3 * Copyright (c) 2006 Reynaldo H. Verdejo Pinochet
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * @file libavformat/mtv.c
27 #include "libavutil/bswap.h"
28 #include "libavutil/intreadwrite.h"
31 #define MTV_ASUBCHUNK_DATA_SIZE 500
32 #define MTV_HEADER_SIZE 512
33 #define MTV_AUDIO_PADDING_SIZE 12
34 #define AUDIO_SAMPLING_RATE 44100
38 typedef struct MTVDemuxContext {
40 unsigned int file_size; ///< filesize, not always right
41 unsigned int segments; ///< number of 512 byte segments
42 unsigned int audio_identifier; ///< 'MP3' on all files I have seen
43 unsigned int audio_br; ///< bitrate of audio chanel (mp3)
44 unsigned int img_colorfmt; ///< frame colorfmt rgb 565/555
45 unsigned int img_bpp; ///< frame bits per pixel
46 unsigned int img_width; //
47 unsigned int img_height; //
48 unsigned int img_segment_size; ///< size of image segment
49 unsigned int video_fps; //
50 unsigned int full_segment_size;
54 static int mtv_probe(AVProbeData *p)
57 if(*(p->buf) != 'A' || *(p->buf+1) != 'M' || *(p->buf+2) != 'V')
60 /* Check for nonzero in bpp and (width|height) header fields */
61 if(!(p->buf[51] && AV_RL16(&p->buf[52]) | AV_RL16(&p->buf[54])))
64 /* If width or height are 0 then imagesize header field should not */
65 if(AV_RL16(&p->buf[52]) && AV_RL16(&p->buf[54]))
67 if(!!AV_RL16(&p->buf[56]))
68 return AVPROBE_SCORE_MAX/2;
73 return AVPROBE_SCORE_MAX;
76 static int mtv_read_header(AVFormatContext *s, AVFormatParameters *ap)
78 MTVDemuxContext *mtv = s->priv_data;
79 ByteIOContext *pb = s->pb;
81 unsigned int audio_subsegments;
84 mtv->file_size = get_le32(pb);
85 mtv->segments = get_le32(pb);
87 mtv->audio_identifier = get_le24(pb);
88 mtv->audio_br = get_le16(pb);
89 mtv->img_colorfmt = get_le24(pb);
90 mtv->img_bpp = get_byte(pb);
91 mtv->img_width = get_le16(pb);
92 mtv->img_height = get_le16(pb);
93 mtv->img_segment_size = get_le16(pb);
95 /* Calculate width and height if missing from header */
98 mtv->img_width=mtv->img_segment_size / (mtv->img_bpp>>3)
102 mtv->img_height=mtv->img_segment_size / (mtv->img_bpp>>3)
106 audio_subsegments = get_le16(pb);
107 mtv->full_segment_size =
108 audio_subsegments * (MTV_AUDIO_PADDING_SIZE + MTV_ASUBCHUNK_DATA_SIZE) +
109 mtv->img_segment_size;
110 mtv->video_fps = (mtv->audio_br / 4) / audio_subsegments;
112 // FIXME Add sanity check here
114 // all systems go! init decoders
116 // video - raw rgb565
118 st = av_new_stream(s, VIDEO_SID);
120 return AVERROR(ENOMEM);
122 av_set_pts_info(st, 64, 1, mtv->video_fps);
123 st->codec->codec_type = CODEC_TYPE_VIDEO;
124 st->codec->codec_id = CODEC_ID_RAWVIDEO;
125 st->codec->codec_tag = MKTAG('R', 'G', 'B', mtv->img_bpp);
126 st->codec->width = mtv->img_width;
127 st->codec->height = mtv->img_height;
128 st->codec->bits_per_coded_sample = mtv->img_bpp;
129 st->codec->sample_rate = mtv->video_fps;
130 st->codec->extradata = av_strdup("BottomUp");
131 st->codec->extradata_size = 9;
135 st = av_new_stream(s, AUDIO_SID);
137 return AVERROR(ENOMEM);
139 av_set_pts_info(st, 64, 1, AUDIO_SAMPLING_RATE);
140 st->codec->codec_type = CODEC_TYPE_AUDIO;
141 st->codec->codec_id = CODEC_ID_MP3;
142 st->codec->bit_rate = mtv->audio_br;
143 st->need_parsing = AVSTREAM_PARSE_FULL;
147 if(url_fseek(pb, MTV_HEADER_SIZE, SEEK_SET) != MTV_HEADER_SIZE)
154 static int mtv_read_packet(AVFormatContext *s, AVPacket *pkt)
156 MTVDemuxContext *mtv = s->priv_data;
157 ByteIOContext *pb = s->pb;
163 if((url_ftell(pb) - s->data_offset + mtv->img_segment_size) % mtv->full_segment_size)
165 url_fskip(pb, MTV_AUDIO_PADDING_SIZE);
167 ret = av_get_packet(pb, pkt, MTV_ASUBCHUNK_DATA_SIZE);
168 if(ret != MTV_ASUBCHUNK_DATA_SIZE)
171 pkt->pos -= MTV_AUDIO_PADDING_SIZE;
172 pkt->stream_index = AUDIO_SID;
176 ret = av_get_packet(pb, pkt, mtv->img_segment_size);
177 if(ret != mtv->img_segment_size)
182 /* pkt->data is GGGRRRR BBBBBGGG
183 * and we need RRRRRGGG GGGBBBBB
184 * for PIX_FMT_RGB565 so here we
185 * just swap bytes as they come
188 for(i=0;i<mtv->img_segment_size/2;i++)
189 *((uint16_t *)pkt->data+i) = bswap_16(*((uint16_t *)pkt->data+i));
191 pkt->stream_index = VIDEO_SID;
197 AVInputFormat mtv_demuxer = {
199 NULL_IF_CONFIG_SMALL("MTV format"),
200 sizeof(MTVDemuxContext),