FFmpeg
sccdec.c
Go to the documentation of this file.
1 /*
2  * SCC subtitle demuxer
3  * Copyright (c) 2017 Paul B Mahol
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 #include "avformat.h"
23 #include "internal.h"
24 #include "subtitles.h"
25 #include "libavutil/bprint.h"
26 #include "libavutil/intreadwrite.h"
27 
28 typedef struct SCCContext {
30 } SCCContext;
31 
32 static int scc_probe(const AVProbeData *p)
33 {
34  char buf[18];
35  FFTextReader tr;
36 
37  ff_text_init_buf(&tr, p->buf, p->buf_size);
38 
39  while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
40  ff_text_r8(&tr);
41 
42  ff_text_read(&tr, buf, sizeof(buf));
43 
44  if (!memcmp(buf, "Scenarist_SCC V1.0", 18))
45  return AVPROBE_SCORE_MAX;
46 
47  return 0;
48 }
49 
50 static int convert(uint8_t x)
51 {
52  if (x >= 'a')
53  x -= 87;
54  else if (x >= 'A')
55  x -= 55;
56  else
57  x -= '0';
58  return x;
59 }
60 
62 {
63  SCCContext *scc = s->priv_data;
65  char line[4096], line2[4096];
66  int count = 0, ret = 0;
67  ptrdiff_t len2, len;
68  uint8_t out[4096];
69  FFTextReader tr;
70 
71  ff_text_init_avio(s, &tr, s->pb);
72 
73  if (!st)
74  return AVERROR(ENOMEM);
75  avpriv_set_pts_info(st, 64, 1, 1000);
78 
79  while (!ff_text_eof(&tr)) {
80  const int64_t pos = ff_text_pos(&tr);
81  char *saveptr = NULL, *lline;
82  int hh1, mm1, ss1, fs1, i;
83  int hh2, mm2, ss2, fs2;
84  int64_t ts_start, ts_end;
85  AVPacket *sub;
86 
87  if (count == 0) {
88  while (!ff_text_eof(&tr)) {
89  len = ff_subtitles_read_line(&tr, line, sizeof(line));
90  if (len > 13)
91  break;
92  }
93  }
94 
95  if (!strncmp(line, "Scenarist_SCC V1.0", 18))
96  continue;
97  if (sscanf(line, "%d:%d:%d%*[:;]%d", &hh1, &mm1, &ss1, &fs1) != 4)
98  continue;
99 
100  ts_start = (hh1 * 3600LL + mm1 * 60LL + ss1) * 1000LL + fs1 * 33;
101 
102  while (!ff_text_eof(&tr)) {
103  len2 = ff_subtitles_read_line(&tr, line2, sizeof(line2));
104  if (len2 > 13)
105  break;
106  }
107  if (sscanf(line2, "%d:%d:%d%*[:;]%d", &hh2, &mm2, &ss2, &fs2) != 4)
108  continue;
109 
110  ts_end = (hh2 * 3600LL + mm2 * 60LL + ss2) * 1000LL + fs2 * 33;
111  count++;
112 
113 try_again:
114  lline = (char *)&line;
115  lline += 12;
116 
117  for (i = 0; i < 4095; i += 3) {
118  char *ptr = av_strtok(lline, " ", &saveptr);
119  char c1, c2, c3, c4;
120 
121  if (!ptr)
122  break;
123 
124  if (sscanf(ptr, "%c%c%c%c", &c1, &c2, &c3, &c4) != 4)
125  break;
126 
127  lline = NULL;
128  out[i+0] = 0xfc;
129  out[i+1] = convert(c2) | (convert(c1) << 4);
130  out[i+2] = convert(c4) | (convert(c3) << 4);
131  }
132  out[i] = 0;
133 
134  sub = ff_subtitles_queue_insert(&scc->q, out, i, 0);
135  if (!sub)
136  return AVERROR(ENOMEM);
137 
138  sub->pos = pos;
139  sub->pts = ts_start;
140  sub->duration = FFMAX(1200, ts_end - ts_start);
141  memmove(line, line2, sizeof(line));
142  line2[0] = 0;
143  FFSWAP(ptrdiff_t, len, len2);
144  }
145 
146  if (line[0])
147  goto try_again;
148 
149  ff_subtitles_queue_finalize(s, &scc->q);
150 
151  return ret;
152 }
153 
155 {
156  SCCContext *scc = s->priv_data;
157  return ff_subtitles_queue_read_packet(&scc->q, pkt);
158 }
159 
160 static int scc_read_seek(AVFormatContext *s, int stream_index,
161  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
162 {
163  SCCContext *scc = s->priv_data;
164  return ff_subtitles_queue_seek(&scc->q, s, stream_index,
165  min_ts, ts, max_ts, flags);
166 }
167 
169 {
170  SCCContext *scc = s->priv_data;
172  return 0;
173 }
174 
176  .name = "scc",
177  .long_name = NULL_IF_CONFIG_SMALL("Scenarist Closed Captions"),
178  .priv_data_size = sizeof(SCCContext),
