path: root/libavformat/microdvddec.c (plain)
blob: c2f1ac45cda7a029ef45c7315566ff2e514ee565

1	/*
2	* MicroDVD subtitle demuxer
3	* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
4	* Copyright (c) 2012 Clément Bœsch <u pkh me>
5	*
6	* This file is part of FFmpeg.
7	*
8	* FFmpeg is free software; you can redistribute it and/or
9	* modify it under the terms of the GNU Lesser General Public
10	* License as published by the Free Software Foundation; either
11	* version 2.1 of the License, or (at your option) any later version.
12	*
13	* FFmpeg is distributed in the hope that it will be useful,
14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16	* Lesser General Public License for more details.
17	*
18	* You should have received a copy of the GNU Lesser General Public
19	* License along with FFmpeg; if not, write to the Free Software
20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21	*/
22
23	#include "avformat.h"
24	#include "internal.h"
25	#include "subtitles.h"
26	#include "libavutil/intreadwrite.h"
27	#include "libavutil/opt.h"
28
29	#define MAX_LINESIZE 2048
30
31
32	typedef struct {
33	const AVClass *class;
34	FFDemuxSubtitlesQueue q;
35	AVRational frame_rate;
36	} MicroDVDContext;
37
38
39	static int microdvd_probe(AVProbeData *p)
40	{
41	unsigned char c;
42	const uint8_t *ptr = p->buf;
43	int i;
44
45	if (AV_RB24(ptr) == 0xEFBBBF)
46	ptr += 3; /* skip UTF-8 BOM */
47
48	for (i=0; i<3; i++) {
49	if (sscanf(ptr, "{%*d}{}%c", &c) != 1 &&
50	sscanf(ptr, "{%*d}{%*d}%c", &c) != 1 &&
51	sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
52	return 0;
53	ptr += ff_subtitles_next_line(ptr);
54	}
55	return AVPROBE_SCORE_MAX;
56	}
57
58	static int64_t get_pts(const char *buf)
59	{
60	int frame;
61	char c;
62
63	if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
64	return frame;
65	return AV_NOPTS_VALUE;
66	}
67
68	static int get_duration(const char *buf)
69	{
70	int frame_start, frame_end;
71
72	if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)
73	return frame_end - frame_start;
74	return -1;
75	}
76
77	static const char *bom = "\xEF\xBB\xBF";
78
79	static int microdvd_read_header(AVFormatContext *s)
80	{
81	AVRational pts_info = (AVRational){ 2997, 125 }; /* default: 23.976 fps */
82	MicroDVDContext *microdvd = s->priv_data;
83	AVStream *st = avformat_new_stream(s, NULL);
84	int i = 0;
85	char line_buf[MAX_LINESIZE];
86	int has_real_fps = 0;
87
88	if (!st)
89	return AVERROR(ENOMEM);
90
91	while (!avio_feof(s->pb)) {
92	char *p;
93	AVPacket *sub;
94	int64_t pos = avio_tell(s->pb);
95	int len = ff_get_line(s->pb, line_buf, sizeof(line_buf));
96	char *line = line_buf;
97
98	if (!strncmp(line, bom, 3))
99	line += 3;
100	p = line;
101
102	if (!len)
103	break;
104	line[strcspn(line, "\r\n")] = 0;
105	if (i++ < 3) {
106	int frame;
107	double fps;
108	char c;
109
110	if ((sscanf(line, "{%d}{}%6lf", &frame, &fps) == 2 ||
111	sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)
112	&& frame <= 1 && fps > 3 && fps < 100) {
113	pts_info = av_d2q(fps, 100000);
114	has_real_fps = 1;
115	continue;
116	}
117	if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
118	st->codecpar->extradata = av_strdup(line + 11);
119	if (!st->codecpar->extradata)
120	return AVERROR(ENOMEM);
121	st->codecpar->extradata_size = strlen(st->codecpar->extradata) + 1;
122	continue;
123	}
124	}
125	#define SKIP_FRAME_ID \
126	p = strchr(p, '}'); \
127	if (!p) { \
128	av_log(s, AV_LOG_WARNING, "Invalid event \"%s\"" \
129	" at line %d\n", line, i); \
130	continue; \
131	} \
132	p++
133	SKIP_FRAME_ID;
134	SKIP_FRAME_ID;
135	if (!*p)
136	continue;
137	sub = ff_subtitles_queue_insert(&microdvd->q, p, strlen(p), 0);
138	if (!sub)
139	return AVERROR(ENOMEM);
140	sub->pos = pos;
141	sub->pts = get_pts(line);
142	sub->duration = get_duration(line);
143	}
144	ff_subtitles_queue_finalize(s, &microdvd->q);
145	if (has_real_fps) {
146	/* export the FPS info only if set in the file */
147	microdvd->frame_rate = pts_info;
148	} else if (microdvd->frame_rate.num) {
149	/* fallback on user specified frame rate */
150	pts_info = microdvd->frame_rate;
151	}
152	avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);
153	st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
154	st->codecpar->codec_id = AV_CODEC_ID_MICRODVD;
155	return 0;
156	}
157
158	static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
159	{
160	MicroDVDContext *microdvd = s->priv_data;
161	return ff_subtitles_queue_read_packet(&microdvd->q, pkt);
162	}
163
164	static int microdvd_read_seek(AVFormatContext *s, int stream_index,
165	int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
166	{
167	MicroDVDContext *microdvd = s->priv_data;
168	return ff_subtitles_queue_seek(&microdvd->q, s, stream_index,
169	min_ts, ts, max_ts, flags);
170	}
171
172	static int microdvd_read_close(AVFormatContext *s)
173	{
174	MicroDVDContext *microdvd = s->priv_data;
175	ff_subtitles_queue_clean(&microdvd->q);
176	return 0;
177	}
178
179
180	#define OFFSET(x) offsetof(MicroDVDContext, x)
181	#define SD AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM
182	static const AVOption microdvd_options[] = {
183	{ "subfps", "set the movie frame rate fallback", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, SD },
184	{ NULL }
185	};
186
187	static const AVClass microdvd_class = {
188	.class_name = "microdvddec",
189	.item_name = av_default_item_name,
190	.option = microdvd_options,
191	.version = LIBAVUTIL_VERSION_INT,
192	};
193
194	AVInputFormat ff_microdvd_demuxer = {
195	.name = "microdvd",
196	.long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
197	.priv_data_size = sizeof(MicroDVDContext),
198	.read_probe = microdvd_probe,
199	.read_header = microdvd_read_header,
200	.read_packet = microdvd_read_packet,
201	.read_seek2 = microdvd_read_seek,
202	.read_close = microdvd_read_close,
203	.priv_class = &microdvd_class,
204	};
205