FFmpeg: libavformat/srtenc.c Source File

FFmpeg
srtenc.c
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1 /*
2  * SubRip subtitle muxer
3  * Copyright (c) 2012 Nicolas George <nicolas.george@normalesup.org>
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 "libavutil/log.h"
25 #include "libavutil/intreadwrite.h"
26 
27 /* TODO: add options for:
28  - character encoding;
29  - LF / CRLF;
30  - byte order mark.
31  */
32 
33 typedef struct SRTContext{
34   unsigned index;
35 } SRTContext;
36 
37  static int srt_write_header(AVFormatContext *avf)
38 {
39  SRTContext *srt = avf->priv_data;
40 
41  if (avf->nb_streams != 1 ||
42  avf->streams[0]->codec->codec_type != AVMEDIA_TYPE_SUBTITLE) {
43  av_log(avf, AV_LOG_ERROR,
44  "SRT supports only a single subtitles stream.\n");
45  return AVERROR(EINVAL);
46  }
47  if (avf->streams[0]->codec->codec_id != AV_CODEC_ID_TEXT &&
48  avf->streams[0]->codec->codec_id != AV_CODEC_ID_SUBRIP) {
49  av_log(avf, AV_LOG_ERROR,
50  "Unsupported subtitles codec: %s\n",
51  avcodec_get_name(avf->streams[0]->codec->codec_id));
52  return AVERROR(EINVAL);
53  }
54  avpriv_set_pts_info(avf->streams[0], 64, 1, 1000);
55  srt->index = 1;
56  return 0;
57 }
58 
59  static int srt_write_packet(AVFormatContext *avf, AVPacket *pkt)
60 {
61  SRTContext *srt = avf->priv_data;
62 
63  int64_t s = pkt->pts, e, d = pkt->duration;
64  int size, x1 = -1, y1 = -1, x2 = -1, y2 = -1;
65  const uint8_t *p;
66 
67  p = av_packet_get_side_data(pkt, AV_PKT_DATA_SUBTITLE_POSITION, &size);
68  if (p && size == 16) {
69  x1 = AV_RL32(p );
70  y1 = AV_RL32(p + 4);
71  x2 = AV_RL32(p + 8);
72  y2 = AV_RL32(p + 12);
73  }
74 
75 #if FF_API_CONVERGENCE_DURATION
76 FF_DISABLE_DEPRECATION_WARNINGS
77  if (d <= 0)
78  /* For backward compatibility, fallback to convergence_duration. */
79  d = pkt->convergence_duration;
80 FF_ENABLE_DEPRECATION_WARNINGS
81 #endif
82  if (s == AV_NOPTS_VALUE || d < 0) {
83  av_log(avf, AV_LOG_WARNING,
84  "Insufficient timestamps in event number %d.\n", srt->index);
85  return 0;
86  }
87  e = s + d;
88  avio_printf(avf->pb, "%d\n%02d:%02d:%02d,%03d --> %02d:%02d:%02d,%03d",
89  srt->index,
90  (int)(s / 3600000), (int)(s / 60000) % 60,
91  (int)(s / 1000) % 60, (int)(s % 1000),
92  (int)(e / 3600000), (int)(e / 60000) % 60,
93  (int)(e / 1000) % 60, (int)(e % 1000));
94  if (p)
95  avio_printf(avf->pb, " X1:%03d X2:%03d Y1:%03d Y2:%03d",
96  x1, x2, y1, y2);
97  avio_printf(avf->pb, "\n");
98 
99  avio_write(avf->pb, pkt->data, pkt->size);
100  avio_write(avf->pb, "\n\n", 2);
101  srt->index++;
102  return 0;
103 }
104 
105  AVOutputFormat ff_srt_muxer = {
106  .name = "srt",
107  .long_name = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
108  .mime_type = "application/x-subrip",
109  .extensions = "srt",
110  .priv_data_size = sizeof(SRTContext),
111  .write_header = srt_write_header,
112  .write_packet = srt_write_packet,
113  .flags = AVFMT_VARIABLE_FPS | AVFMT_TS_NONSTRICT,
114  .subtitle_codec = AV_CODEC_ID_SUBRIP,
115 };
s
const char * s
Definition: avisynth_c.h:631
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
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:4149
AV_PKT_DATA_SUBTITLE_POSITION
Subtitle event position.
