FFmpeg
tty.c
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1 /*
2  * Tele-typewriter demuxer
3  * Copyright (c) 2010 Peter Ross <pross@xvid.org>
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  * Tele-typewriter demuxer
25  */
26 
27 #include "libavutil/intreadwrite.h"
28 #include "libavutil/avstring.h"
29 #include "libavutil/log.h"
30 #include "libavutil/dict.h"
31 #include "libavutil/opt.h"
32 #include "libavutil/parseutils.h"
33 #include "avformat.h"
34 #include "internal.h"
35 #include "sauce.h"
36 
37 typedef struct TtyDemuxContext {
38  AVClass *class;
40  uint64_t fsize; /**< file size less metadata buffer */
41  int width, height; /**< Set by a private option. */
42  AVRational framerate; /**< Set by a private option. */
44 
45 /**
46  * Parse EFI header
47  */
48 static int efi_read(AVFormatContext *avctx, uint64_t start_pos)
49 {
50  TtyDemuxContext *s = avctx->priv_data;
51  AVIOContext *pb = avctx->pb;
52  char buf[37];
53  int len;
54 
55  avio_seek(pb, start_pos, SEEK_SET);
56  if (avio_r8(pb) != 0x1A)
57  return -1;
58 
59 #define GET_EFI_META(name,size) \
60  len = avio_r8(pb); \
61  if (len < 1 || len > size) \
62  return -1; \
63  if (avio_read(pb, buf, size) == size) { \
64  buf[len] = 0; \
65  av_dict_set(&avctx->metadata, name, buf, 0); \
66  }
67 
68  GET_EFI_META("filename", 12)
69  GET_EFI_META("title", 36)
70 
71  s->fsize = start_pos;
72  return 0;
73 }
74 
75 static int read_header(AVFormatContext *avctx)
76 {
77  TtyDemuxContext *s = avctx->priv_data;
78  int ret = 0;
79  AVStream *st = avformat_new_stream(avctx, NULL);
80 
81  if (!st) {
82  ret = AVERROR(ENOMEM);
83  goto fail;
84  }
85  st->codecpar->codec_tag = 0;
88 
89  st->codecpar->width = s->width;
90  st->codecpar->height = s->height;
92  st->avg_frame_rate = s->framerate;
93 
94  /* simulate tty display speed */
96 
97  if (avctx->pb->seekable & AVIO_SEEKABLE_NORMAL) {
98  s->fsize = avio_size(avctx->pb);
99  st->duration = (s->fsize + s->chars_per_frame - 1) / s->chars_per_frame;
100 
101  if (ff_sauce_read(avctx, &s->fsize, 0, 0) < 0)
102  efi_read(avctx, s->fsize - 51);
103 
104  avio_seek(avctx->pb, 0, SEEK_SET);
105  }
106 
107 fail:
108  return ret;
109 }
110 
112 {
113  TtyDemuxContext *s = avctx->priv_data;
114  int n;
115 
116  if (avio_feof(avctx->pb))
117  return AVERROR_EOF;
118 
119  n = s->chars_per_frame;
120  if (s->fsize) {
121  // ignore metadata buffer
122  uint64_t p = avio_tell(avctx->pb);
123  if (p == s->fsize)
124  return AVERROR_EOF;
125  if (p + s->chars_per_frame > s->fsize)
126  n = s->fsize - p;
127  }
128 
129  pkt->size = av_get_packet(avctx->pb, pkt, n);
130  if (pkt->size < 0)
131  return pkt->size;
132  pkt->flags |= AV_PKT_FLAG_KEY;
133  return 0;
134 }
135 
136 #define OFFSET(x) offsetof(TtyDemuxContext, x)
137 #define DEC AV_OPT_FLAG_DECODING_PARAM
138 static const AVOption options[] = {
139  { "chars_per_frame", "", offsetof(TtyDemuxContext, chars_per_frame), AV_OPT_TYPE_INT, {.i64 = 6000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM},
140  { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
141  { "framerate", "", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, DEC },
142  { NULL },
143 };
144 
145 static const AVClass tty_demuxer_class = {
146  .class_name = "TTY demuxer",
147  .item_name = av_default_item_name,
148  .option = options,
149  .version = LIBAVUTIL_VERSION_INT,
150 };
151 
153  .name = "tty",
154  .long_name = NULL_IF_CONFIG_SMALL("Tele-typewriter"),
155  .priv_data_size = sizeof(TtyDemuxContext),
158  .extensions = "ans,art,asc,diz,ice,nfo,txt,vt",
159  .priv_class = &tty_demuxer_class,
160 };
#define NULL
Definition: coverity.c:32
Bytestream IO Context.
Definition: avio.h:161
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:339
AVOption.
Definition: opt.h:246
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
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:4926
uint64_t fsize
file size less metadata buffer
Definition: tty.c:40
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3968
int num
Numerator.
Definition: rational.h:59
int size
Definition: avcodec.h:1481
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:246
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
static AVPacket pkt
AVRational framerate
Set by a private option.
Definition: tty.c:42
Format I/O context.
Definition: avformat.h:1358
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
Public dictionary API.
int width
Video only.
Definition: avcodec.h:4034
AVOptions.
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4499
#define OFFSET(x)
Definition: tty.c:136
static double av_q2d(AVRational a)
Convert an AVRational to a double.
Definition: rational.h:104
#define AVERROR_EOF
End of file.
Definition: error.h:55
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 GET_EFI_META(name, size)
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: avcodec.h:1512
int height
Set by a private option.
Definition: tty.c:41
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
int ff_sauce_read(AVFormatContext *avctx, uint64_t *fsize, int *got_width, int get_height)
Definition: sauce.c:32
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3964
static const AVOption options[]
Definition: tty.c:138
AVRational avg_frame_rate
Average framerate.
Definition: avformat.h:954
#define FFMAX(a, b)
Definition: common.h:94
#define fail()
Definition: checkasm.h:122
int flags
A combination of AV_PKT_FLAG values.
Definition: avcodec.h:1486
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:641
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:260
#define DEC
Definition: tty.c:137
static int read_header(AVFormatContext *avctx)
Definition: tty.c:75
#define s(width, name)
Definition: cbs_vp9.c:257
int n
Definition: avisynth_c.h:760
if(ret)
Stream structure.
Definition: avformat.h:881
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
static const AVClass tty_demuxer_class
Definition: tty.c:145
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
AVInputFormat ff_tty_demuxer
Definition: tty.c:152
void * buf
Definition: avisynth_c.h:766
Describe the class of an AVClass context structure.
Definition: log.h:67
Rational number (pair of numerator and denominator).
Definition: rational.h:58
#define AV_OPT_FLAG_DECODING_PARAM
a generic parameter which can be set by the user for demuxing or decoding
Definition: opt.h:277
offset must point to AVRational
Definition: opt.h:236
offset must point to two consecutive integers
Definition: opt.h:233
misc parsing utilities
SAUCE header parser.
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:930
static int efi_read(AVFormatContext *avctx, uint64_t start_pos)
Parse EFI header.
Definition: tty.c:48
Main libavformat public API header.
int chars_per_frame
Definition: tty.c:39
int den
Denominator.
Definition: rational.h:60
int len
void * priv_data
Format private data.
Definition: avformat.h:1386
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
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:361
uint32_t codec_tag
Additional information about the codec (corresponds to the AVI FOURCC).
Definition: avcodec.h:3972
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:910
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:1457
static int read_packet(AVFormatContext *avctx, AVPacket *pkt)
Definition: tty.c:111
int width
Definition: tty.c:41