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 "demux.h"
25 #include "internal.h"
26 #include "subtitles.h"
27 #include "libavutil/intreadwrite.h"
28 #include "libavutil/opt.h"
29 
30 #define MAX_LINESIZE 2048
31 
32 
33 typedef struct {
34  const AVClass *class;
38 
39 
40 static int microdvd_probe(const AVProbeData *p)
41 {
42  unsigned char c;
43  const uint8_t *ptr = p->buf;
44  int i;
45 
46  if (AV_RB24(ptr) == 0xEFBBBF)
47  ptr += 3; /* skip UTF-8 BOM */
48 
49  for (i=0; i<3; i++) {
50  if (sscanf(ptr, "{%*d}{}%c", &c) != 1 &&
51  sscanf(ptr, "{%*d}{%*d}%c", &c) != 1 &&
52  sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
53  return 0;
54  ptr += ff_subtitles_next_line(ptr);
55  }
56  return AVPROBE_SCORE_MAX;
57 }
58 
59 static int64_t get_pts(const char *buf)
60 {
61  int frame;
62  char c;
63 
64  if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
65  return frame;
66  return AV_NOPTS_VALUE;
67 }
68 
69 static int64_t get_duration(const char *buf)
70 {
72 
73  if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)
74  return frame_end - (int64_t)frame_start;
75  return -1;
76 }
77 
78 static const char *bom = "\xEF\xBB\xBF";
79 
81 {
82  AVRational pts_info = (AVRational){ 2997, 125 }; /* default: 23.976 fps */
83  MicroDVDContext *microdvd = s->priv_data;
85  int i = 0, ret;
86  char line_buf[MAX_LINESIZE];
87  int has_real_fps = 0;
88 
89  if (!st)
90  return AVERROR(ENOMEM);
91 
92  while (!avio_feof(s->pb)) {
93  char *p;
94  AVPacket *sub;
95  int64_t pos = avio_tell(s->pb);
96  int len = ff_get_line(s->pb, line_buf, sizeof(line_buf));
97  char *line = line_buf;
98  int64_t pts;
99 
100  if (!strncmp(line, bom, 3))
101  line += 3;
102  p = line;
103 
104  if (!len)
105  break;
106  line[strcspn(line, "\r\n")] = 0;
107  if (!*p)
108  continue;
109  if (i++ < 3) {
110  int frame;
111  double fps;
112  char c;
113 
114  if ((sscanf(line, "{%d}{}%6lf", &frame, &fps) == 2 ||
115  sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)
116  && frame <= 1 && fps > 3 && fps < 100) {
117  pts_info = av_d2q(fps, 100000);
118  has_real_fps = 1;
119  continue;
120  }
121  if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
122  int size = strlen(line + 11);
124  if (ret < 0)
125  return ret;
126  memcpy(st->codecpar->extradata, line + 11, size);
127  continue;
128  }
129  }
130 #define SKIP_FRAME_ID \
131  p = strchr(p, '}'); \
132  if (!p) { \
133  av_log(s, AV_LOG_WARNING, "Invalid event \"%s\"" \
134  " at line %d\n", line, i); \
135  continue; \
136  } \
137  p++
140  if (!*p)
141  continue;
142  pts = get_pts(line);
143  if (pts == AV_NOPTS_VALUE)
144  continue;
145  sub = ff_subtitles_queue_insert(&microdvd->q, p, strlen(p), 0);
146  if (!sub)
147  return AVERROR(ENOMEM);
148  sub->pos = pos;
149  sub->pts = pts;
150  sub->duration = get_duration(line);
151  }
152  ff_subtitles_queue_finalize(s, &microdvd->q);
153  if (has_real_fps) {
154  /* export the FPS info only if set in the file */
155  microdvd->frame_rate = pts_info;
156  } else if (microdvd->frame_rate.num) {
157  /* fallback on user specified frame rate */
158  pts_info = microdvd->frame_rate;
159  }
160  avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);
163  return 0;
164 }
165 
167 {
168  MicroDVDContext *microdvd = s->priv_data;
169  return ff_subtitles_queue_read_packet(&microdvd->q, pkt);
170 }
171 
172 static int microdvd_read_seek(AVFormatContext *s, int stream_index,
173  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
174 {
175  MicroDVDContext *microdvd = s->priv_data;
176  return ff_subtitles_queue_seek(&microdvd->q, s, stream_index,
177  min_ts, ts, max_ts, flags);
178 }
179 
181 {
182  MicroDVDContext *microdvd = s->priv_data;
183  ff_subtitles_queue_clean(&microdvd->q);
184  return 0;
185 }
186 
187 
188 #define OFFSET(x) offsetof(MicroDVDContext, x)
189 #define SD AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM
190 static const AVOption microdvd_options[] = {
191  { "subfps", "set the movie frame rate fallback", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, SD },
192  { NULL }
193 };
194 
195 static const AVClass microdvd_class = {
196  .class_name = "microdvddec",
197  .item_name = av_default_item_name,
198  .option = microdvd_options,
199  .version = LIBAVUTIL_VERSION_INT,
200 };
201 
203  .p.name = "microdvd",
204  .p.long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
205  .p.priv_class = &microdvd_class,
206  .priv_data_size = sizeof(MicroDVDContext),
207  .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,
211  .read_seek2 = microdvd_read_seek,
213 };
SD
#define SD
Definition: microdvddec.c:189
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:69
microdvd_probe
static int microdvd_probe(const AVProbeData *p)
Definition: microdvddec.c:40
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
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:51
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const struct AVCodec *c)
Add a new stream to a media file.
