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 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);
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 };
SD
#define SD
Definition: microdvddec.c:193
AVMEDIA_TYPE_SUBTITLE
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
AVCodecParameters::extradata
uint8_t * extradata
Extra binary data needed for initializing the decoder, codec-dependent.
Definition: codec_par.h:74
microdvd_probe
static int microdvd_probe(const AVProbeData *p)
Definition: microdvddec.c:39
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
opt.h
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4376
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
sub
static float sub(float src0, float src1)
Definition: dnn_backend_native_layer_mathbinary.c:32
AVOption
AVOption.
Definition: opt.h:248
MicroDVDContext
Definition: microdvddec.c:32
microdvd_options
static const AVOption microdvd_options[]
Definition: microdvddec.c:194
get_pts
static int64_t get_pts(const char *buf)
Definition: microdvddec.c:58
AV_OPT_TYPE_RATIONAL
@ AV_OPT_TYPE_RATIONAL
Definition: opt.h:230
microdvd_read_packet
static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: microdvddec.c:170
microdvd_class
static const AVClass microdvd_class
Definition: microdvddec.c:199
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
MicroDVDContext::q
FFDemuxSubtitlesQueue q
Definition: microdvddec.c:34
fail
#define fail()
Definition: checkasm.h:134
read_close
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:142
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:538
pts
static int64_t pts
Definition: transcode_aac.c:652
microdvd_read_seek
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
AVRational::num
int num
Numerator.
Definition: rational.h:59
ff_subtitles_queue_seek
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:255
frame_start
static int frame_start(MpegEncContext *s)
Definition: mpegvideo_enc.c:1629
pkt
AVPacket * pkt
Definition: movenc.c:59
AVInputFormat
Definition: avformat.h:621
OFFSET
#define OFFSET(x)
Definition: microdvddec.c:192
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:626
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
ff_subtitles_queue_read_packet
int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
Generic read_packet() callback for subtitles demuxers using this queue system.
Definition: subtitles.c:216
AVFormatContext
Format I/O context.
Definition: avformat.h:1097
internal.h
MicroDVDContext::frame_rate
AVRational frame_rate
Definition: microdvddec.c:35
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:984
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:527
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
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
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
ff_subtitles_queue_insert
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
c
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
MAX_LINESIZE
#define MAX_LINESIZE
Definition: microdvddec.c:29
ff_microdvd_demuxer
const AVInputFormat ff_microdvd_demuxer
Definition: microdvddec.c:206
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:117
microdvd_read_header
static int microdvd_read_header(AVFormatContext *s)
Definition: microdvddec.c:79
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:4801
size
int size
Definition: twinvq_data.h:10344
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
ff_subtitles_queue_finalize
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:198
FFDemuxSubtitlesQueue
Definition: subtitles.h:102
microdvd_read_close
static int microdvd_read_close(AVFormatContext *s)
Definition: microdvddec.c:184
ff_subtitles_queue_clean
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:307
line
Definition: graph2dot.c:48
i
int i
Definition: input.c:407
av_d2q
AVRational av_d2q(double d, int max)
Convert a double precision floating point number to a rational.
Definition: rational.c:106
ff_get_line
int ff_get_line(AVIOContext *s, char *buf, int maxlen)
Read a whole line of text from AVIOContext.
Definition: aviobuf.c:772
len
int len
Definition: vorbis_enc_data.h:426
SKIP_FRAME_ID
#define SKIP_FRAME_ID
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:837
AVClass::class_name
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
frame
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
Definition: filter_design.txt:264
pos
unsigned int pos
Definition: spdifenc.c:412
avformat.h
subtitles.h
AVRational::den
int den
Denominator.
Definition: rational.h:60
frame_end
static void frame_end(MpegEncContext *s)
Definition: mpegvideo_enc.c:1571
AV_CODEC_ID_MICRODVD
@ AV_CODEC_ID_MICRODVD
Definition: codec_id.h:529
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:342
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
ff_subtitles_next_line
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
AV_RB24
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:97
line
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:40
bom
static const char * bom
Definition: microdvddec.c:77
ff_alloc_extradata
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:3263
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:354
get_duration
static int64_t get_duration(const char *buf)
Definition: microdvddec.c:68