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