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 static int isansicode(int x)
38 {
39  return x == 0x1B || x == 0x0A || x == 0x0D || (x >= 0x20 && x < 0x7f);
40 }
41 
42 static const char tty_extensions[31] = "ans,art,asc,diz,ice,nfo,txt,vt";
43 
44 typedef struct TtyDemuxContext {
45  AVClass *class;
47  uint64_t fsize; /**< file size less metadata buffer */
48  int width, height; /**< Set by a private option. */
49  AVRational framerate; /**< Set by a private option. */
51 
52 static int read_probe(const AVProbeData *p)
53 {
54  int cnt = 0;
55 
56  if (!p->buf_size)
57  return 0;
58 
59  for (int i = 0; i < 8 && i < p->buf_size; i++)
60  cnt += !!isansicode(p->buf[i]);
61 
62  if (cnt != 8)
63  return 0;
64 
65  for (int i = 8; i < p->buf_size; i++)
66  cnt += !!isansicode(p->buf[i]);
67 
68  return (cnt * 99LL / p->buf_size) * (cnt > 400) *
70 }
71 
72 /**
73  * Parse EFI header
74  */
75 static int efi_read(AVFormatContext *avctx, uint64_t start_pos)
76 {
77  TtyDemuxContext *s = avctx->priv_data;
78  AVIOContext *pb = avctx->pb;
79  char buf[37];
80  int len;
81 
82  avio_seek(pb, start_pos, SEEK_SET);
83  if (avio_r8(pb) != 0x1A)
84  return -1;
85 
86 #define GET_EFI_META(name,size) \
87  len = avio_r8(pb); \
88  if (len < 1 || len > size) \
89  return -1; \
90  if (avio_read(pb, buf, size) == size) { \
91  buf[len] = 0; \
92  av_dict_set(&avctx->metadata, name, buf, 0); \
93  }
94 
95  GET_EFI_META("filename", 12)
96  GET_EFI_META("title", 36)
97 
98  s->fsize = start_pos;
99  return 0;
100 }
101 
102 static int read_header(AVFormatContext *avctx)
103 {
104  TtyDemuxContext *s = avctx->priv_data;
105  int ret = 0;
106  AVStream *st = avformat_new_stream(avctx, NULL);
107 
108  if (!st) {
109  ret = AVERROR(ENOMEM);
110  goto fail;
111  }
112  st->codecpar->codec_tag = 0;
115 
116  st->codecpar->width = s->width;
117  st->codecpar->height = s->height;
119  st->avg_frame_rate = s->framerate;
120 
121  /* simulate tty display speed */
123 
124  if (avctx->pb->seekable & AVIO_SEEKABLE_NORMAL) {
125  s->fsize = avio_size(avctx->pb);
126  st->duration = (s->fsize + s->chars_per_frame - 1) / s->chars_per_frame;
127 
128  if (ff_sauce_read(avctx, &s->fsize, 0, 0) < 0)
129  efi_read(avctx, s->fsize - 51);
130 
131  avio_seek(avctx->pb, 0, SEEK_SET);
132  }
133 
134 fail:
135  return ret;
136 }
137 
139 {
140  TtyDemuxContext *s = avctx->priv_data;
141  int n;
142 
143  if (avio_feof(avctx->pb))
144  return AVERROR_EOF;
145 
146  n = s->chars_per_frame;
147  if (s->fsize) {
148  // ignore metadata buffer
149  uint64_t p = avio_tell(avctx->pb);
150  if (p == s->fsize)
151  return AVERROR_EOF;
152  if (p + s->chars_per_frame > s->fsize)
153  n = s->fsize - p;
154  }
155 
156  pkt->size = av_get_packet(avctx->pb, pkt, n);
157  if (pkt->size < 0)
158  return pkt->size;
159  pkt->stream_index = 0;
160  pkt->pts = pkt->pos / s->chars_per_frame;
161  pkt->flags |= AV_PKT_FLAG_KEY;
162  return 0;
163 }
164 
165 #define OFFSET(x) offsetof(TtyDemuxContext, x)
166 #define DEC AV_OPT_FLAG_DECODING_PARAM
167 static const AVOption options[] = {
168  { "chars_per_frame", "", offsetof(TtyDemuxContext, chars_per_frame), AV_OPT_TYPE_INT, {.i64 = 6000}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM},
169  { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
170  { "framerate", "", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, INT_MAX, DEC },
171  { NULL },
172 };
173 
174 static const AVClass tty_demuxer_class = {
175  .class_name = "TTY demuxer",
176  .item_name = av_default_item_name,
177  .option = options,
178  .version = LIBAVUTIL_VERSION_INT,
179 };
180 
182  .name = "tty",
183  .long_name = NULL_IF_CONFIG_SMALL("Tele-typewriter"),
184  .priv_data_size = sizeof(TtyDemuxContext),
188  .extensions = tty_extensions,
189  .priv_class = &tty_demuxer_class,
191 };
#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:334
AVOption.
