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
32typedef struct {
33    ParseContext pc;
34    VC1Context v;
35} VC1ParseContext;
36
37static 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 */
87static 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
125static 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
152static 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
172AVCodecParser vc1_parser = {
173    { CODEC_ID_VC1 },
174    sizeof(VC1ParseContext),
175    NULL,
176    vc1_parse,
177    ff_parse1_close,
178    vc1_split,
179};
180