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libavcodec/cavs_parser.c

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00001 /*
00002  * Chinese AVS video (AVS1-P2, JiZhun profile) parser.
00003  * Copyright (c) 2006  Stefan Gehrer <stefan.gehrer@gmx.de>
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00028 #include "parser.h"
00029 #include "cavs.h"
00030 
00031 
00036 static int cavs_find_frame_end(ParseContext *pc, const uint8_t *buf,
00037                                int buf_size) {
00038     int pic_found, i;
00039     uint32_t state;
00040 
00041     pic_found= pc->frame_start_found;
00042     state= pc->state;
00043 
00044     i=0;
00045     if(!pic_found){
00046         for(i=0; i<buf_size; i++){
00047             state= (state<<8) | buf[i];
00048             if(state == PIC_I_START_CODE || state == PIC_PB_START_CODE){
00049                 i++;
00050                 pic_found=1;
00051                 break;
00052             }
00053         }
00054     }
00055 
00056     if(pic_found){
00057         /* EOF considered as end of frame */
00058         if (buf_size == 0)
00059             return 0;
00060         for(; i<buf_size; i++){
00061             state= (state<<8) | buf[i];
00062             if((state&0xFFFFFF00) == 0x100){
00063                 if(state > SLICE_MAX_START_CODE){
00064                     pc->frame_start_found=0;
00065                     pc->state=-1;
00066                     return i-3;
00067                 }
00068             }
00069         }
00070     }
00071     pc->frame_start_found= pic_found;
00072     pc->state= state;
00073     return END_NOT_FOUND;
00074 }
00075 
00076 static int cavsvideo_parse(AVCodecParserContext *s,
00077                            AVCodecContext *avctx,
00078                            const uint8_t **poutbuf, int *poutbuf_size,
00079                            const uint8_t *buf, int buf_size)
00080 {
00081     ParseContext *pc = s->priv_data;
00082     int next;
00083 
00084     if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
00085         next= buf_size;
00086     }else{
00087         next= cavs_find_frame_end(pc, buf, buf_size);
00088 
00089         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
00090             *poutbuf = NULL;
00091             *poutbuf_size = 0;
00092             return buf_size;
00093         }
00094     }
00095     *poutbuf = buf;
00096     *poutbuf_size = buf_size;
00097     return next;
00098 }
00099 
00100 AVCodecParser cavsvideo_parser = {
00101     { CODEC_ID_CAVS },
00102     sizeof(ParseContext1),
00103     NULL,
00104     cavsvideo_parse,
00105     ff_parse1_close,
00106     ff_mpeg4video_split,
00107 };

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