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