FFmpeg
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 int get_duration(const char *buf)
69 {
71 
72  if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)
73  return frame_end - 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;
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 
98  if (!strncmp(line, bom, 3))
99  line += 3;
100  p = line;
101 
102  if (!len)
103  break;
104  line[strcspn(line, "\r\n")] = 0;
105  if (!*p)
106  continue;
107  if (i++ < 3) {
108  int frame;
109  double fps;
110  char c;
111 
112  if ((sscanf(line, "{%d}{}%6lf", &frame, &fps) == 2 ||
113  sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)
114  && frame <= 1 && fps > 3 && fps < 100) {
115  pts_info = av_d2q(fps, 100000);
116  has_real_fps = 1;
117  continue;
118  }
119  if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
120  st->codecpar->extradata = av_strdup(line + 11);
121  if (!st->codecpar->extradata)
122  return AVERROR(ENOMEM);
123  st->codecpar->extradata_size = strlen(st->codecpar->extradata) + 1;
124  continue;
125  }
126  }
127 #define SKIP_FRAME_ID \
128  p = strchr(p, '}'); \
129  if (!p) { \
130  av_log(s, AV_LOG_WARNING, "Invalid event \"%s\"" \
131  " at line %d\n", line, i); \
132  continue; \
133  } \
134  p++
137  if (!*p)
138  continue;
139  sub = ff_subtitles_queue_insert(&microdvd->q, p, strlen(p), 0);
140  if (!sub)
141  return AVERROR(ENOMEM);
142  sub->pos = pos;
143  sub->pts = get_pts(line);
144  sub->duration = get_duration(line);
145  }
146  ff_subtitles_queue_finalize(s, &microdvd->q);
147  if (has_real_fps) {
148  /* export the FPS info only if set in the file */
149  microdvd->frame_rate = pts_info;
150  } else if (microdvd->frame_rate.num) {
151  /* fallback on user specified frame rate */
152  pts_info = microdvd->frame_rate;
153  }
154  avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);
157  return 0;
158 }
159 
161 {
162  MicroDVDContext *microdvd = s->priv_data;
163  return ff_subtitles_queue_read_packet(&microdvd->q, pkt);
164 }
165 
166 static int microdvd_read_seek(AVFormatContext *s, int stream_index,
167  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
168 {
169  MicroDVDContext *microdvd = s->priv_data;
170  return ff_subtitles_queue_seek(&microdvd->q, s, stream_index,
171  min_ts, ts, max_ts, flags);
172 }
173 
175 {
176  MicroDVDContext *microdvd = s->priv_data;
177  ff_subtitles_queue_clean(&microdvd->q);
178  return 0;
179 }
180 
181 
182 #define OFFSET(x) offsetof(MicroDVDContext, x)
183 #define SD AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM
184 static const AVOption microdvd_options[] = {
185  { "subfps", "set the movie frame rate fallback", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, SD },
186  { NULL }
187 };
188 
189 static const AVClass microdvd_class = {
190  .class_name = "microdvddec",
191  .item_name = av_default_item_name,
192  .option = microdvd_options,
193  .version = LIBAVUTIL_VERSION_INT,
194 };
195 
197  .name = "microdvd",
198  .long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
199  .priv_data_size = sizeof(MicroDVDContext),
203  .read_seek2 = microdvd_read_seek,
205  .priv_class = &microdvd_class,
206 };
#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:166
AVOption.
Definition: opt.h:246
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
int64_t pos
byte position in stream, -1 if unknown
Definition: avcodec.h:1497
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:4892
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3957
int num
Numerator.
Definition: rational.h:59
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:297
static AVPacket pkt
Format I/O context.
Definition: avformat.h:1358
static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: microdvddec.c:160
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:182
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:208
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:1495
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
#define SD
Definition: microdvddec.c:183
#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:4465
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:259
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3953
Definition: graph2dot.c:48
static int microdvd_read_header(AVFormatContext *s)
Definition: microdvddec.c:79
int extradata_size
Size of the extradata content in bytes.
Definition: avcodec.h:3975
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:448
AVInputFormat ff_microdvd_demuxer
Definition: microdvddec.c:196
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
#define s(width, name)
Definition: cbs_vp9.c:257
static const AVClass microdvd_class
Definition: microdvddec.c:189
int ff_get_line(AVIOContext *s, char *buf, int maxlen)
Read a whole line of text from AVIOContext.
Definition: aviobuf.c:811
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:530
Stream structure.
Definition: avformat.h:881
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:245
char * av_strdup(const char *s)
Duplicate a string.
Definition: mem.c:251
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_RB24
Definition: bytestream.h:87
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
static int frame_start(MpegEncContext *s)
void * buf
Definition: avisynth_c.h:766
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:446
#define SKIP_FRAME_ID
#define flags(name, subs,...)
Definition: cbs_av1.c:561
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:458
static const AVOption microdvd_options[]
Definition: microdvddec.c:184
Main libavformat public API header.
The official guide to swscale for confused that consecutive non overlapping rectangles of slice_bottom special converter These generally are unscaled converters of common like for each output line the vertical scaler pulls lines from a ring buffer When the ring buffer does not contain the wanted line
Definition: swscale.txt:33
int den
Denominator.
Definition: rational.h:60
static int microdvd_read_close(AVFormatContext *s)
Definition: microdvddec.c:174
int len
void * priv_data
Format private data.
Definition: avformat.h:1386
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: avcodec.h:3971
static int get_duration(const char *buf)
Definition: microdvddec.c:68
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
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
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:1454
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:193
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1470
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248