path: root/libavcodec/assenc.c (plain)
blob: dc4f0ffa9722032594ea52533d79ee48584c7448

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
32	} ASSEncodeContext;
33
34	static av_cold int ass_encode_init(AVCodecContext *avctx)
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 -1;
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 -1;
97	}
98
99	total_len += len;
100	}
101
102	return total_len;
103	}
104
105	#if CONFIG_SSA_ENCODER
106	AVCodec ff_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
118	AVCodec ff_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
128