Merge commit 'b7f98659f21dce438c33b512e25fd64b8d07c347'
[ffmpeg.git] / libavcodec / dvbsub_parser.c
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 #include "internal.h"
29
30 /* Parser (mostly) copied from dvdsub.c */
31
32 #define PARSE_BUF_SIZE  (65536)
33
34
35 /* parser definition */
36 typedef struct DVBSubParseContext {
37     uint8_t *packet_buf;
38     int packet_start;
39     int packet_index;
40     int in_packet;
41 } DVBSubParseContext;
42
43 static av_cold int dvbsub_parse_init(AVCodecParserContext *s)
44 {
45     DVBSubParseContext *pc = s->priv_data;
46     pc->packet_buf = av_malloc(PARSE_BUF_SIZE);
47
48     return 0;
49 }
50
51 static int dvbsub_parse(AVCodecParserContext *s,
52                         AVCodecContext *avctx,
53                         const uint8_t **poutbuf, int *poutbuf_size,
54                         const uint8_t *buf, int buf_size)
55 {
56     DVBSubParseContext *pc = s->priv_data;
57     uint8_t *p, *p_end;
58     int i, len, buf_pos = 0;
59
60     ff_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
61             s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
62
63     for (i=0; i < buf_size; i++)
64     {
65         ff_dlog(avctx, "%02x ", buf[i]);
66         if (i % 16 == 15)
67             ff_dlog(avctx, "\n");
68     }
69
70     if (i % 16 != 0)
71         ff_dlog(avctx, "\n");
72
73     *poutbuf = NULL;
74     *poutbuf_size = 0;
75
76     s->fetch_timestamp = 1;
77
78     if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
79     {
80         if (pc->packet_index != pc->packet_start)
81         {
82             ff_dlog(avctx, "Discarding %d bytes\n",
83                     pc->packet_index - pc->packet_start);
84         }
85
86         pc->packet_start = 0;
87         pc->packet_index = 0;
88
89         if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
90             ff_dlog(avctx, "Bad packet header\n");
91             return -1;
92         }
93
94         buf_pos = 2;
95
96         pc->in_packet = 1;
97     } else {
98         if (pc->packet_start != 0)
99         {
100             if (pc->packet_index != pc->packet_start)
101             {
102                 memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
103                             pc->packet_index - pc->packet_start);
104
105                 pc->packet_index -= pc->packet_start;
106                 pc->packet_start = 0;
107             } else {
108                 pc->packet_start = 0;
109                 pc->packet_index = 0;
110             }
111         }
112     }
113
114     if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
115         return -1;
116
117 /* if not currently in a packet, discard data */
118     if (pc->in_packet == 0)
119         return buf_size;
120
121     memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
122     pc->packet_index += buf_size - buf_pos;
123
124     p = pc->packet_buf;
125     p_end = pc->packet_buf + pc->packet_index;
126
127     while (p < p_end)
128     {
129         if (*p == 0x0f)
130         {
131             if (6 <= p_end - p)
132             {
133                 len = AV_RB16(p + 4);
134
135                 if (len + 6 <= p_end - p)
136                 {
137                     *poutbuf_size += len + 6;
138
139                     p += len + 6;
140                 } else
141                     break;
142             } else
143                 break;
144         } else if (*p == 0xff) {
145             if (1 < p_end - p)
146             {
147                 ff_dlog(avctx, "Junk at end of packet\n");
148             }
149             pc->packet_index = p - pc->packet_buf;
150             pc->in_packet = 0;
151             break;
152         } else {
153             av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
154
155             pc->packet_index = p - pc->packet_buf;
156             pc->in_packet = 0;
157             break;
158         }
159     }
160
161     if (*poutbuf_size > 0)
162     {
163         *poutbuf = pc->packet_buf;
164         pc->packet_start = *poutbuf_size;
165     }
166
167     if (s->pts == AV_NOPTS_VALUE)
168         s->pts = s->last_pts;
169
170     return buf_size;
171 }
172
173 static av_cold void dvbsub_parse_close(AVCodecParserContext *s)
174 {
175     DVBSubParseContext *pc = s->priv_data;
176     av_freep(&pc->packet_buf);
177 }
178
179 AVCodecParser ff_dvbsub_parser = {
180     .codec_ids      = { AV_CODEC_ID_DVB_SUBTITLE },
181     .priv_data_size = sizeof(DVBSubParseContext),
182     .parser_init    = dvbsub_parse_init,
183     .parser_parse   = dvbsub_parse,
184     .parser_close   = dvbsub_parse_close,
185 };