6e559dec9b2777b00a6962a5ee10fbafab5531e6
[libav.git] / libavcodec / vc1_parser.c
1 /*
2 * VC-1 and WMV3 parser
3 * Copyright (c) 2006-2007 Konstantin Shishkov
4 * Partly based on vc9.c (c) 2005 Anonymous, Alex Beregszaszi, Michael Niedermayer
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /**
24 * @file
25 * VC-1 and WMV3 parser
26 */
27
28 #include "parser.h"
29 #include "vc1.h"
30 #include "get_bits.h"
31
32 typedef struct {
33 ParseContext pc;
34 VC1Context v;
35 } VC1ParseContext;
36
37 static void vc1_extract_headers(AVCodecParserContext *s, AVCodecContext *avctx,
38 const uint8_t *buf, int buf_size)
39 {
40 VC1ParseContext *vpc = s->priv_data;
41 GetBitContext gb;
42 const uint8_t *start, *end, *next;
43 uint8_t *buf2 = av_mallocz(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
44
45 vpc->v.s.avctx = avctx;
46 vpc->v.parse_only = 1;
47 next = buf;
48
49 for(start = buf, end = buf + buf_size; next < end; start = next){
50 int buf2_size, size;
51
52 next = find_next_marker(start + 4, end);
53 size = next - start - 4;
54 buf2_size = vc1_unescape_buffer(start + 4, size, buf2);
55 init_get_bits(&gb, buf2, buf2_size * 8);
56 if(size <= 0) continue;
57 switch(AV_RB32(start)){
58 case VC1_CODE_SEQHDR:
59 vc1_decode_sequence_header(avctx, &vpc->v, &gb);
60 break;
61 case VC1_CODE_ENTRYPOINT:
62 vc1_decode_entry_point(avctx, &vpc->v, &gb);
63 break;
64 case VC1_CODE_FRAME:
65 if(vpc->v.profile < PROFILE_ADVANCED)
66 vc1_parse_frame_header (&vpc->v, &gb);
67 else
68 vc1_parse_frame_header_adv(&vpc->v, &gb);
69
70 /* keep FF_BI_TYPE internal to VC1 */
71 if (vpc->v.s.pict_type == FF_BI_TYPE)
72 s->pict_type = FF_B_TYPE;
73 else
74 s->pict_type = vpc->v.s.pict_type;
75
76 break;
77 }
78 }
79
80 av_free(buf2);
81 }
82
83 /**
84 * finds the end of the current frame in the bitstream.
85 * @return the position of the first byte of the next frame, or -1
86 */
87 static int vc1_find_frame_end(ParseContext *pc, const uint8_t *buf,
88 int buf_size) {
89 int pic_found, i;
90 uint32_t state;
91
92 pic_found= pc->frame_start_found;
93 state= pc->state;
94
95 i=0;
96 if(!pic_found){
97 for(i=0; i<buf_size; i++){
98 state= (state<<8) | buf[i];
99 if(state == VC1_CODE_FRAME || state == VC1_CODE_FIELD){
100 i++;
101 pic_found=1;
102 break;
103 }
104 }
105 }
106
107 if(pic_found){
108 /* EOF considered as end of frame */
109 if (buf_size == 0)
110 return 0;
111 for(; i<buf_size; i++){
112 state= (state<<8) | buf[i];
113 if(IS_MARKER(state) && state != VC1_CODE_FIELD && state != VC1_CODE_SLICE){
114 pc->frame_start_found=0;
115 pc->state=-1;
116 return i-3;
117 }
118 }
119 }
120 pc->frame_start_found= pic_found;
121 pc->state= state;
122 return END_NOT_FOUND;
123 }
124
125 static int vc1_parse(AVCodecParserContext *s,
126 AVCodecContext *avctx,
127 const uint8_t **poutbuf, int *poutbuf_size,
128 const uint8_t *buf, int buf_size)
129 {
130 VC1ParseContext *vpc = s->priv_data;
131 int next;
132
133 if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
134 next= buf_size;
135 }else{
136 next= vc1_find_frame_end(&vpc->pc, buf, buf_size);
137
138 if (ff_combine_frame(&vpc->pc, next, &buf, &buf_size) < 0) {
139 *poutbuf = NULL;
140 *poutbuf_size = 0;
141 return buf_size;
142 }
143 }
144
145 vc1_extract_headers(s, avctx, buf, buf_size);
146
147 *poutbuf = buf;
148 *poutbuf_size = buf_size;
149 return next;
150 }
151
152 static int vc1_split(AVCodecContext *avctx,
153 const uint8_t *buf, int buf_size)
154 {
155 int i;
156 uint32_t state= -1;
157 int charged=0;
158
159 for(i=0; i<buf_size; i++){
160 state= (state<<8) | buf[i];
161 if(IS_MARKER(state)){
162 if(state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT){
163 charged=1;
164 }else if(charged){
165 return i-3;
166 }
167 }
168 }
169 return 0;
170 }
171
172 AVCodecParser vc1_parser = {
173 { CODEC_ID_VC1 },
174 sizeof(VC1ParseContext),
175 NULL,
176 vc1_parse,
177 ff_parse1_close,
178 vc1_split,
179 };