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2ba45a60 DM |
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 | |
24 | * MTV demuxer. | |
25 | */ | |
26 | ||
27 | #include "libavutil/bswap.h" | |
28 | #include "libavutil/intreadwrite.h" | |
29 | #include "avformat.h" | |
30 | #include "internal.h" | |
31 | ||
32 | #define MTV_ASUBCHUNK_DATA_SIZE 500 | |
33 | #define MTV_HEADER_SIZE 512 | |
34 | #define MTV_AUDIO_PADDING_SIZE 12 | |
35 | #define MTV_IMAGE_DEFAULT_BPP 16 | |
36 | #define MTV_AUDIO_SAMPLING_RATE 44100 | |
37 | ||
38 | typedef struct MTVDemuxContext { | |
39 | ||
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 channel (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; | |
51 | ||
52 | } MTVDemuxContext; | |
53 | ||
54 | static int mtv_probe(AVProbeData *p) | |
55 | { | |
56 | /* we need at least 57 bytes from the header | |
57 | * to try parsing all required fields | |
58 | */ | |
59 | if (p->buf_size < 57) | |
60 | return 0; | |
61 | ||
62 | /* Magic is 'AMV' */ | |
63 | if (*p->buf != 'A' || *(p->buf + 1) != 'M' || *(p->buf + 2) != 'V') | |
64 | return 0; | |
65 | ||
66 | /* Audio magic is always MP3 */ | |
67 | if (p->buf[43] != 'M' || p->buf[44] != 'P' || p->buf[45] != '3') | |
68 | return 0; | |
69 | ||
70 | /* Check for nonzero in bpp and (width|height) header fields */ | |
71 | if(!(p->buf[51] && AV_RL16(&p->buf[52]) | AV_RL16(&p->buf[54]))) | |
72 | return 0; | |
73 | ||
74 | /* If width or height are 0 then imagesize header field should not */ | |
75 | if(!AV_RL16(&p->buf[52]) || !AV_RL16(&p->buf[54])) | |
76 | { | |
77 | if(!!AV_RL16(&p->buf[56])) | |
78 | return AVPROBE_SCORE_EXTENSION; | |
79 | else | |
80 | return 0; | |
81 | } | |
82 | ||
83 | /* Image bpp is not an absolutely required | |
84 | * field as we latter claim it should be 16 | |
85 | * no matter what. All samples in the wild | |
86 | * are RGB565/555. | |
87 | */ | |
88 | if(p->buf[51] != MTV_IMAGE_DEFAULT_BPP) | |
89 | return AVPROBE_SCORE_EXTENSION / 2; | |
90 | ||
91 | /* We had enough data to parse header values | |
92 | * but we expect to be able to get 512 bytes | |
93 | * of header to be sure. | |
94 | */ | |
95 | if (p->buf_size < MTV_HEADER_SIZE) | |
96 | return AVPROBE_SCORE_EXTENSION; | |
97 | ||
98 | return AVPROBE_SCORE_MAX; | |
99 | } | |
100 | ||
101 | static int mtv_read_header(AVFormatContext *s) | |
102 | { | |
103 | MTVDemuxContext *mtv = s->priv_data; | |
104 | AVIOContext *pb = s->pb; | |
105 | AVStream *st; | |
106 | unsigned int audio_subsegments; | |
107 | ||
108 | avio_skip(pb, 3); | |
109 | mtv->file_size = avio_rl32(pb); | |
110 | mtv->segments = avio_rl32(pb); | |
111 | avio_skip(pb, 32); | |
112 | mtv->audio_identifier = avio_rl24(pb); | |
113 | mtv->audio_br = avio_rl16(pb); | |
114 | mtv->img_colorfmt = avio_rl24(pb); | |
115 | mtv->img_bpp = avio_r8(pb)>>3; | |
116 | mtv->img_width = avio_rl16(pb); | |
117 | mtv->img_height = avio_rl16(pb); | |
118 | mtv->img_segment_size = avio_rl16(pb); | |
119 | ||
120 | /* Assume 16bpp even if claimed otherwise. | |
121 | * We know its going to be RGBG565/555 anyway | |
122 | */ | |
123 | if (mtv->img_bpp != MTV_IMAGE_DEFAULT_BPP) { | |
124 | av_log (s, AV_LOG_WARNING, "Header claims %dbpp (!= 16). Ignoring\n", | |
125 | mtv->img_bpp); | |
126 | mtv->img_bpp = MTV_IMAGE_DEFAULT_BPP; | |
127 | } | |
128 | ||
129 | /* Calculate width and height if missing from header */ | |
130 | ||
