1/*
2 * Chinese AVS video (AVS1-P2, JiZhun profile) parser.
3 * Copyright (c) 2006  Stefan Gehrer <stefan.gehrer@gmx.de>
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 * Chinese AVS video (AVS1-P2, JiZhun profile) parser
25 * @author Stefan Gehrer <stefan.gehrer@gmx.de>
26 */
27
28#include "parser.h"
29#include "cavs.h"
30
31
32/**
33 * finds the end of the current frame in the bitstream.
34 * @return the position of the first byte of the next frame, or -1
35 */
36static int cavs_find_frame_end(ParseContext *pc, const uint8_t *buf,
37                               int buf_size) {
38    int pic_found, i;
39    uint32_t state;
40
41    pic_found= pc->frame_start_found;
42    state= pc->state;
43
44    i=0;
45    if(!pic_found){
46        for(i=0; i<buf_size; i++){
47            state= (state<<8) | buf[i];
48            if(state == PIC_I_START_CODE || state == PIC_PB_START_CODE){
49                i++;
50                pic_found=1;
51                break;
52            }
53        }
54    }
55
56    if(pic_found){
57        /* EOF considered as end of frame */
58        if (buf_size == 0)
59            return 0;
60        for(; i<buf_size; i++){
61            state= (state<<8) | buf[i];
62            if((state&0xFFFFFF00) == 0x100){
63                if(state > SLICE_MAX_START_CODE){
64                    pc->frame_start_found=0;
65                    pc->state=-1;
66                    return i-3;
67                }
68            }
69        }
70    }
71    pc->frame_start_found= pic_found;
72    pc->state= state;
73    return END_NOT_FOUND;
74}
75
76static int cavsvideo_parse(AVCodecParserContext *s,
77                           AVCodecContext *avctx,
78                           const uint8_t **poutbuf, int *poutbuf_size,
79                           const uint8_t *buf, int buf_size)
80{
81    ParseContext *pc = s->priv_data;
82    int next;
83
84    if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
85        next= buf_size;
86    }else{
87        next= cavs_find_frame_end(pc, buf, buf_size);
88
89        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
90            *poutbuf = NULL;
91            *poutbuf_size = 0;
92            return buf_size;
93        }
94    }
95    *poutbuf = buf;
96    *poutbuf_size = buf_size;
97    return next;
98}
99
100AVCodecParser cavsvideo_parser = {
101    { CODEC_ID_CAVS },
102    sizeof(ParseContext1),
103    NULL,
104    cavsvideo_parse,
105    ff_parse1_close,
106    ff_mpeg4video_split,
107};
108