FFmpeg: libavformat/mtv.c Source File

FFmpeg
mtv.c
Go to the documentation of this file.
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(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]))
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);
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 > 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);
168  st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
169  st->codecpar->codec_id = AV_CODEC_ID_RAWVIDEO;
170  st->codecpar->format = AV_PIX_FMT_RGB565BE;
171  st->codecpar->width = mtv->img_width;
172  st->codecpar->height = mtv->img_height;
173  st->codecpar->extradata = av_strdup("BottomUp");
174  if (!st->codecpar->extradata)
175  return AVERROR(ENOMEM);
176  st->codecpar->extradata_size = 9;
177 
178  // audio - mp3
179 
180  st = avformat_new_stream(s, NULL);
181  if(!st)
182  return AVERROR(ENOMEM);
183 
184  avpriv_set_pts_info(st, 64, 1, MTV_AUDIO_SAMPLING_RATE);
185  st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
186  st->codecpar->codec_id = AV_CODEC_ID_MP3;
187  st->codecpar->bit_rate = mtv->audio_br;
188  ffstream(st)->need_parsing = AVSTREAM_PARSE_FULL;
189 
190  // Jump over header
191 
192  if(avio_seek(pb, MTV_HEADER_SIZE, SEEK_SET) != MTV_HEADER_SIZE)
193  return AVERROR(EIO);
194 
195  return 0;
196 
197 }
198 
199  static int mtv_read_packet(AVFormatContext *s, AVPacket *pkt)
200 {
201  MTVDemuxContext *mtv = s->priv_data;
202  AVIOContext *pb = s->pb;
203  int ret;
204 
205  if((avio_tell(pb) - ffformatcontext(s)->data_offset + mtv->img_segment_size) % mtv->full_segment_size)
206  {
207  avio_skip(pb, MTV_AUDIO_PADDING_SIZE);
208 
209  ret = av_get_packet(pb, pkt, MTV_ASUBCHUNK_DATA_SIZE);
210  if(ret < 0)
211  return ret;
212 
213  pkt->pos -= MTV_AUDIO_PADDING_SIZE;
214  pkt->stream_index = 1;
215 
216  }else
217  {
218  ret = av_get_packet(pb, pkt, mtv->img_segment_size);
219  if(ret < 0)
220  return ret;
221 
222  pkt->stream_index = 0;
223  }
224 
225  return ret;
226 }
227 
228  const AVInputFormat ff_mtv_demuxer = {
229  .name = "mtv",
230  .long_name = NULL_IF_CONFIG_SMALL("MTV"),
231  .priv_data_size = sizeof(MTVDemuxContext),
232  .read_probe = mtv_probe,
233  .read_header = mtv_read_header,
234  .read_packet = mtv_read_packet,
235 };
MTVDemuxContext::file_size
unsigned int file_size
filesize, not always right
Definition: mtv.c:40
mtv_read_packet
static int mtv_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: mtv.c:199
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
AVCodecParameters::extradata
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: codec_par.h:75
MTVDemuxContext::full_segment_size
unsigned int full_segment_size
Definition: mtv.c:50
AVERROR
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
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: options.c:237
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:57
ffformatcontext
static av_always_inline FFFormatContext * ffformatcontext(AVFormatContext *s)
Definition: internal.h:192
AV_CODEC_ID_RAWVIDEO
@ AV_CODEC_ID_RAWVIDEO
Definition: codec_id.h:63
MTV_HEADER_SIZE
#define MTV_HEADER_SIZE
Definition: mtv.c:33
mtv_probe
static int mtv_probe(const AVProbeData *p)
Definition: mtv.c:54
AVProbeData::buf_size
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:456
MTVDemuxContext::img_segment_size
unsigned int img_segment_size
size of image segment
Definition: mtv.c:48
MTVDemuxContext::img_height
unsigned int img_height
Definition: mtv.c:47
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:465
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: avformat.c:697
ffstream
static av_always_inline FFStream * ffstream(AVStream *st)
Definition: internal.h:407
MTV_IMAGE_DEFAULT_BPP
#define MTV_IMAGE_DEFAULT_BPP
Definition: mtv.c:35
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:505
AV_CODEC_ID_MP3
@ AV_CODEC_ID_MP3
preferred ID for decoding MPEG audio layer 1, 2 or 3
Definition: codec_id.h:428
avio_rl16
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:743
MTVDemuxContext::audio_br
unsigned int audio_br
bitrate of audio channel (mp3)
Definition: mtv.c:43
pkt
AVPacket * pkt
Definition: movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
AVInputFormat
Definition: avformat.h:656
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:256
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:661
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:455
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVCodecParameters::width
int width
Video only.
