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 "dsputil.h"
23#include "bitstream.h"
24
25//#define DEBUG
26//#define DEBUG_PACKET_CONTENTS
27
28/* Parser (mostly) copied from dvdsub.c */
29
30#define PARSE_BUF_SIZE  (65536)
31
32
33/* parser definition */
34typedef struct DVBSubParseContext {
35    uint8_t *packet_buf;
36    int packet_start;
37    int packet_index;
38    int in_packet;
39} DVBSubParseContext;
40
41static av_cold int dvbsub_parse_init(AVCodecParserContext *s)
42{
43    DVBSubParseContext *pc = s->priv_data;
44    pc->packet_buf = av_malloc(PARSE_BUF_SIZE);
45
46    return 0;
47}
48
49static int dvbsub_parse(AVCodecParserContext *s,
50                        AVCodecContext *avctx,
51                        const uint8_t **poutbuf, int *poutbuf_size,
52                        const uint8_t *buf, int buf_size)
53{
54    DVBSubParseContext *pc = s->priv_data;
55    uint8_t *p, *p_end;
56    int len, buf_pos = 0;
57
58#ifdef DEBUG
59    av_log(avctx, AV_LOG_INFO, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
60            s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
61#endif
62
63#ifdef DEBUG_PACKET_CONTENTS
64    int i;
65
66    for (i=0; i < buf_size; i++)
67    {
68        av_log(avctx, AV_LOG_INFO, "%02x ", buf[i]);
69        if (i % 16 == 15)
70            av_log(avctx, AV_LOG_INFO, "\n");
71    }
72
73    if (i % 16 != 0)
74        av_log(avctx, AV_LOG_INFO, "\n");
75
76#endif
77
78    *poutbuf = NULL;
79    *poutbuf_size = 0;
80
81    s->fetch_timestamp = 1;
82
83    if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
84    {
85        if (pc->packet_index != pc->packet_start)
86        {
87#ifdef DEBUG
88            av_log(avctx, AV_LOG_INFO, "Discarding %d bytes\n",
89                pc->packet_index - pc->packet_start);
90#endif
91        }
92
93        pc->packet_start = 0;
94        pc->packet_index = 0;
95
96        if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
97#ifdef DEBUG
98            av_log(avctx, AV_LOG_INFO, "Bad packet header\n");
99#endif
100            return -1;
101        }
102
103        buf_pos = 2;
104
105        pc->in_packet = 1;
106    } else {
107        if (pc->packet_start != 0)
108        {
109            if (pc->packet_index != pc->packet_start)
110            {
111                memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
112                            pc->packet_index - pc->packet_start);
113
114                pc->packet_index -= pc->packet_start;
115                pc->packet_start = 0;
116            } else {
117                pc->packet_start = 0;
118                pc->packet_index = 0;
119            }
120        }
121    }
122
123    if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
124        return -1;
125
126/* if not currently in a packet, discard data */
127    if (pc->in_packet == 0)
128        return buf_size;
129
130    memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
131    pc->packet_index += buf_size - buf_pos;
132
133    p = pc->packet_buf;
134    p_end = pc->packet_buf + pc->packet_index;
135
136    while (p < p_end)
137    {
138        if (*p == 0x0f)
139        {
140            if (p + 6 <= p_end)
141            {
142                len = AV_RB16(p + 4);
143
144                if (p + len + 6 <= p_end)
145                {
146                    *poutbuf_size += len + 6;
147
148                    p += len + 6;
149                } else
150                    break;
151            } else
152                break;
153        } else if (*p == 0xff) {
154            if (p + 1 < p_end)
155            {
156#ifdef DEBUG
157                av_log(avctx, AV_LOG_INFO, "Junk at end of packet\n");
158#endif
159            }
160            pc->packet_index = p - pc->packet_buf;
161            pc->in_packet = 0;
162            break;
163        } else {
164            av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
165
166            pc->packet_index = p - pc->packet_buf;
167            pc->in_packet = 0;
168            break;
169        }
170    }
171
172    if (*poutbuf_size > 0)
173    {
174        *poutbuf = pc->packet_buf;
175        pc->packet_start = *poutbuf_size;
176    }
177
178    if (s->pts == AV_NOPTS_VALUE)
179        s->pts = s->last_pts;
180
181    return buf_size;
182}
183
184static av_cold void dvbsub_parse_close(AVCodecParserContext *s)
185{
186    DVBSubParseContext *pc = s->priv_data;
187    av_freep(&pc->packet_buf);
188}
189
190AVCodecParser dvbsub_parser = {
191    { CODEC_ID_DVB_SUBTITLE },
192    sizeof(DVBSubParseContext),
193    dvbsub_parse_init,
194    dvbsub_parse,
195    dvbsub_parse_close,
196};
197