FFmpeg  4.3.6
microdvddec.c
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1 /*
2  * MicroDVD subtitle demuxer
3  * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
4  * Copyright (c) 2012 Clément Bœsch <u pkh me>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "avformat.h"
24 #include "internal.h"
25 #include "subtitles.h"
26 #include "libavutil/intreadwrite.h"
27 #include "libavutil/opt.h"
28 
29 #define MAX_LINESIZE 2048
30 
31 
32 typedef struct {
33  const AVClass *class;
37 
38 
39 static int microdvd_probe(const AVProbeData *p)
40 {
41  unsigned char c;
42  const uint8_t *ptr = p->buf;
43  int i;
44 
45  if (AV_RB24(ptr) == 0xEFBBBF)
46  ptr += 3; /* skip UTF-8 BOM */
47 
48  for (i=0; i<3; i++) {
49  if (sscanf(ptr, "{%*d}{}%c", &c) != 1 &&
50  sscanf(ptr, "{%*d}{%*d}%c", &c) != 1 &&
51  sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
52  return 0;
53  ptr += ff_subtitles_next_line(ptr);
54  }
55  return AVPROBE_SCORE_MAX;
56 }
57 
58 static int64_t get_pts(const char *buf)
59 {
60  int frame;
61  char c;
62 
63  if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
64  return frame;
65  return AV_NOPTS_VALUE;
66 }
67 
68 static int64_t get_duration(const char *buf)
69 {
71 
72  if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)
73  return frame_end - (int64_t)frame_start;
74  return -1;
75 }
76 
77 static const char *bom = "\xEF\xBB\xBF";
78 
80 {
81  AVRational pts_info = (AVRational){ 2997, 125 }; /* default: 23.976 fps */
82  MicroDVDContext *microdvd = s->priv_data;
84  int i = 0, ret;
85  char line_buf[MAX_LINESIZE];
86  int has_real_fps = 0;
87 
88  if (!st)
89  return AVERROR(ENOMEM);
90 
91  while (!avio_feof(s->pb)) {
92  char *p;
93  AVPacket *sub;
94  int64_t pos = avio_tell(s->pb);
95  int len = ff_get_line(s->pb, line_buf, sizeof(line_buf));
96  char *line = line_buf;
97  int64_t pts;
98 
99  if (!strncmp(line, bom, 3))
100  line += 3;
101  p = line;
102 
103  if (!len)
104  break;
105  line[strcspn(line, "\r\n")] = 0;
106  if (!*p)
107  continue;
108  if (i++ < 3) {
109  int frame;
110  double fps;
111  char c;
112 
113  if ((sscanf(line, "{%d}{}%6lf", &frame, &fps) == 2 ||
114  sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)
115  && frame <= 1 && fps > 3 && fps < 100) {
116  pts_info = av_d2q(fps, 100000);
117  has_real_fps = 1;
118  continue;
119  }
120  if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
121  int size = strlen(line + 11);
122  ret = ff_alloc_extradata(st->codecpar, size);
123  if (ret < 0)
124  goto fail;
125  memcpy(st->codecpar->extradata, line + 11, size);
126  continue;
127  }
128  }
129 #define SKIP_FRAME_ID \
130  p = strchr(p, '}'); \
131  if (!p) { \
132  av_log(s, AV_LOG_WARNING, "Invalid event \"%s\"" \
133  " at line %d\n", line, i); \
134  continue; \
135  } \
136  p++
139  if (!*p)
140  continue;
141  pts = get_pts(line);
142  if (pts == AV_NOPTS_VALUE)
143  continue;
144  sub = ff_subtitles_queue_insert(&microdvd->q, p, strlen(p), 0);
145  if (!sub) {
146  ret = AVERROR(ENOMEM);
147  goto fail;
148  }
149  sub->pos = pos;
150  sub->pts = pts;
151  sub->duration = get_duration(line);
152  }
153  ff_subtitles_queue_finalize(s, &microdvd->q);
154  if (has_real_fps) {
155  /* export the FPS info only if set in the file */
156  microdvd->frame_rate = pts_info;
157  } else if (microdvd->frame_rate.num) {
158  /* fallback on user specified frame rate */
159  pts_info = microdvd->frame_rate;
160  }
161  avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);
164  return 0;
165 fail:
166  ff_subtitles_queue_clean(&microdvd->q);
167  return ret;
168 }
169 
171 {
172  MicroDVDContext *microdvd = s->priv_data;
173  return ff_subtitles_queue_read_packet(&microdvd->q, pkt);
174 }
175 
176 static int microdvd_read_seek(AVFormatContext *s, int stream_index,
177  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
178 {
179  MicroDVDContext *microdvd = s->priv_data;
180  return ff_subtitles_queue_seek(&microdvd->q, s, stream_index,
181  min_ts, ts, max_ts, flags);
182 }
183 
185 {
186  MicroDVDContext *microdvd = s->priv_data;
187  ff_subtitles_queue_clean(&microdvd->q);
188  return 0;
189 }
190 
191 
192 #define OFFSET(x) offsetof(MicroDVDContext, x)
193 #define SD AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM
194 static const AVOption microdvd_options[] = {
195  { "subfps", "set the movie frame rate fallback", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, SD },
196  { NULL }
197 };
198 
199 static const AVClass microdvd_class = {
200  .class_name = "microdvddec",
201  .item_name = av_default_item_name,
202  .option = microdvd_options,
203  .version = LIBAVUTIL_VERSION_INT,
204 };
205 
207  .name = "microdvd",
208  .long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
209  .priv_data_size = sizeof(MicroDVDContext),
213  .read_seek2 = microdvd_read_seek,
215  .priv_class = &microdvd_class,
216 };
#define NULL
Definition: coverity.c:32
static int microdvd_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Definition: microdvddec.c:176
int size
AVOption.