Definition: codec_par.h:127
MTV_AUDIO_SAMPLING_RATE
#define MTV_AUDIO_SAMPLING_RATE
Definition: mtv.c:36
AV_RL16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:94
if
if(ret)
Definition: filter_design.txt:179
FFStream::need_parsing
enum AVStreamParseType need_parsing
Definition: internal.h:380
AVFormatContext
Format I/O context.
Definition: avformat.h:1213
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1108
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:532
NULL
#define NULL
Definition: coverity.c:32
mtv_read_header
static int mtv_read_header(AVFormatContext *s)
Definition: mtv.c:101
AVERROR_PATCHWELCOME
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:64
read_probe
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
MTVDemuxContext::img_bpp
unsigned int img_bpp
frame bits per pixel
Definition: mtv.c:45
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:453
MTVDemuxContext::segments
unsigned int segments
number of 512 byte segments
Definition: mtv.c:41
MTVDemuxContext::video_fps
unsigned int video_fps
Definition: mtv.c:49
AVPROBE_SCORE_EXTENSION
#define AVPROBE_SCORE_EXTENSION
score for file extension
Definition: avformat.h:463
AVCodecParameters::extradata_size
int extradata_size
Size of the extradata content in bytes.
Definition: codec_par.h:79
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:759
AVIOContext
Bytestream IO Context.
Definition: avio.h:162
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
MTV_AUDIO_PADDING_SIZE
#define MTV_AUDIO_PADDING_SIZE
Definition: mtv.c:34
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:632
MTVDemuxContext::img_width
unsigned int img_width
Definition: mtv.c:46
MTV_ASUBCHUNK_DATA_SIZE
#define MTV_ASUBCHUNK_DATA_SIZE
Definition: mtv.c:32
avio_rl24
unsigned int avio_rl24(AVIOContext *s)
Definition: aviobuf.c:751
AVCodecParameters::height
int height
Definition: codec_par.h:128
av_get_packet
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:102
ret
ret
Definition: filter_design.txt:187
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
AVStream
Stream structure.
Definition: avformat.h:948
bswap.h
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:260
avformat.h
MTVDemuxContext::img_colorfmt
unsigned int img_colorfmt
frame colorfmt rgb 565/555
Definition: mtv.c:44
AVPacket::stream_index
int stream_index
Definition: packet.h:376
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:347
AV_PIX_FMT_RGB565BE
@ AV_PIX_FMT_RGB565BE
packed RGB 5:6:5, 16bpp, (msb) 5R 6G 5B(lsb), big-endian
Definition: pixfmt.h:105
av_strdup
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:280
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
avpriv_request_sample
#define avpriv_request_sample(...)
Definition: tableprint_vlc.h:36
AVCodecParameters::format
int format
Definition: codec_par.h:85
MTVDemuxContext
Definition: mtv.c:38
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:61
AVPacket
This structure stores compressed data.
Definition: packet.h:351
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:394
AVSTREAM_PARSE_FULL
@ AVSTREAM_PARSE_FULL
full parsing and repack
Definition: avformat.h:798
AVCodecParameters::bit_rate
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: codec_par.h:90
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
MTVDemuxContext::audio_identifier
unsigned int audio_identifier
'MP3' on all files I have seen
Definition: mtv.c:42
ff_mtv_demuxer
const AVInputFormat ff_mtv_demuxer
Definition: mtv.c:228
Generated on Wed Aug 24 2022 21:42:17 for FFmpeg by   doxygen 1.8.17

AltStyle によって変換されたページ (->オリジナル) /