131 | if(!mtv->img_width && mtv->img_height) | |
132 | mtv->img_width=mtv->img_segment_size / (mtv->img_bpp) | |
133 | / mtv->img_height; | |
134 | ||
135 | if(!mtv->img_height && mtv->img_width) | |
136 | mtv->img_height=mtv->img_segment_size / (mtv->img_bpp) | |
137 | / mtv->img_width; | |
138 | ||
139 | if(!mtv->img_height || !mtv->img_width || !mtv->img_segment_size){ | |
140 | av_log(s, AV_LOG_ERROR, "width or height or segment_size is invalid and I cannot calculate them from other information\n"); | |
141 | return AVERROR(EINVAL); | |
142 | } | |
143 | ||
144 | avio_skip(pb, 4); | |
145 | audio_subsegments = avio_rl16(pb); | |
146 | ||
147 | if (audio_subsegments == 0) { | |
148 | avpriv_request_sample(s, "MTV files without audio"); | |
149 | return AVERROR_PATCHWELCOME; | |
150 | } | |
151 | ||
152 | mtv->full_segment_size = | |
153 | audio_subsegments * (MTV_AUDIO_PADDING_SIZE + MTV_ASUBCHUNK_DATA_SIZE) + | |
154 | mtv->img_segment_size; | |
155 | mtv->video_fps = (mtv->audio_br / 4) / audio_subsegments; | |
156 | ||
157 | // FIXME Add sanity check here | |
158 | ||
159 | // all systems go! init decoders | |
160 | ||
161 | // video - raw rgb565 | |
162 | ||
163 | st = avformat_new_stream(s, NULL); | |
164 | if(!st) | |
165 | return AVERROR(ENOMEM); | |
166 | ||
167 | avpriv_set_pts_info(st, 64, 1, mtv->video_fps); | |
168 | st->codec->codec_type = AVMEDIA_TYPE_VIDEO; | |
169 | st->codec->codec_id = AV_CODEC_ID_RAWVIDEO; | |
170 | st->codec->pix_fmt = AV_PIX_FMT_RGB565BE; | |
171 | st->codec->width = mtv->img_width; | |
172 | st->codec->height = mtv->img_height; | |
173 | st->codec->extradata = av_strdup("BottomUp"); | |
174 | st->codec->extradata_size = 9; | |
175 | ||
176 | // audio - mp3 | |
177 | ||
178 | st = avformat_new_stream(s, NULL); | |
179 | if(!st) | |
180 | return AVERROR(ENOMEM); | |
181 | ||
182 | avpriv_set_pts_info(st, 64, 1, MTV_AUDIO_SAMPLING_RATE); | |
183 | st->codec->codec_type = AVMEDIA_TYPE_AUDIO; | |
184 | st->codec->codec_id = AV_CODEC_ID_MP3; | |
185 | st->codec->bit_rate = mtv->audio_br; | |
186 | st->need_parsing = AVSTREAM_PARSE_FULL; | |
187 | ||
188 | // Jump over header | |
189 | ||
190 | if(avio_seek(pb, MTV_HEADER_SIZE, SEEK_SET) != MTV_HEADER_SIZE) | |
191 | return AVERROR(EIO); | |
192 | ||
193 | return 0; | |
194 | ||
195 | } | |
196 | ||
197 | static int mtv_read_packet(AVFormatContext *s, AVPacket *pkt) | |
198 | { | |
199 | MTVDemuxContext *mtv = s->priv_data; | |
200 | AVIOContext *pb = s->pb; | |
201 | int ret; | |
202 | ||
203 | if((avio_tell(pb) - s->data_offset + mtv->img_segment_size) % mtv->full_segment_size) | |
204 | { | |
205 | avio_skip(pb, MTV_AUDIO_PADDING_SIZE); | |
206 | ||
207 | ret = av_get_packet(pb, pkt, MTV_ASUBCHUNK_DATA_SIZE); | |
208 | if(ret < 0) | |
209 | return ret; | |
210 | ||
211 | pkt->pos -= MTV_AUDIO_PADDING_SIZE; | |
212 | pkt->stream_index = 1; | |
213 | ||
214 | }else | |
215 | { | |
216 | ret = av_get_packet(pb, pkt, mtv->img_segment_size); | |
217 | if(ret < 0) | |
218 | return ret; | |
219 | ||
220 | pkt->stream_index = 0; | |
221 | } | |
222 | ||
223 | return ret; | |
224 | } | |
225 | ||
226 | AVInputFormat ff_mtv_demuxer = { | |
227 | .name = "mtv", | |
228 | .long_name = NULL_IF_CONFIG_SMALL("MTV"), | |
229 | .priv_data_size = sizeof(MTVDemuxContext), | |
230 | .read_probe = mtv_probe, | |
231 | .read_header = mtv_read_header, | |
232 | .read_packet = mtv_read_packet, | |
233 | }; |