path: root/libavcodec/dvbsub_parser.c (plain)
blob: e77b9655cca2377f780ca0b0ede511663275783b

1	/*
2	* DVB subtitle parser for FFmpeg
3	* Copyright (c) 2005 Ian Caulfield
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 <inttypes.h>
23	#include <string.h>
24
25	#include "libavutil/intreadwrite.h"
26	#include "libavutil/mem.h"
27
28	#include "avcodec.h"
29	#include "internal.h"
30
31	/* Parser (mostly) copied from dvdsub.c */
32
33	#define PARSE_BUF_SIZE (65536)
34
35
36	/* parser definition */
37	typedef struct DVBSubParseContext {
38	uint8_t *packet_buf;
39	int packet_start;
40	int packet_index;
41	int in_packet;
42	} DVBSubParseContext;
43
44	static av_cold int dvbsub_parse_init(AVCodecParserContext *s)
45	{
46	DVBSubParseContext *pc = s->priv_data;
47	pc->packet_buf = av_malloc(PARSE_BUF_SIZE);
48
49	return 0;
50	}
51
52	static int dvbsub_parse(AVCodecParserContext *s,
53	AVCodecContext *avctx,
54	const uint8_t **poutbuf, int *poutbuf_size,
55	const uint8_t *buf, int buf_size)
56	{
57	DVBSubParseContext *pc = s->priv_data;
58	uint8_t *p, *p_end;
59	int i, len, buf_pos = 0;
60
61	ff_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
62	s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
63
64	for (i=0; i < buf_size; i++)
65	{
66	ff_dlog(avctx, "%02x ", buf[i]);
67	if (i % 16 == 15)
68	ff_dlog(avctx, "\n");
69	}
70
71	if (i % 16 != 0)
72	ff_dlog(avctx, "\n");
73
74	*poutbuf = NULL;
75	*poutbuf_size = 0;
76
77	s->fetch_timestamp = 1;
78
79	if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
80	{
81	if (pc->packet_index != pc->packet_start)
82	{
83	ff_dlog(avctx, "Discarding %d bytes\n",
84	pc->packet_index - pc->packet_start);
85	}
86
87	pc->packet_start = 0;
88	pc->packet_index = 0;
89
90	if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
91	ff_dlog(avctx, "Bad packet header\n");
92	return -1;
93	}
94
95	buf_pos = 2;
96
97	pc->in_packet = 1;
98	} else {
99	if (pc->packet_start != 0)
100	{
101	if (pc->packet_index != pc->packet_start)
102	{
103	memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
104	pc->packet_index - pc->packet_start);
105
106	pc->packet_index -= pc->packet_start;
107	pc->packet_start = 0;
108	} else {
109	pc->packet_start = 0;
110	pc->packet_index = 0;
111	}
112	}
113	}
114
115	if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
116	return -1;
117
118	/* if not currently in a packet, discard data */
119	if (pc->in_packet == 0)
120	return buf_size;
121
122	memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
123	pc->packet_index += buf_size - buf_pos;
124
125	p = pc->packet_buf;
126	p_end = pc->packet_buf + pc->packet_index;
127
128	while (p < p_end)
129	{
130	if (*p == 0x0f)
131	{
132	if (6 <= p_end - p)
133	{
134	len = AV_RB16(p + 4);
135
136	if (len + 6 <= p_end - p)
137	{
138	*poutbuf_size += len + 6;
139
140	p += len + 6;
141	} else
142	break;
143	} else
144	break;
145	} else if (*p == 0xff) {
146	if (1 < p_end - p)
147	{
148	ff_dlog(avctx, "Junk at end of packet\n");
149	}
150	pc->packet_index = p - pc->packet_buf;
151	pc->in_packet = 0;
152	break;
153	} else {
154	av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
155
156	pc->packet_index = p - pc->packet_buf;
157	pc->in_packet = 0;
158	break;
159	}
160	}
161
162	if (*poutbuf_size > 0)
163	{
164	*poutbuf = pc->packet_buf;
165	pc->packet_start = *poutbuf_size;
166	}
167
168	if (s->pts == AV_NOPTS_VALUE)
169	s->pts = s->last_pts;
170
171	return buf_size;
172	}
173
174	static av_cold void dvbsub_parse_close(AVCodecParserContext *s)
175	{
176	DVBSubParseContext *pc = s->priv_data;
177	av_freep(&pc->packet_buf);
178	}
179
180	AVCodecParser ff_dvbsub_parser = {
181	.codec_ids = { AV_CODEC_ID_DVB_SUBTITLE },
182	.priv_data_size = sizeof(DVBSubParseContext),
183	.parser_init = dvbsub_parse_init,
184	.parser_parse = dvbsub_parse,
185	.parser_close = dvbsub_parse_close,
186	};
187