FFmpeg
assenc.c
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1 /*
2  * SSA/ASS encoder
3  * Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.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 <string.h>
23 
24 #include "avcodec.h"
25 #include "ass.h"
26 #include "libavutil/avstring.h"
27 #include "libavutil/internal.h"
28 #include "libavutil/mem.h"
29 
30 typedef struct {
31  int id; ///< current event id, ReadOrder field
33 
35 {
36  avctx->extradata = av_malloc(avctx->subtitle_header_size + 1);
37  if (!avctx->extradata)
38  return AVERROR(ENOMEM);
39  memcpy(avctx->extradata, avctx->subtitle_header, avctx->subtitle_header_size);
40  avctx->extradata_size = avctx->subtitle_header_size;
41  avctx->extradata[avctx->extradata_size] = 0;
42  return 0;
43 }
44 
45 static int ass_encode_frame(AVCodecContext *avctx,
46  unsigned char *buf, int bufsize,
47  const AVSubtitle *sub)
48 {
49  ASSEncodeContext *s = avctx->priv_data;
50  int i, len, total_len = 0;
51 
52  for (i=0; i<sub->num_rects; i++) {
53  char ass_line[2048];
54  const char *ass = sub->rects[i]->ass;
55  long int layer;
56  char *p;
57 
58  if (sub->rects[i]->type != SUBTITLE_ASS) {
59  av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
60  return AVERROR(EINVAL);
61  }
62 
63 #if FF_API_ASS_TIMING
64  if (!strncmp(ass, "Dialogue: ", 10)) {
65  if (i > 0) {
66  av_log(avctx, AV_LOG_ERROR, "ASS encoder supports only one "
67  "ASS rectangle field.\n");
68  return AVERROR_INVALIDDATA;
69  }
70 
71  ass += 10; // skip "Dialogue: "
72  /* parse Layer field. If it's a Marked field, the content
73  * will be "Marked=N" instead of the layer num, so we will
74  * have layer=0, which is fine. */
75  layer = strtol(ass, &p, 10);
76 
77 #define SKIP_ENTRY(ptr) do { \
78  char *sep = strchr(ptr, ','); \
79  if (sep) \
80  ptr = sep + 1; \
81 } while (0)
82 
83  SKIP_ENTRY(p); // skip layer or marked
84  SKIP_ENTRY(p); // skip start timestamp
85  SKIP_ENTRY(p); // skip end timestamp
86  snprintf(ass_line, sizeof(ass_line), "%d,%ld,%s", ++s->id, layer, p);
87  ass_line[strcspn(ass_line, "\r\n")] = 0;
88  ass = ass_line;
89  }
90 #endif
91 
92  len = av_strlcpy(buf+total_len, ass, bufsize-total_len);
93 
94  if (len > bufsize-total_len-1) {
95  av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
96  return AVERROR(EINVAL);
97  }
98 
99  total_len += len;
100  }
101 
102  return total_len;
103 }
104 
105 #if CONFIG_SSA_ENCODER
107  .name = "ssa",
108  .long_name = NULL_IF_CONFIG_SMALL("ASS (Advanced SubStation Alpha) subtitle"),
109  .type = AVMEDIA_TYPE_SUBTITLE,
110  .id = AV_CODEC_ID_ASS,
111  .init = ass_encode_init,
112  .encode_sub = ass_encode_frame,
113  .priv_data_size = sizeof(ASSEncodeContext),
114 };
115 #endif
116 
117 #if CONFIG_ASS_ENCODER
119  .name = "ass",
120  .long_name = NULL_IF_CONFIG_SMALL("ASS (Advanced SubStation Alpha) subtitle"),
121  .type = AVMEDIA_TYPE_SUBTITLE,
122  .id = AV_CODEC_ID_ASS,
123  .init = ass_encode_init,
124  .encode_sub = ass_encode_frame,
125  .priv_data_size = sizeof(ASSEncodeContext),
126 };
127 #endif
AVSubtitle
Definition: avcodec.h:3933
AVCodec
AVCodec.
Definition: avcodec.h:3481
AVMEDIA_TYPE_SUBTITLE
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
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
AVSubtitle::rects
AVSubtitleRect ** rects
Definition: avcodec.h:3938
AVSubtitle::num_rects
unsigned num_rects
Definition: avcodec.h:3937
ff_ssa_encoder
AVCodec ff_ssa_encoder
AVCodecContext::subtitle_header
uint8_t * subtitle_header
Header containing style information for text subtitles.
Definition: avcodec.h:3050
SKIP_ENTRY
#define SKIP_ENTRY(ptr)
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:31
SUBTITLE_ASS
@ SUBTITLE_ASS
Formatted text, the ass field must be set by the decoder and is authoritative.
Definition: avcodec.h:3893
AV_CODEC_ID_ASS
@ AV_CODEC_ID_ASS
Definition: avcodec.h:681
AVSubtitleRect::ass
char * ass
0 terminated ASS/SSA compatible event line.
Definition: avcodec.h:3928
ass.h
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
buf
void * buf
Definition: avisynth_c.h:766
av_cold
#define av_cold
Definition: attributes.h:84
AVCodecContext::extradata_size
int extradata_size
Definition: avcodec.h:1667
s
#define s(width, name)
Definition: cbs_vp9.c:257
ASSEncodeContext
Definition: assenc.c:30
AVCodecContext::subtitle_header_size
int subtitle_header_size
Definition: avcodec.h:3051
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:188
AVSubtitleRect::type
enum AVSubtitleType type
Definition: avcodec.h:3919
ass_encode_frame
static int ass_encode_frame(AVCodecContext *avctx, unsigned char *buf, int bufsize, const AVSubtitle *sub)
Definition: assenc.c:45
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
AVCodecContext::extradata
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:1666
internal.h
ff_ass_encoder
AVCodec ff_ass_encoder
AVCodec::name
const char * name
Name of the codec implementation.
Definition: avcodec.h:3488
len
int len
Definition: vorbis_enc_data.h:452
avcodec.h
AVCodecContext
main external API structure.
Definition: avcodec.h:1565
ass_encode_init
static av_cold int ass_encode_init(AVCodecContext *avctx)
Definition: assenc.c:34
mem.h
ASSEncodeContext::id
int id
current event id, ReadOrder field
Definition: assenc.c:31
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:1592
av_strlcpy
size_t av_strlcpy(char *dst, const char *src, size_t size)
Copy the string src to dst, but no more than size - 1 bytes, and null-terminate dst.
Definition: avstring.c:83
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
avstring.h
snprintf
#define snprintf
Definition: snprintf.h:34