FFmpeg
tmv.c
Go to the documentation of this file.
1 /*
2  * 8088flex TMV file demuxer
3  * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
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  * 8088flex TMV file demuxer
25  * @author Daniel Verkamp
26  * @see http://www.oldskool.org/pc/8088_Corruption
27  */
28 
30 #include "libavutil/intreadwrite.h"
31 #include "avformat.h"
32 #include "internal.h"
33 
34 enum {
35  TMV_PADDING = 0x01,
36  TMV_STEREO = 0x02,
37 };
38 
39 #define TMV_TAG MKTAG('T', 'M', 'A', 'V')
40 
41 typedef struct TMVContext {
42  unsigned audio_chunk_size;
43  unsigned video_chunk_size;
44  unsigned padding;
45  unsigned stream_index;
46 } TMVContext;
47 
48 #define TMV_HEADER_SIZE 12
49 
50 #define PROBE_MIN_SAMPLE_RATE 5000
51 #define PROBE_MAX_FPS 120
52 #define PROBE_MIN_AUDIO_SIZE (PROBE_MIN_SAMPLE_RATE / PROBE_MAX_FPS)
53 
54 static int tmv_probe(const AVProbeData *p)
55 {
56  if (AV_RL32(p->buf) == TMV_TAG &&
58  AV_RL16(p->buf+6) >= PROBE_MIN_AUDIO_SIZE &&
59  !p->buf[8] && // compression method
60  p->buf[9] && // char cols
61  p->buf[10]) // char rows
62  return AVPROBE_SCORE_MAX /
63  ((p->buf[9] == 40 && p->buf[10] == 25) ? 1 : 4);
64  return 0;
65 }
66 
68 {
69  TMVContext *tmv = s->priv_data;
70  AVIOContext *pb = s->pb;
71  AVStream *vst, *ast;
72  AVRational fps;
73  unsigned comp_method, char_cols, char_rows, features;
74 
75  if (avio_rl32(pb) != TMV_TAG)
76  return -1;
77 
78  if (!(vst = avformat_new_stream(s, NULL)))
79  return AVERROR(ENOMEM);
80 
81  if (!(ast = avformat_new_stream(s, NULL)))
82  return AVERROR(ENOMEM);
83 
84  ast->codecpar->sample_rate = avio_rl16(pb);
85  if (!ast->codecpar->sample_rate) {
86  av_log(s, AV_LOG_ERROR, "invalid sample rate\n");
87  return -1;
88  }
89 
90  tmv->audio_chunk_size = avio_rl16(pb);
91  if (!tmv->audio_chunk_size) {
92  av_log(s, AV_LOG_ERROR, "invalid audio chunk size\n");
93  return -1;
94  }
95 
96  comp_method = avio_r8(pb);
97  if (comp_method) {
98  av_log(s, AV_LOG_ERROR, "unsupported compression method %d\n",
99  comp_method);
100  return -1;
101  }
102 
103  char_cols = avio_r8(pb);
104  char_rows = avio_r8(pb);
105  tmv->video_chunk_size = char_cols * char_rows * 2;
106 
107  features = avio_r8(pb);
108  if (features & ~(TMV_PADDING | TMV_STEREO)) {
109  av_log(s, AV_LOG_ERROR, "unsupported features 0x%02x\n",
110  features & ~(TMV_PADDING | TMV_STEREO));
111  return -1;
112  }
113 
116  if (features & TMV_STEREO) {
117  ast->codecpar->channels = 2;
119  } else {
120  ast->codecpar->channels = 1;
122  }
124  ast->codecpar->bit_rate = ast->codecpar->sample_rate *
126  avpriv_set_pts_info(ast, 32, 1, ast->codecpar->sample_rate);
127 
128  fps.num = ast->codecpar->sample_rate * ast->codecpar->channels;
129  fps.den = tmv->audio_chunk_size;
130  av_reduce(&fps.num, &fps.den, fps.num, fps.den, 0xFFFFFFFFLL);
131 
135  vst->codecpar->width = char_cols * 8;
136  vst->codecpar->height = char_rows * 8;
137  avpriv_set_pts_info(vst, 32, fps.den, fps.num);
138 
139  if (features & TMV_PADDING)
140  tmv->padding =
141  ((tmv->video_chunk_size + tmv->audio_chunk_size + 511) & ~511) -
142  (tmv->video_chunk_size + tmv->audio_chunk_size);
143 
144  vst->codecpar->bit_rate = ((tmv->video_chunk_size + tmv->padding) *
145  fps.num * 8) / fps.den;
146 
147  return 0;
148 }
149 
151 {
152  TMVContext *tmv = s->priv_data;
153  AVIOContext *pb = s->pb;
154  int ret, pkt_size = tmv->stream_index ?
