segment_size = audio_subsegments * (MTV_AUDIO_PADDING_SIZE + MTV_ASUBCHUNK_DATA_SIZE) + mtv->img_segment_size; mtv->video_fps = (mtv->audio_br / 4) / audio_subsegments; // FIXME Add sanity check here // all systems go! init decoders // video - raw rgb565 st = av_new_stream(s, VIDEO_SID); if(!st) return AVERROR(ENOMEM); av_set_pts_info(st, 64, 1, mtv->video_fps); st->codec->codec_type = AVMEDIA_TYPE_VIDEO; st->codec->codec_id = CODEC_ID_RAWVIDEO; st->codec->pix_fmt = PIX_FMT_RGB565; st->codec->width = mtv->img_width; st->codec->height = mtv->img_height; st->codec->sample_rate = mtv->video_fps; st->codec->extradata = av_strdup("BottomUp"); st->codec->extradata_size = 9; // audio - mp3 st = av_new_stream(s, AUDIO_SID); if(!st) return AVERROR(ENOMEM); av_set_pts_info(st, 64, 1, AUDIO_SAMPLING_RATE); st->codec->codec_type = AVMEDIA_TYPE_AUDIO; st->codec->codec_id = CODEC_ID_MP3; st->codec->bit_rate = mtv->audio_br; st->need_parsing = AVSTREAM_PARSE_FULL; // Jump over header if(avio_seek(pb, MTV_HEADER_SIZE, SEEK_SET) != MTV_HEADER_SIZE) return AVERROR(EIO); return 0; } static int mtv_read_packet(AVFormatContext *s, AVPacket *pkt) { MTVDemuxContext *mtv = s->priv_data; AVIOContext *pb = s->pb; int ret; #if !HAVE_BIGENDIAN int i; #endif if((avio_tell(pb) - s->data_offset + mtv->img_segment_size) % mtv->full_segment_size) { avio_skip(pb, MTV_AUDIO_PADDING_SIZE); ret = av_get_packet(pb, pkt, MTV_ASUBCHUNK_DATA_SIZE); if(ret < 0) return ret; pkt->pos -= MTV_AUDIO_PADDING_SIZE; pkt->stream_index = AUDIO_SID; }else { ret = av_get_packet(pb, pkt, mtv->img_segment_size); if(ret < 0) return ret; #if !HAVE_BIGENDIAN /* pkt->data is GGGRRRR BBBBBGGG * and we need RRRRRGGG GGGBBBBB * for PIX_FMT_RGB565 so here we * just swap bytes as they come */ for(i=0;i<mtv->img_segment_size/2;i++) *((uint16_t *)pkt->data+i) = av_bswap16(*((uint16_t *)pkt->data+i)); #endif pkt->stream_index = VIDEO_SID; } return ret; } AVInputFormat ff_mtv_demuxer = { .name = "MTV", .long_name = NULL_IF_CONFIG_SMALL("MTV format"), .priv_data_size = sizeof(MTVDemuxContext), .read_probe = mtv_probe, .read_header = mtv_read_header, .read_packet = mtv_read_packet, };