path: root/libavcodec/samidec.c (plain)
blob: 16f3f58c1cfeb7fba0bdf91d4ba0ba263901a543

1	/*
2	* Copyright (c) 2012 Clément Bœsch
3	*
4	* This file is part of FFmpeg.
5	*
6	* FFmpeg is free software; you can redistribute it and/or
7	* modify it under the terms of the GNU Lesser General Public
8	* License as published by the Free Software Foundation; either
9	* version 2.1 of the License, or (at your option) any later version.
10	*
11	* FFmpeg is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14	* Lesser General Public License for more details.
15	*
16	* You should have received a copy of the GNU Lesser General Public
17	* License along with FFmpeg; if not, write to the Free Software
18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19	*/
20
21	/**
22	* @file
23	* SAMI subtitle decoder
24	* @see http://msdn.microsoft.com/en-us/library/ms971327.aspx
25	*/
26
27	#include "ass.h"
28	#include "libavutil/avstring.h"
29	#include "libavutil/bprint.h"
30	#include "htmlsubtitles.h"
31
32	typedef struct {
33	AVBPrint source;
34	AVBPrint content;
35	AVBPrint encoded_source;
36	AVBPrint encoded_content;
37	AVBPrint full;
38	int readorder;
39	} SAMIContext;
40
41	static int sami_paragraph_to_ass(AVCodecContext *avctx, const char *src)
42	{
43	SAMIContext *sami = avctx->priv_data;
44	int ret = 0;
45	char *tag = NULL;
46	char *dupsrc = av_strdup(src);
47	char *p = dupsrc;
48	AVBPrint *dst_content = &sami->encoded_content;
49	AVBPrint *dst_source = &sami->encoded_source;
50
51	av_bprint_clear(&sami->encoded_content);
52	av_bprint_clear(&sami->content);
53	av_bprint_clear(&sami->encoded_source);
54	for (;;) {
55	char *saveptr = NULL;
56	int prev_chr_is_space = 0;
57	AVBPrint *dst = &sami->content;
58
59	/* parse & extract paragraph tag */
60	p = av_stristr(p, "<P");
61	if (!p)
62	break;
63	if (p[2] != '>' && !av_isspace(p[2])) { // avoid confusion with tags such as <PRE>
64	p++;
65	continue;
66	}
67	if (dst->len) // add a separator with the previous paragraph if there was one
68	av_bprintf(dst, "\\N");
69	tag = av_strtok(p, ">", &saveptr);
70	if (!tag || !saveptr)
71	break;
72	p = saveptr;
73
74	/* check if the current paragraph is the "source" (speaker name) */
75	if (av_stristr(tag, "ID=Source") || av_stristr(tag, "ID=\"Source\"")) {
76	dst = &sami->source;
77	av_bprint_clear(dst);
78	}
79
80	/* if empty event -> skip subtitle */
81	while (av_isspace(*p))
82	p++;
83	if (!strncmp(p, "&nbsp;", 6)) {
84	ret = -1;
85	goto end;
86	}
87
88	/* extract the text, stripping most of the tags */
89	while (*p) {
90	if (*p == '<') {
91	if (!av_strncasecmp(p, "<P", 2) && (p[2] == '>' || av_isspace(p[2])))
92	break;
93	}
94	if (!av_strncasecmp(p, "<BR", 3)) {
95	av_bprintf(dst, "\\N");
96	p++;
97	while (*p && *p != '>')
98	p++;
99	if (!*p)
100	break;
101	if (*p == '>')
102	p++;
103	continue;
104	}
105	if (!av_isspace(*p))
106	av_bprint_chars(dst, *p, 1);
107	else if (!prev_chr_is_space)
108	av_bprint_chars(dst, ' ', 1);
109	prev_chr_is_space = av_isspace(*p);
110	p++;
111	}
112	}
113
114	av_bprint_clear(&sami->full);
115	if (sami->source.len) {
116	ff_htmlmarkup_to_ass(avctx, dst_source, sami->source.str);
117	av_bprintf(&sami->full, "{\\i1}%s{\\i0}\\N", sami->encoded_source.str);
118	}
119	ff_htmlmarkup_to_ass(avctx, dst_content, sami->content.str);
120	av_bprintf(&sami->full, "%s", sami->encoded_content.str);
121
122	end:
123	av_free(dupsrc);
124	return ret;
125	}
126
127	static int sami_decode_frame(AVCodecContext *avctx,
128	void *data, int *got_sub_ptr, AVPacket *avpkt)
129	{
130	AVSubtitle *sub = data;
131	const char *ptr = avpkt->data;
132	SAMIContext *sami = avctx->priv_data;
133
134	if (ptr && avpkt->size > 0 && !sami_paragraph_to_ass(avctx, ptr)) {
135	// TODO: pass escaped sami->encoded_source.str as source
136	int ret = ff_ass_add_rect(sub, sami->full.str, sami->readorder++, 0, NULL, NULL);
137	if (ret < 0)
138	return ret;
139	}
140	*got_sub_ptr = sub->num_rects > 0;
141	return avpkt->size;
142	}
143
144	static av_cold int sami_init(AVCodecContext *avctx)
145	{
146	SAMIContext *sami = avctx->priv_data;
147	av_bprint_init(&sami->source, 0, 2048);
148	av_bprint_init(&sami->content, 0, 2048);
149	av_bprint_init(&sami->encoded_source, 0, 2048);
150	av_bprint_init(&sami->encoded_content, 0, 2048);
151	av_bprint_init(&sami->full, 0, 2048);
152	return ff_ass_subtitle_header_default(avctx);
153	}
154
155	static av_cold int sami_close(AVCodecContext *avctx)
156	{
157	SAMIContext *sami = avctx->priv_data;
158	av_bprint_finalize(&sami->source, NULL);
159	av_bprint_finalize(&sami->content, NULL);
160	av_bprint_finalize(&sami->encoded_source, NULL);
161	av_bprint_finalize(&sami->encoded_content, NULL);
162	av_bprint_finalize(&sami->full, NULL);
163	return 0;
164	}
165
166	static void sami_flush(AVCodecContext *avctx)
167	{
168	SAMIContext *sami = avctx->priv_data;
169	if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
170	sami->readorder = 0;
171	}
172
173	AVCodec ff_sami_decoder = {
174	.name = "sami",
175	.long_name = NULL_IF_CONFIG_SMALL("SAMI subtitle"),
176	.type = AVMEDIA_TYPE_SUBTITLE,
177	.id = AV_CODEC_ID_SAMI,
178	.priv_data_size = sizeof(SAMIContext),
179	.init = sami_init,
180	.close = sami_close,
181	.decode = sami_decode_frame,
182	.flush = sami_flush,
183	};
184