156 
157  if (avio_feof(pb))
158  return AVERROR_EOF;
159 
160  ret = av_get_packet(pb, pkt, pkt_size);
161 
162  if (tmv->stream_index)
163  avio_skip(pb, tmv->padding);
164 
165  pkt->stream_index = tmv->stream_index;
166  tmv->stream_index ^= 1;
168 
169  return ret;
170 }
171 
172 static int tmv_read_seek(AVFormatContext *s, int stream_index,
173  int64_t timestamp, int flags)
174 {
175  TMVContext *tmv = s->priv_data;
176  int64_t pos;
177 
178  if (stream_index)
179  return -1;
180 
181  pos = timestamp *
182  (tmv->audio_chunk_size + tmv->video_chunk_size + tmv->padding);
183 
184  if (avio_seek(s->pb, pos + TMV_HEADER_SIZE, SEEK_SET) < 0)
185  return -1;
186  tmv->stream_index = 0;
187  return 0;
188 }
189 
191  .name = "tmv",
192  .long_name = NULL_IF_CONFIG_SMALL("8088flex TMV"),
193  .priv_data_size = sizeof(TMVContext),
199 };
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: utils.c:4374
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
tmv_read_header
static int tmv_read_header(AVFormatContext *s)
Definition: tmv.c:67
TMVContext
Definition: tmv.c:41
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:55
AV_CH_LAYOUT_MONO
#define AV_CH_LAYOUT_MONO
Definition: channel_layout.h:90
AV_PKT_FLAG_KEY
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:404
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
AVCodecParameters::channels
int channels
Audio only.
Definition: codec_par.h:166
read_seek
static int read_seek(AVFormatContext *ctx, int stream_index, int64_t timestamp, int flags)
Definition: libcdio.c:149
ff_tmv_demuxer
const AVInputFormat ff_tmv_demuxer
Definition: tmv.c:190
tmv_read_packet
static int tmv_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: tmv.c:150
AVFMT_GENERIC_INDEX
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:468
TMV_HEADER_SIZE
#define TMV_HEADER_SIZE
Definition: tmv.c:48
av_reduce
int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max)
Reduce a fraction.
Definition: rational.c:35
avio_rl16
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:717
AVRational::num
int num
Numerator.
Definition: rational.h:59
AV_CH_LAYOUT_STEREO
#define AV_CH_LAYOUT_STEREO
Definition: channel_layout.h:91
TMVContext::padding
unsigned padding
Definition: tmv.c:44
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:626
TMV_PADDING
@ TMV_PADDING
Definition: tmv.c:35
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:257
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:631
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVCodecParameters::width
int width
Video only.
Definition: codec_par.h:126
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
TMVContext::video_chunk_size
unsigned video_chunk_size
Definition: tmv.c:43
AVFormatContext
Format I/O context.
Definition: avformat.h:1107
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:994
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:527
NULL
#define NULL
Definition: coverity.c:32
read_probe
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
tmv_probe
static int tmv_probe(const AVProbeData *p)
Definition: tmv.c:54
TMVContext::stream_index
unsigned stream_index
Definition: tmv.c:45
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:170
TMV_TAG
#define TMV_TAG
Definition: tmv.c:39
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:733
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
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:116
avpriv_set_pts_info
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:4799
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:607
AVPacket::flags
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:379
tmv_read_seek
static int tmv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Definition: tmv.c:172
AVCodecParameters::height
int height
Definition: codec_par.h:127
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:281
AV_PIX_FMT_PAL8
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:77
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:847
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:243
pos
unsigned int pos
Definition: spdifenc.c:412
avformat.h
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:92
channel_layout.h
PROBE_MIN_AUDIO_SIZE
#define PROBE_MIN_AUDIO_SIZE
Definition: tmv.c:52
AVRational::den
int den
Denominator.
Definition: rational.h:60
PROBE_MIN_SAMPLE_RATE
#define PROBE_MIN_SAMPLE_RATE
Definition: tmv.c:50
TMV_STEREO
@ TMV_STEREO
Definition: tmv.c:36
AVPacket::stream_index
int stream_index
Definition: packet.h:375
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:327
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVCodecParameters::bits_per_coded_sample
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: codec_par.h:102
AV_CODEC_ID_PCM_U8
@ AV_CODEC_ID_PCM_U8
Definition: codec_id.h:318
AVCodecParameters::format
int format
Definition: codec_par.h:84
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AVCodecParameters::channel_layout
uint64_t channel_layout
Audio only.
Definition: codec_par.h:162
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
AVCodecParameters::bit_rate
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: codec_par.h:89
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
TMVContext::audio_chunk_size
unsigned audio_chunk_size
Definition: tmv.c:42
AV_CODEC_ID_TMV
@ AV_CODEC_ID_TMV
Definition: codec_id.h:176
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:354