diff options
Diffstat (limited to 'ffmpeg/libavformat/mtv.c')
| -rw-r--r-- | ffmpeg/libavformat/mtv.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/ffmpeg/libavformat/mtv.c b/ffmpeg/libavformat/mtv.c new file mode 100644 index 0000000..6ffbb51 --- /dev/null +++ b/ffmpeg/libavformat/mtv.c @@ -0,0 +1,203 @@ +/* + * 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" +#include "internal.h" + +#define MTV_ASUBCHUNK_DATA_SIZE 500 +#define MTV_HEADER_SIZE 512 +#define MTV_AUDIO_PADDING_SIZE 12 +#define AUDIO_SAMPLING_RATE 44100 + +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_size < 57 || !(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) +{ + 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_bpp>>3){ + if(!mtv->img_width && mtv->img_height) + mtv->img_width=mtv->img_segment_size / (mtv->img_bpp>>3) + / mtv->img_height; + + if(!mtv->img_height && mtv->img_width) + mtv->img_height=mtv->img_segment_size / (mtv->img_bpp>>3) + / mtv->img_width; + } + if(!mtv->img_height || !mtv->img_width){ + av_log(s, AV_LOG_ERROR, "width or height is invalid and I cannot calculate them from other information\n"); + return AVERROR(EINVAL); + } + + avio_skip(pb, 4); + audio_subsegments = avio_rl16(pb); + + if (audio_subsegments == 0) { + avpriv_request_sample(s, "MTV files without audio"); + return AVERROR_PATCHWELCOME; + } + + 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 = avformat_new_stream(s, NULL); + if(!st) + return AVERROR(ENOMEM); + + avpriv_set_pts_info(st, 64, 1, mtv->video_fps); + st->codec->codec_type = AVMEDIA_TYPE_VIDEO; + st->codec->codec_id = AV_CODEC_ID_RAWVIDEO; + st->codec->pix_fmt = AV_PIX_FMT_RGB565BE; + 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 = avformat_new_stream(s, NULL); + if(!st) + return AVERROR(ENOMEM); + + avpriv_set_pts_info(st, 64, 1, AUDIO_SAMPLING_RATE); + st->codec->codec_type = AVMEDIA_TYPE_AUDIO; + st->codec->codec_id = AV_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((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 = 1; + + }else + { + ret = av_get_packet(pb, pkt, mtv->img_segment_size); + if(ret < 0) + return ret; + + pkt->stream_index = 0; + } + + return ret; +} + +AVInputFormat ff_mtv_demuxer = { + .name = "mtv", + .long_name = NULL_IF_CONFIG_SMALL("MTV"), + .priv_data_size = sizeof(MTVDemuxContext), + .read_probe = mtv_probe, + .read_header = mtv_read_header, + .read_packet = mtv_read_packet, +}; |