182  .read_seek2 = scc_read_seek,
184  .extensions = "scc",
185 };
#define NULL
Definition: coverity.c:32
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
static int scc_read_close(AVFormatContext *s)
Definition: sccdec.c:168
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3957
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
Remove and destroy all the subtitles packets.
Definition: subtitles.c:297
int ff_text_peek_r8(FFTextReader *r)
Like ff_text_r8(), but don&#39;t remove the byte from the buffer.
Definition: subtitles.c:97
static AVPacket pkt
Format I/O context.
Definition: avformat.h:1358
static int scc_read_header(AVFormatContext *s)
Definition: sccdec.c:61
uint8_t
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
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4465
static const uint64_t c1
Definition: murmur3.c:49
FFDemuxSubtitlesQueue q
Definition: sccdec.c:29
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:145
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
int ff_text_eof(FFTextReader *r)
Return non-zero if EOF was reached.
Definition: subtitles.c:92
ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size)
Read a line of text.
Definition: subtitles.c:406
#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
GLsizei count
Definition: opengl_enc.c:108
#define FFMAX(a, b)
Definition: common.h:94
void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb)
Initialize the FFTextReader from the given AVIOContext.
Definition: subtitles.c:27
static int scc_probe(const AVProbeData *p)
Definition: sccdec.c:32
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:449
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:448
int64_t ff_text_pos(FFTextReader *r)
Return the byte position of the next byte returned by ff_text_r8().
Definition: subtitles.c:60
AVInputFormat ff_scc_demuxer
Definition: sccdec.c:175
static int scc_read_seek(AVFormatContext *s, int stream_index, int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
Definition: sccdec.c:160
#define s(width, name)
Definition: cbs_vp9.c:257
void ff_text_read(FFTextReader *r, char *buf, size_t size)
Read the given number of bytes (in UTF-8).
Definition: subtitles.c:86
static int convert(uint8_t x)
Definition: sccdec.c:50
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:530
int ff_text_r8(FFTextReader *r)
Return the next byte.
Definition: subtitles.c:65
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
AVIOContext * pb
I/O context.
Definition: avformat.h:1400
void * buf
Definition: avisynth_c.h:766
This structure contains the data a format has to probe a file.
Definition: avformat.h:446
#define flags(name, subs,...)
Definition: cbs_av1.c:561
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
char * av_strtok(char *s, const char *delim, char **saveptr)
Split the string into several tokens which can be accessed by successive calls to av_strtok()...
Definition: avstring.c:184
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:458
Main libavformat public API header.
void ff_text_init_buf(FFTextReader *r, void *buf, size_t size)
Similar to ff_text_init_avio(), but sets it up to read from a bounded buffer.
Definition: subtitles.c:53
static const uint64_t c2
Definition: murmur3.c:50
int len
void * priv_data
Format private data.
Definition: avformat.h:1386
FILE * out
Definition: movenc.c:54
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
static int scc_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: sccdec.c:154
#define FFSWAP(type, a, b)
Definition: common.h:99
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
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