FFmpeg
mtv.c
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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 
53 
54 static int mtv_probe(const 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]))
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)
97 
98  return AVPROBE_SCORE_MAX;
99 }
100 
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);
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);
127  }
128 
129  /* Calculate width and height if missing from header */
130 
131  if (!mtv->img_width && mtv->img_height > 0 && mtv->img_bpp >= 8)
132  mtv->img_width=mtv->img_segment_size / (mtv->img_bpp>>3)
133  / mtv->img_height;
134 
135  if (!mtv->img_height && mtv->img_width > 0 && mtv->img_bpp >= 8)
136  mtv->img_height=mtv->img_segment_size / (mtv->img_bpp>>3)
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_INVALIDDATA;
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);
171  st->codecpar->width = mtv->img_width;
172  st->codecpar->height = mtv->img_height;
173  st->codecpar->extradata = av_strdup("BottomUp");
174  st->codecpar->extradata_size = 9;
175 
176  // audio - mp3
177 
178  st = avformat_new_stream(s, NULL);
179  if(!st)
180  return AVERROR(ENOMEM);
181 
185  st->codecpar->bit_rate = mtv->audio_br;
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 
198 {
199  MTVDemuxContext *mtv = s->priv_data;
200  AVIOContext *pb = s->pb;
201  int ret;
202 
203  if((avio_tell(pb) - s->internal->data_offset + mtv->img_segment_size) % mtv->full_segment_size)
204  {
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 
227  .name = "mtv",
228  .long_name = NULL_IF_CONFIG_SMALL("MTV"),
229  .priv_data_size = sizeof(MTVDemuxContext),
233 };
#define MTV_ASUBCHUNK_DATA_SIZE
Definition: mtv.c:32
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:161
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
#define MTV_AUDIO_SAMPLING_RATE
Definition: mtv.c:36
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1497
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4892
static int mtv_probe(const AVProbeData *p)
Definition: mtv.c:54
unsigned int img_bpp
frame bits per pixel
Definition: mtv.c:45
#define avpriv_request_sample(...)
int64_t data_offset
offset of the first packet
Definition: internal.h:82
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3957
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
AVFormatInternal * internal
An opaque field for libavformat internal usage.
Definition: avformat.h:1811
unsigned int img_width
Definition: mtv.c:46
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:334
static AVPacket pkt
unsigned int segments
number of 512 byte segments
Definition: mtv.c:41
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:87
unsigned int video_fps
Definition: mtv.c:49
#define MTV_HEADER_SIZE
Definition: mtv.c:33
Format I/O context.
Definition: avformat.h:1358
unsigned int img_colorfmt
frame colorfmt rgb 565/555
Definition: mtv.c:44
AVInputFormat ff_mtv_demuxer
Definition: mtv.c:226
int width
Video only.
Definition: avcodec.h:4023
enum AVStreamParseType need_parsing
Definition: avformat.h:1099
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4465
packed RGB 5:6:5, 16bpp, (msb) 5R 6G 5B(lsb), big-endian
Definition: pixfmt.h:105
static int mtv_read_header(AVFormatContext *s)
Definition: mtv.c:101
unsigned int audio_identifier
&#39;MP3&#39; on all files I have seen
Definition: mtv.c:42
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:310
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
#define av_log(a,...)
unsigned int file_size
filesize, not always right
Definition: mtv.c:40
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: avcodec.h:3986
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:772
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
unsigned int full_segment_size
Definition: mtv.c:50
#define MTV_IMAGE_DEFAULT_BPP
Definition: mtv.c:35
preferred ID for decoding MPEG audio layer 1, 2 or 3
Definition: avcodec.h:565
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3953
int extradata_size
Size of the extradata content in bytes.
Definition: avcodec.h:3975
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:641
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
#define s(width, name)
Definition: cbs_vp9.c:257
#define MTV_AUDIO_PADDING_SIZE
Definition: mtv.c:34
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:530
if(ret)
Stream structure.
Definition: avformat.h:881
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:251
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
unsigned int img_segment_size
size of image segment
Definition: mtv.c:48
byte swapping routines
unsigned int img_height
Definition: mtv.c:47
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:456
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
full parsing and repack
Definition: avformat.h:800
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:756
Main libavformat public API header.
unsigned int audio_br
bitrate of audio channel (mp3)
Definition: mtv.c:43
void * priv_data
Format private data.
Definition: avformat.h:1386
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: avcodec.h:3971
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:654
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
unsigned int avio_rl24(AVIOContext *s)
Definition: aviobuf.c:764
static int mtv_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: mtv.c:197
int stream_index
Definition: avcodec.h:1479
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
This structure stores compressed data.
Definition: avcodec.h:1454