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1 | /* |
2 | * DNxHD/VC-3 parser | |
3 | * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr> | |
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 | * DNxHD/VC-3 parser | |
25 | */ | |
26 | ||
27 | #include "parser.h" | |
28 | ||
29 | #define DNXHD_HEADER_PREFIX 0x000002800100 | |
30 | ||
31 | typedef struct { | |
32 | ParseContext pc; | |
33 | int interlaced; | |
34 | int cur_field; /* first field is 0, second is 1 */ | |
35 | } DNXHDParserContext; | |
36 | ||
37 | static int dnxhd_find_frame_end(DNXHDParserContext *dctx, | |
38 | const uint8_t *buf, int buf_size) | |
39 | { | |
40 | ParseContext *pc = &dctx->pc; | |
41 | uint64_t state = pc->state64; | |
42 | int pic_found = pc->frame_start_found; | |
43 | int i = 0; | |
44 | int interlaced = dctx->interlaced; | |
45 | int cur_field = dctx->cur_field; | |
46 | ||
47 | if (!pic_found) { | |
48 | for (i = 0; i < buf_size; i++) { | |
49 | state = (state << 8) | buf[i]; | |
50 | if ((state & 0xffffffffff00LL) == DNXHD_HEADER_PREFIX) { | |
51 | i++; | |
52 | pic_found = 1; | |
53 | interlaced = (state&2)>>1; /* byte following the 5-byte header prefix */ | |
54 | cur_field = state&1; | |
55 | break; | |
56 | } | |
57 | } | |
58 | } | |
59 | ||
60 | if (pic_found) { | |
61 | if (!buf_size) /* EOF considered as end of frame */ | |
62 | return 0; | |
63 | for (; i < buf_size; i++) { | |
64 | state = (state << 8) | buf[i]; | |
65 | if ((state & 0xffffffffff00LL) == DNXHD_HEADER_PREFIX) { | |
66 | if (!interlaced || dctx->cur_field) { | |
67 | pc->frame_start_found = 0; | |
68 | pc->state64 = -1; | |
69 | dctx->interlaced = interlaced; | |
70 | dctx->cur_field = 0; | |
71 | return i - 5; | |
72 | } else { | |
73 | /* continue, to get the second field */ | |
74 | dctx->interlaced = interlaced = (state&2)>>1; | |
75 | dctx->cur_field = cur_field = state&1; | |
76 | } | |
77 | } | |
78 | } | |
79 | } | |
80 | pc->frame_start_found = pic_found; | |
81 | pc->state64 = state; | |
82 | dctx->interlaced = interlaced; | |
83 | dctx->cur_field = cur_field; | |
84 | return END_NOT_FOUND; | |
85 | } | |
86 | ||
87 | static int dnxhd_parse(AVCodecParserContext *s, | |
88 | AVCodecContext *avctx, | |
89 | const uint8_t **poutbuf, int *poutbuf_size, | |
90 | const uint8_t *buf, int buf_size) | |
91 | { | |
92 | DNXHDParserContext *dctx = s->priv_data; | |
93 | ParseContext *pc = &dctx->pc; | |
94 | int next; | |
95 | ||
96 | if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { | |
97 | next = buf_size; | |
98 | } else { | |
99 | next = dnxhd_find_frame_end(dctx, buf, buf_size); | |
100 | if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { | |
101 | *poutbuf = NULL; | |
102 | *poutbuf_size = 0; | |
103 | return buf_size; | |
104 | } | |
105 | } | |
106 | *poutbuf = buf; | |
107 | *poutbuf_size = buf_size; | |
108 | return next; | |
109 | } | |
110 | ||
111 | AVCodecParser ff_dnxhd_parser = { | |
112 | .codec_ids = { AV_CODEC_ID_DNXHD }, | |
113 | .priv_data_size = sizeof(DNXHDParserContext), | |
114 | .parser_parse = dnxhd_parse, | |
115 | .parser_close = ff_parse_close, | |
116 | }; |