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 * Find the end of the current frame in the bitstream.
34 * @return the position of the first byte of the next frame, or -1
35 */
cavs_find_frame_end(ParseContext * pc,const uint8_t * buf,int buf_size)36 static 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
cavsvideo_parse(AVCodecParserContext * s,AVCodecContext * avctx,const uint8_t ** poutbuf,int * poutbuf_size,const uint8_t * buf,int buf_size)76 static 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
100 AVCodecParser ff_cavsvideo_parser = {
101 .codec_ids = { AV_CODEC_ID_CAVS },
102 .priv_data_size = sizeof(ParseContext),
103 .parser_parse = cavsvideo_parse,
104 .parser_close = ff_parse_close,
105 .split = ff_mpeg4video_split,
106 };
107