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
dvbsub_parse_init(AVCodecParserContext * s)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
dvbsub_parse(AVCodecParserContext * s,AVCodecContext * avctx,const uint8_t ** poutbuf,int * poutbuf_size,const uint8_t * buf,int buf_size)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 int out_size = 0;
61
62 ff_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
63 s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
64
65 for (i=0; i < buf_size; i++)
66 {
67 ff_dlog(avctx, "%02x ", buf[i]);
68 if (i % 16 == 15)
69 ff_dlog(avctx, "\n");
70 }
71
72 if (i % 16 != 0)
73 ff_dlog(avctx, "\n");
74
75 *poutbuf = buf;
76 *poutbuf_size = buf_size;
77
78 s->fetch_timestamp = 1;
79
80 if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
81 {
82 if (pc->packet_index != pc->packet_start)
83 {
84 ff_dlog(avctx, "Discarding %d bytes\n",
85 pc->packet_index - pc->packet_start);
86 }
87
88 pc->packet_start = 0;
89 pc->packet_index = 0;
90
91 if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
92 ff_dlog(avctx, "Bad packet header\n");
93 return buf_size;
94 }
95
96 buf_pos = 2;
97
98 pc->in_packet = 1;
99 } else {
100 if (pc->packet_start != 0)
101 {
102 if (pc->packet_index != pc->packet_start)
103 {
104 memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
105 pc->packet_index - pc->packet_start);
106
107 pc->packet_index -= pc->packet_start;
108 pc->packet_start = 0;
109 } else {
110 pc->packet_start = 0;
111 pc->packet_index = 0;
112 }
113 }
114 }
115
116 if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
117 return buf_size;
118
119 /* if not currently in a packet, pass data */
120 if (pc->in_packet == 0)
121 return buf_size;
122
123 memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
124 pc->packet_index += buf_size - buf_pos;
125
126 p = pc->packet_buf;
127 p_end = pc->packet_buf + pc->packet_index;
128
129 while (p < p_end)
130 {
131 if (*p == 0x0f)
132 {
133 if (6 <= p_end - p)
134 {
135 len = AV_RB16(p + 4);
136
137 if (len + 6 <= p_end - p)
138 {
139 out_size += len + 6;
140
141 p += len + 6;
142 } else
143 break;
144 } else
145 break;
146 } else if (*p == 0xff) {
147 if (1 < p_end - p)
148 {
149 ff_dlog(avctx, "Junk at end of packet\n");
150 }
151 pc->packet_index = p - pc->packet_buf;
152 pc->in_packet = 0;
153 break;
154 } else {
155 av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
156
157 pc->packet_index = p - pc->packet_buf;
158 pc->in_packet = 0;
159 break;
160 }
161 }
162
163 if (out_size > 0)
164 {
165 *poutbuf = pc->packet_buf;
166 *poutbuf_size = out_size;
167 pc->packet_start = *poutbuf_size;
168 }
169
170 if (s->pts == AV_NOPTS_VALUE)
171 s->pts = s->last_pts;
172
173 return buf_size;
174 }
175
dvbsub_parse_close(AVCodecParserContext * s)176 static av_cold void dvbsub_parse_close(AVCodecParserContext *s)
177 {
178 DVBSubParseContext *pc = s->priv_data;
179 av_freep(&pc->packet_buf);
180 }
181
182 AVCodecParser ff_dvbsub_parser = {
183 .codec_ids = { AV_CODEC_ID_DVB_SUBTITLE },
184 .priv_data_size = sizeof(DVBSubParseContext),
185 .parser_init = dvbsub_parse_init,
186 .parser_parse = dvbsub_parse,
187 .parser_close = dvbsub_parse_close,
188 };
189