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 Libav.
7 *
8 * Libav 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 * Libav 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 Libav; 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    s->repeat_pict = 0;
49
50    for(start = buf, end = buf + buf_size; next < end; start = next){
51        int buf2_size, size;
52
53        next = find_next_marker(start + 4, end);
54        size = next - start - 4;
55        buf2_size = vc1_unescape_buffer(start + 4, size, buf2);
56        init_get_bits(&gb, buf2, buf2_size * 8);
57        if(size <= 0) continue;
58        switch(AV_RB32(start)){
59        case VC1_CODE_SEQHDR:
60            vc1_decode_sequence_header(avctx, &vpc->v, &gb);
61            break;
62        case VC1_CODE_ENTRYPOINT:
63            vc1_decode_entry_point(avctx, &vpc->v, &gb);
64            break;
65        case VC1_CODE_FRAME:
66            if(vpc->v.profile < PROFILE_ADVANCED)
67                vc1_parse_frame_header    (&vpc->v, &gb);
68            else
69                vc1_parse_frame_header_adv(&vpc->v, &gb);
70
71            /* keep AV_PICTURE_TYPE_BI internal to VC1 */
72            if (vpc->v.s.pict_type == AV_PICTURE_TYPE_BI)
73                s->pict_type = AV_PICTURE_TYPE_B;
74            else
75                s->pict_type = vpc->v.s.pict_type;
76
77            if (avctx->ticks_per_frame > 1){
78                // process pulldown flags
79                s->repeat_pict = 1;
80                // Pulldown flags are only valid when 'broadcast' has been set.
81                // So ticks_per_frame will be 2
82                if (vpc->v.rff){
83                    // repeat field
84                    s->repeat_pict = 2;
85                }else if (vpc->v.rptfrm){
86                    // repeat frames
87                    s->repeat_pict = vpc->v.rptfrm * 2 + 1;
88                }
89            }
90
91            break;
92        }
93    }
94
95    av_free(buf2);
96}
97
98/**
99 * Find the end of the current frame in the bitstream.
100 * @return the position of the first byte of the next frame, or -1
101 */
102static int vc1_find_frame_end(ParseContext *pc, const uint8_t *buf,
103                               int buf_size) {
104    int pic_found, i;
105    uint32_t state;
106
107    pic_found= pc->frame_start_found;
108    state= pc->state;
109
110    i=0;
111    if(!pic_found){
112        for(i=0; i<buf_size; i++){
113            state= (state<<8) | buf[i];
114            if(state == VC1_CODE_FRAME || state == VC1_CODE_FIELD){
115                i++;
116                pic_found=1;
117                break;
118            }
119        }
120    }
121
122    if(pic_found){
123        /* EOF considered as end of frame */
124        if (buf_size == 0)
125            return 0;
126        for(; i<buf_size; i++){
127            state= (state<<8) | buf[i];
128            if(IS_MARKER(state) && state != VC1_CODE_FIELD && state != VC1_CODE_SLICE){
129                pc->frame_start_found=0;
130                pc->state=-1;
131                return i-3;
132            }
133        }
134    }
135    pc->frame_start_found= pic_found;
136    pc->state= state;
137    return END_NOT_FOUND;
138}
139
140static int vc1_parse(AVCodecParserContext *s,
141                           AVCodecContext *avctx,
142                           const uint8_t **poutbuf, int *poutbuf_size,
143                           const uint8_t *buf, int buf_size)
144{
145    VC1ParseContext *vpc = s->priv_data;
146    int next;
147
148    if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
149        next= buf_size;
150    }else{
151        next= vc1_find_frame_end(&vpc->pc, buf, buf_size);
152
153        if (ff_combine_frame(&vpc->pc, next, &buf, &buf_size) < 0) {
154            *poutbuf = NULL;
155            *poutbuf_size = 0;
156            return buf_size;
157        }
158    }
159
160    vc1_extract_headers(s, avctx, buf, buf_size);
161
162    *poutbuf = buf;
163    *poutbuf_size = buf_size;
164    return next;
165}
166
167static int vc1_split(AVCodecContext *avctx,
168                           const uint8_t *buf, int buf_size)
169{
170    int i;
171    uint32_t state= -1;
172    int charged=0;
173
174    for(i=0; i<buf_size; i++){
175        state= (state<<8) | buf[i];
176        if(IS_MARKER(state)){
177            if(state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT){
178                charged=1;
179            }else if(charged){
180                return i-3;
181            }
182        }
183    }
184    return 0;
185}
186
187static int vc1_parse_init(AVCodecParserContext *s)
188{
189    VC1ParseContext *vpc = s->priv_data;
190    vpc->v.s.slice_context_count = 1;
191    return ff_vc1_init_common(&vpc->v);
192}
193
194AVCodecParser ff_vc1_parser = {
195    .codec_ids      = { CODEC_ID_VC1 },
196    .priv_data_size = sizeof(VC1ParseContext),
197    .parser_init    = vc1_parse_init,
198    .parser_parse   = vc1_parse,
199    .parser_close   = ff_parse1_close,
200    .split          = vc1_split,
201};
202