Definition: opt.h:246
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
const char * filename
Definition: avformat.h:442
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:375
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:4938
uint64_t fsize
file size less metadata buffer
Definition: tty.c:47
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
int num
Numerator.
Definition: rational.h:59
int size
Definition: packet.h:356
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:241
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
static AVPacket pkt
AVRational framerate
Set by a private option.
Definition: tty.c:49
Format I/O context.
Definition: avformat.h:1351
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: codec_par.h:126
AVOptions.
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4519
#define OFFSET(x)
Definition: tty.c:165
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:304
int av_match_ext(const char *filename, const char *extensions)
Return a positive value if the given filename has one of the given extensions, 0 otherwise.
Definition: format.c:38
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: packet.h:388
int height
Set by a private option.
Definition: tty.c:48
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
#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: codec_par.h:56
static const AVOption options[]
Definition: tty.c:167
static int read_probe(const AVProbeData *p)
Definition: tty.c:52
AVRational avg_frame_rate
Average framerate.
Definition: avformat.h:949
#define FFMAX(a, b)
Definition: common.h:94
#define fail()
Definition: checkasm.h:123
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:361
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:616
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:444
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
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:166
static int read_header(AVFormatContext *avctx)
Definition: tty.c:102
#define s(width, name)
Definition: cbs_vp9.c:257
if(ret)
Stream structure.
Definition: avformat.h:876
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
static const AVClass tty_demuxer_class
Definition: tty.c:174
AVIOContext * pb
I/O context.
Definition: avformat.h:1393
AVInputFormat ff_tty_demuxer
Definition: tty.c:181
Describe the class of an AVClass context structure.
Definition: log.h:67
#define AVFMT_GENERIC_INDEX
Use generic index building code.
Definition: avformat.h:463
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
static const char tty_extensions[31]
Definition: tty.c:42
offset must point to AVRational
Definition: opt.h:236
offset must point to two consecutive integers
Definition: opt.h:233
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
misc parsing utilities
SAUCE header parser.
#define flags(name, subs,...)
Definition: cbs_av1.c:564
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:925
static int efi_read(AVFormatContext *avctx, uint64_t start_pos)
Parse EFI header.
Definition: tty.c:75
Main libavformat public API header.
int chars_per_frame
Definition: tty.c:46
int den
Denominator.
Definition: rational.h:60
static int isansicode(int x)
Definition: tty.c:37
int len
void * priv_data
Format private data.
Definition: avformat.h:1379
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:650
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1023
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:356
uint32_t codec_tag
Additional information about the codec (corresponds to the AVI FOURCC).
Definition: codec_par.h:64
int stream_index
Definition: packet.h:357
AVRational time_base
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented...
Definition: avformat.h:905
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: packet.h:332
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:348
static int read_packet(AVFormatContext *avctx, AVPacket *pkt)
Definition: tty.c:138
int width
Definition: tty.c:48