Definition: avcodec.h:1379
srt_write_header
static int srt_write_header(AVFormatContext *avf)
Definition: srtenc.c:37
AVPacket::size
int size
Definition: avcodec.h:1468
SRTContext
Definition: srtenc.c:32
pkt
static AVPacket pkt
Definition: demuxing_decoding.c:54
AVFMT_TS_NONSTRICT
#define AVFMT_TS_NONSTRICT
Format does not require strictly increasing timestamps, but they must still be monotonic.
Definition: avformat.h:495
srt_write_packet
static int srt_write_packet(AVFormatContext *avf, AVPacket *pkt)
Definition: srtenc.c:59
AVFormatContext
Format I/O context.
Definition: avformat.h:1314
uint8_t
uint8_t
Definition: audio_convert.c:194
AVPacket::duration
int64_t duration
Duration of this packet in AVStream->time_base units, 0 if unknown.
Definition: avcodec.h:1485
AVFormatContext::streams
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1382
AVPacket::data
uint8_t * data
Definition: avcodec.h:1467
size
ptrdiff_t size
Definition: opengl_enc.c:101
avio_write
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:182
AV_CODEC_ID_SUBRIP
Definition: avcodec.h:524
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
AVERROR
#define AVERROR(e)
Definition: error.h:43
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:176
AVStream::codec
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:896
AVFormatContext::nb_streams
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1370
SRTContext::index
unsigned index
Definition: srtenc.c:34
AVOutputFormat::name
const char * name
Definition: avformat.h:523
avcodec_get_name
const char * avcodec_get_name(enum AVCodecID id)
Get the name of a codec.
Definition: utils.c:2648
AVCodecContext::codec_type
enum AVMediaType codec_type
Definition: avcodec.h:1540
AVCodecContext::codec_id
enum AVCodecID codec_id
Definition: avcodec.h:1549
AVFormatContext::pb
AVIOContext * pb
I/O context.
Definition: avformat.h:1356
flags
static int flags
Definition: cpu.c:47
avformat.h
Main libavformat public API header.
AVPacket::convergence_duration
attribute_deprecated int64_t convergence_duration
Definition: avcodec.h:1496
FF_DISABLE_DEPRECATION_WARNINGS
#define FF_DISABLE_DEPRECATION_WARNINGS
Definition: internal.h:80
AV_CODEC_ID_TEXT
raw UTF-8 text
Definition: avcodec.h:508
AVFMT_VARIABLE_FPS
#define AVFMT_VARIABLE_FPS
Format allows variable fps.
Definition: avformat.h:488
FF_ENABLE_DEPRECATION_WARNINGS
#define FF_ENABLE_DEPRECATION_WARNINGS
Definition: internal.h:81
AVFormatContext::priv_data
void * priv_data
Format private data.
Definition: avformat.h:1342
write_header
static void write_header(FFV1Context *f)
Definition: ffv1enc.c:497
ff_srt_muxer
AVOutputFormat ff_srt_muxer
Definition: srtenc.c:105
av_packet_get_side_data
uint8_t * av_packet_get_side_data(AVPacket *pkt, enum AVPacketSideDataType type, int *size)
Get side information from packet.
Definition: avpacket.c:320
AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:196
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:87
AVPacket
This structure stores compressed data.
Definition: avcodec.h:1444
write_packet
static int write_packet(AVFormatContext *s1, AVPacket *pkt)
Definition: v4l2enc.c:86
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1460
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:240
avio_printf
int avio_printf(AVIOContext *s, const char *fmt,...) av_printf_format(2
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