Definition: opt.h:246
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
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:4948
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
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
#define AV_RB24
Definition: intreadwrite.h:64
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:302
static AVPacket pkt
Format I/O context.
Definition: avformat.h:1351
static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: microdvddec.c:170
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
#define OFFSET(x)
Definition: microdvddec.c:192
uint8_t
AVOptions.
int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
Generic read_packet() callback for subtitles demuxers using this queue system.
Definition: subtitles.c:212
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:373
#define SD
Definition: microdvddec.c:193
#define MAX_LINESIZE
Definition: microdvddec.c:29
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4526
static AVFrame * frame
static int64_t get_pts(const char *buf)
Definition: microdvddec.c:58
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:145
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
static const char * bom
Definition: microdvddec.c:77
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:188
unsigned int pos
Definition: spdifenc.c:412
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
Definition: graph2dot.c:48
#define fail()
Definition: checkasm.h:123
static int microdvd_read_header(AVFormatContext *s)
Definition: microdvddec.c:79
static void frame_end(MpegEncContext *s)
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
int ff_alloc_extradata(AVCodecParameters *par, int size)
Allocate extradata with additional AV_INPUT_BUFFER_PADDING_SIZE at end which is always set to 0...
Definition: utils.c:3328
AVInputFormat ff_microdvd_demuxer
Definition: microdvddec.c:206
#define s(width, name)
Definition: cbs_vp9.c:257
static const AVClass microdvd_class
Definition: microdvddec.c:199
int ff_get_line(AVIOContext *s, char *buf, int maxlen)
Read a whole line of text from AVIOContext.
Definition: aviobuf.c:786
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:545
Stream structure.
Definition: avformat.h:876
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Update current_sub_idx to emulate a seek.
Definition: subtitles.c:250
AVIOContext * pb
I/O context.
Definition: avformat.h:1393
static int frame_start(MpegEncContext *s)
FFDemuxSubtitlesQueue q
Definition: microdvddec.c:34
Describe the class of an AVClass context structure.
Definition: log.h:67
Rational number (pair of numerator and denominator).
Definition: rational.h:58
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
static int64_t pts
#define SKIP_FRAME_ID
#define flags(name, subs,...)
Definition: cbs_av1.c:565
static av_always_inline int ff_subtitles_next_line(const char *ptr)
Get the number of characters to increment to jump to the next line, or to the end of the string...
Definition: subtitles.h:187
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
AVRational av_d2q(double d, int max)
Convert a double precision floating point number to a rational.
Definition: rational.c:106
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
static const AVOption microdvd_options[]
Definition: microdvddec.c:194
Main libavformat public API header.
static double c[64]
int den
Denominator.
Definition: rational.h:60
static int microdvd_read_close(AVFormatContext *s)
Definition: microdvddec.c:184
int len
void * priv_data
Format private data.
Definition: avformat.h:1379
static int microdvd_probe(const AVProbeData *p)
Definition: microdvddec.c:39
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: codec_par.h:74
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
AVPacket * ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q, const uint8_t *event, size_t len, int merge)
Insert a new subtitle event.
Definition: subtitles.c:111
static int64_t get_duration(const char *buf)
Definition: microdvddec.c:68
This structure stores compressed data.
Definition: packet.h:332
AVRational frame_rate
Definition: microdvddec.c:35
void ff_subtitles_queue_finalize(void *log_ctx, FFDemuxSubtitlesQueue *q)
Set missing durations, sort subtitles by PTS (and then byte position), and drop duplicated events...
Definition: subtitles.c:194
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:348
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248