path: root/libavformat/assdec.c (plain)
blob: d89c14e5b8e353c70a0406ec2625e3b22a5891ce

1	/*
2	* SSA/ASS demuxer
3	* Copyright (c) 2008 Michael Niedermayer
4	* Copyright (c) 2014 Clément Bœsch
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 <stdint.h>
24
25	#include "avformat.h"
26	#include "internal.h"
27	#include "subtitles.h"
28	#include "libavcodec/internal.h"
29	#include "libavutil/bprint.h"
30
31	typedef struct ASSContext {
32	FFDemuxSubtitlesQueue q;
33	unsigned readorder;
34	} ASSContext;
35
36	static int ass_probe(AVProbeData *p)
37	{
38	char buf[13];
39	FFTextReader tr;
40	ff_text_init_buf(&tr, p->buf, p->buf_size);
41
42	while (ff_text_peek_r8(&tr) == '\r' || ff_text_peek_r8(&tr) == '\n')
43	ff_text_r8(&tr);
44
45	ff_text_read(&tr, buf, sizeof(buf));
46
47	if (!memcmp(buf, "[Script Info]", 13))
48	return AVPROBE_SCORE_MAX;
49
50	return 0;
51	}
52
53	static int ass_read_close(AVFormatContext *s)
54	{
55	ASSContext *ass = s->priv_data;
56	ff_subtitles_queue_clean(&ass->q);
57	return 0;
58	}
59
60	static int read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p,
61	int64_t *start, int *duration)
62	{
63	int pos = 0;
64	int64_t end;
65	int hh1, mm1, ss1, ms1;
66	int hh2, mm2, ss2, ms2;
67
68	if (sscanf(p, "Dialogue: %*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d,%n",
69	&hh1, &mm1, &ss1, &ms1,
70	&hh2, &mm2, &ss2, &ms2, &pos) >= 8 && pos > 0) {
71
72	/* This is not part of the sscanf itself in order to handle an actual
73	* number (which would be the Layer) or the form "Marked=N" (which is
74	* the old SSA field, now replaced by Layer, and will lead to Layer
75	* being 0 here). */
76	const int layer = atoi(p + 10);
77
78	end = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
79	*start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
80	*duration = end - *start;
81
82	av_bprint_clear(dst);
83	av_bprintf(dst, "%u,%d,%s", ass->readorder++, layer, p + pos);
84
85	/* right strip the buffer */
86	while (dst->len > 0 &&
87	dst->str[dst->len - 1] == '\r' ||
88	dst->str[dst->len - 1] == '\n')
89	dst->str[--dst->len] = 0;
90	return 0;
91	}
92	return -1;
93	}
94
95	static int64_t get_line(AVBPrint *buf, FFTextReader *tr)
96	{
97	int64_t pos = ff_text_pos(tr);
98
99	av_bprint_clear(buf);
100	for (;;) {
101	char c = ff_text_r8(tr);
102	if (!c)
103	break;
104	av_bprint_chars(buf, c, 1);
105	if (c == '\n')
106	break;
107	}
108	return pos;
109	}
110
111	static int ass_read_header(AVFormatContext *s)
112	{
113	ASSContext *ass = s->priv_data;
114	AVBPrint header, line, rline;
115	int res = 0;
116	AVStream *st;
117	FFTextReader tr;
118	ff_text_init_avio(s, &tr, s->pb);
119
120	st = avformat_new_stream(s, NULL);
121	if (!st)
122	return AVERROR(ENOMEM);
123	avpriv_set_pts_info(st, 64, 1, 100);
124	st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
125	st->codecpar->codec_id = AV_CODEC_ID_ASS;
126
127	av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
128	av_bprint_init(&line, 0, AV_BPRINT_SIZE_UNLIMITED);
129	av_bprint_init(&rline, 0, AV_BPRINT_SIZE_UNLIMITED);
130
131	ass->q.keep_duplicates = 1;
132
133	for (;;) {
134	int64_t pos = get_line(&line, &tr);
135	int64_t ts_start = AV_NOPTS_VALUE;
136	int duration = -1;
137	AVPacket *sub;
138
139	if (!line.str[0]) // EOF
140	break;
141
142	if (read_dialogue(ass, &rline, line.str, &ts_start, &duration) < 0) {
143	av_bprintf(&header, "%s", line.str);
144	continue;
145	}
146	sub = ff_subtitles_queue_insert(&ass->q, rline.str, rline.len, 0);
147	if (!sub) {
148	res = AVERROR(ENOMEM);
149	goto end;
150	}
151	sub->pos = pos;
152	sub->pts = ts_start;
153	sub->duration = duration;
154	}
155
156	res = ff_bprint_to_codecpar_extradata(st->codecpar, &header);
157	if (res < 0)
158	goto end;
159
160	ff_subtitles_queue_finalize(s, &ass->q);
161
162	end:
163	av_bprint_finalize(&header, NULL);
164	av_bprint_finalize(&line, NULL);
165	av_bprint_finalize(&rline, NULL);
166	return res;
167	}
168
169	static int ass_read_packet(AVFormatContext *s, AVPacket *pkt)
170	{
171	ASSContext *ass = s->priv_data;
172	return ff_subtitles_queue_read_packet(&ass->q, pkt);
173	}
174
175	static int ass_read_seek(AVFormatContext *s, int stream_index,
176	int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
177	{
178	ASSContext *ass = s->priv_data;
179	return ff_subtitles_queue_seek(&ass->q, s, stream_index,
180	min_ts, ts, max_ts, flags);
181	}
182
183	AVInputFormat ff_ass_demuxer = {
184	.name = "ass",
185	.long_name = NULL_IF_CONFIG_SMALL("SSA (SubStation Alpha) subtitle"),
186	.priv_data_size = sizeof(ASSContext),
187	.read_probe = ass_probe,
188	.read_header = ass_read_header,
189	.read_packet = ass_read_packet,
190	.read_close = ass_read_close,
191	.read_seek2 = ass_read_seek,
192	};
193