AVOption
AVOption.
Definition: opt.h:357
MicroDVDContext
Definition: microdvddec.c:33
microdvd_options
static const AVOption microdvd_options[]
Definition: microdvddec.c:190
AVPacket::duration
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: packet.h:542
get_pts
static int64_t get_pts(const char *buf)
Definition: microdvddec.c:59
AV_OPT_TYPE_RATIONAL
@ AV_OPT_TYPE_RATIONAL
Definition: opt.h:250
microdvd_read_packet
static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: microdvddec.c:166
microdvd_class
static const AVClass microdvd_class
Definition: microdvddec.c:195
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:463
MicroDVDContext::q
FFDemuxSubtitlesQueue q
Definition: microdvddec.c:35
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: avformat.c:853
read_close
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:143
avio_tell
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:494
pts
static int64_t pts
Definition: transcode_aac.c:644
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:172
AVRational::num
int num
Numerator.
Definition: rational.h:59
frame_end
static int64_t frame_end(const SyncQueue *sq, SyncQueueFrame frame, int nb_samples)
Compute the end timestamp of a frame.
Definition: sync_queue.c:128
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:269
frame_start
static int frame_start(MpegEncContext *s)
Definition: mpegvideo_enc.c:1708
pkt
AVPacket * pkt
Definition: movenc.c:60
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_read_callback.c:42
OFFSET
#define OFFSET(x)
Definition: microdvddec.c:188
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:198
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:553
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:453
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:230
FF_INFMT_FLAG_INIT_CLEANUP
#define FF_INFMT_FLAG_INIT_CLEANUP
For an FFInputFormat with this flag set read_close() needs to be called by the caller upon read_heade...
Definition: demux.h:35
AVFormatContext
Format I/O context.
Definition: avformat.h:1255
internal.h
MicroDVDContext::frame_rate
AVRational frame_rate
Definition: microdvddec.c:36
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:766
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:550
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
NULL
#define NULL
Definition: coverity.c:32
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:237
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:451
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:30
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:94
microdvd_read_header
static int microdvd_read_header(AVFormatContext *s)
Definition: microdvddec.c:80
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:212
FFDemuxSubtitlesQueue
Definition: subtitles.h:103
microdvd_read_close
static int microdvd_read_close(AVFormatContext *s)
Definition: microdvddec.c:180
FFInputFormat::p
AVInputFormat p
The public AVInputFormat.
Definition: demux.h:41
ff_subtitles_queue_clean
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:321
line
Definition: graph2dot.c:48
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:517
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:769
demux.h
len
int len
Definition: vorbis_enc_data.h:426
SKIP_FRAME_ID
#define SKIP_FRAME_ID
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:743
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:71
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:414
avformat.h
subtitles.h
AVRational::den
int den
Denominator.
Definition: rational.h:60
ff_microdvd_demuxer
const FFInputFormat ff_microdvd_demuxer
Definition: microdvddec.c:202
AV_CODEC_ID_MICRODVD
@ AV_CODEC_ID_MICRODVD
Definition: codec_id.h:559
read_probe
static int read_probe(const AVProbeData *p)
Definition: cdg.c:30
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:55
AVPacket
This structure stores compressed data.
Definition: packet.h:501
AVPacket::pos
int64_t pos
byte position in stream, -1 if unknown
Definition: packet.h:544
FFInputFormat
Definition: demux.h:37
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:474
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:205
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:78
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:227
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:346
get_duration
static int64_t get_duration(const char *buf)
Definition: microdvddec.c:69