1 /*
2 * DPX parser
3 * Copyright (c) 2013 Paul B Mahol
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 /**
23 * @file
24 * DPX parser
25 */
26
27 #include "libavutil/bswap.h"
28 #include "libavutil/common.h"
29
30 #include "parser.h"
31
32 typedef struct DPXParseContext {
33 ParseContext pc;
34 uint32_t index;
35 uint32_t fsize;
36 uint32_t remaining_size;
37 int is_be;
38 } DPXParseContext;
39
dpx_parse(AVCodecParserContext * s,AVCodecContext * avctx,const uint8_t ** poutbuf,int * poutbuf_size,const uint8_t * buf,int buf_size)40 static int dpx_parse(AVCodecParserContext *s, AVCodecContext *avctx,
41 const uint8_t **poutbuf, int *poutbuf_size,
42 const uint8_t *buf, int buf_size)
43 {
44 DPXParseContext *d = s->priv_data;
45 uint32_t state = d->pc.state;
46 int next = END_NOT_FOUND;
47 int i = 0;
48
49 s->pict_type = AV_PICTURE_TYPE_I;
50
51 *poutbuf_size = 0;
52 if (buf_size == 0)
53 next = 0;
54
55 if (!d->pc.frame_start_found) {
56 for (; i < buf_size; i++) {
57 state = (state << 8) | buf[i];
58 if (state == MKBETAG('S','D','P','X') ||
59 state == MKTAG('S','D','P','X')) {
60 d->pc.frame_start_found = 1;
61 d->is_be = state == MKBETAG('S','D','P','X');
62 d->index = 0;
63 break;
64 }
65 }
66 d->pc.state = state;
67 } else {
68 if (d->remaining_size) {
69 i = FFMIN(d->remaining_size, buf_size);
70 d->remaining_size -= i;
71 if (d->remaining_size)
72 goto flush;
73 }
74 }
75
76 for (; d->pc.frame_start_found && i < buf_size; i++) {
77 d->pc.state = (d->pc.state << 8) | buf[i];
78 d->index++;
79 if (d->index == 17) {
80 d->fsize = d->is_be ? d->pc.state : av_bswap32(d->pc.state);
81 if (d->fsize <= 1664) {
82 d->pc.frame_start_found = 0;
83 goto flush;
84 }
85 if (d->fsize > buf_size - i + 19)
86 d->remaining_size = d->fsize - buf_size + i - 19;
87 else
88 i += d->fsize - 19;
89
90 break;
91 } else if (d->index > 17) {
92 if (d->pc.state == MKBETAG('S','D','P','X') ||
93 d->pc.state == MKTAG('S','D','P','X')) {
94 next = i - 3;
95 break;
96 }
97 }
98 }
99
100 flush:
101 if (ff_combine_frame(&d->pc, next, &buf, &buf_size) < 0)
102 return buf_size;
103
104 d->pc.frame_start_found = 0;
105
106 *poutbuf = buf;
107 *poutbuf_size = buf_size;
108 return next;
109 }
110
111 AVCodecParser ff_dpx_parser = {
112 .codec_ids = { AV_CODEC_ID_DPX },
113 .priv_data_size = sizeof(DPXParseContext),
114 .parser_parse = dpx_parse,
115 .parser_close = ff_parse_close,
116 };
117