COSMETICS
[libav.git] / libavformat / mtv.c
1 /*
2 * mtv demuxer
3 * Copyright (c) 2006 Reynaldo H. Verdejo Pinochet
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22 /**
23 * @file mtv.c
24 * MTV demuxer.
25 */
26
27 #include "libavutil/bswap.h"
28 #include "avformat.h"
29
30 #define MTV_ASUBCHUNK_DATA_SIZE 500
31 #define MTV_HEADER_SIZE 512
32 #define MTV_AUDIO_PADDING_SIZE 12
33 #define AUDIO_SAMPLING_RATE 44100
34 #define VIDEO_SID 0
35 #define AUDIO_SID 1
36
37 typedef struct MTVDemuxContext {
38
39 unsigned int file_size; ///< filesize, not always right
40 unsigned int segments; ///< number of 512 byte segments
41 unsigned int audio_identifier; ///< 'MP3' on all files I have seen
42 unsigned int audio_br; ///< bitrate of audio chanel (mp3)
43 unsigned int img_colorfmt; ///< frame colorfmt rgb 565/555
44 unsigned int img_bpp; ///< frame bits per pixel
45 unsigned int img_width; //
46 unsigned int img_height; //
47 unsigned int img_segment_size; ///< size of image segment
48 unsigned int video_fps; //
49 unsigned int full_segment_size;
50
51 } MTVDemuxContext;
52
53 static int mtv_probe(AVProbeData *p)
54 {
55 /* Magic is 'AMV' */
56 if(*(p->buf) != 'A' || *(p->buf+1) != 'M' || *(p->buf+2) != 'V')
57 return 0;
58
59 return AVPROBE_SCORE_MAX;
60 }
61
62 static int mtv_read_header(AVFormatContext *s, AVFormatParameters *ap)
63 {
64 MTVDemuxContext *mtv = s->priv_data;
65 ByteIOContext *pb = s->pb;
66 AVStream *st;
67 unsigned int audio_subsegments;
68
69 url_fskip(pb, 3);
70 mtv->file_size = get_le32(pb);
71 mtv->segments = get_le32(pb);
72 url_fskip(pb, 32);
73 mtv->audio_identifier = get_le24(pb);
74 mtv->audio_br = get_le16(pb);
75 mtv->img_colorfmt = get_le24(pb);
76 mtv->img_bpp = get_byte(pb);
77 mtv->img_width = get_le16(pb);
78 mtv->img_height = get_le16(pb);
79 mtv->img_segment_size = get_le16(pb);
80 url_fskip(pb, 4);
81 audio_subsegments = get_le16(pb);
82 mtv->full_segment_size =
83 audio_subsegments * (MTV_AUDIO_PADDING_SIZE + MTV_ASUBCHUNK_DATA_SIZE) +
84 mtv->img_segment_size;
85 mtv->video_fps = (mtv->audio_br / 4) / audio_subsegments;
86
87 // FIXME Add sanity check here
88
89 // all systems go! init decoders
90
91 // video - raw rgb565
92
93 st = av_new_stream(s, VIDEO_SID);
94 if(!st)
95 return AVERROR(ENOMEM);
96
97 av_set_pts_info(st, 64, 1, mtv->video_fps);
98 st->codec->codec_type = CODEC_TYPE_VIDEO;
99 st->codec->codec_id = CODEC_ID_RAWVIDEO;
100 st->codec->codec_tag = MKTAG('R', 'G', 'B', mtv->img_bpp);
101 st->codec->width = mtv->img_width;
102 st->codec->height = mtv->img_height;
103 st->codec->bits_per_coded_sample = mtv->img_bpp;
104 st->codec->sample_rate = mtv->video_fps;
105
106 // audio - mp3
107
108 st = av_new_stream(s, AUDIO_SID);
109 if(!st)
110 return AVERROR(ENOMEM);
111
112 av_set_pts_info(st, 64, 1, AUDIO_SAMPLING_RATE);
113 st->codec->codec_type = CODEC_TYPE_AUDIO;
114 st->codec->codec_id = CODEC_ID_MP3;
115 st->codec->bit_rate = mtv->audio_br;
116 st->need_parsing = AVSTREAM_PARSE_FULL;
117
118 // Jump over header
119
120 if(url_fseek(pb, MTV_HEADER_SIZE, SEEK_SET) != MTV_HEADER_SIZE)
121 return AVERROR(EIO);
122
123 return 0;
124
125 }
126
127 static int mtv_read_packet(AVFormatContext *s, AVPacket *pkt)
128 {
129 MTVDemuxContext *mtv = s->priv_data;
130 ByteIOContext *pb = s->pb;
131 int ret;
132 #ifndef WORDS_BIGENDIAN
133 int i;
134 #endif
135
136 ret = 0;
137
138 if((url_ftell(pb) - s->data_offset + mtv->img_segment_size) % mtv->full_segment_size)
139 {
140 url_fskip(pb, MTV_AUDIO_PADDING_SIZE);
141
142 ret = av_get_packet(pb, pkt, MTV_ASUBCHUNK_DATA_SIZE);
143 if(ret != MTV_ASUBCHUNK_DATA_SIZE)
144 return AVERROR(EIO);
145
146 pkt->pos -= MTV_AUDIO_PADDING_SIZE;
147 pkt->stream_index = AUDIO_SID;
148
149 }else
150 {
151 ret = av_get_packet(pb, pkt, mtv->img_segment_size);
152 if(ret != mtv->img_segment_size)
153 return AVERROR(EIO);
154
155 #ifndef WORDS_BIGENDIAN
156
157 /* pkt->data is GGGRRRR BBBBBGGG
158 * and we need RRRRRGGG GGGBBBBB
159 * for PIX_FMT_RGB565 so here we
160 * just swap bytes as they come
161 */
162
163 for(i=0;i<mtv->img_segment_size/2;i++)
164 *((uint16_t *)pkt->data+i) = bswap_16(*((uint16_t *)pkt->data+i));
165 #endif
166 pkt->stream_index = VIDEO_SID;
167 }
168
169 return ret;
170 }
171
172 AVInputFormat mtv_demuxer = {
173 "MTV",
174 NULL_IF_CONFIG_SMALL("MTV format"),
175 sizeof(MTVDemuxContext),
176 mtv_probe,
177 mtv_read_header,
178 mtv_read_packet,
179 };