cavs_parser.c 3.04 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
/*
 * Chinese AVS video (AVS1-P2, JiZhun profile) parser.
 * Copyright (c) 2006  Stefan Gehrer <stefan.gehrer@gmx.de>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * 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 25 26 27 28 29 30 31 32
 * Chinese AVS video (AVS1-P2, JiZhun profile) parser
 * @author Stefan Gehrer <stefan.gehrer@gmx.de>
 */

#include "parser.h"
#include "cavs.h"


/**
33
 * Find the end of the current frame in the bitstream.
34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62
 * @return the position of the first byte of the next frame, or -1
 */
static int cavs_find_frame_end(ParseContext *pc, const uint8_t *buf,
                               int buf_size) {
    int pic_found, i;
    uint32_t state;

    pic_found= pc->frame_start_found;
    state= pc->state;

    i=0;
    if(!pic_found){
        for(i=0; i<buf_size; i++){
            state= (state<<8) | buf[i];
            if(state == PIC_I_START_CODE || state == PIC_PB_START_CODE){
                i++;
                pic_found=1;
                break;
            }
        }
    }

    if(pic_found){
        /* EOF considered as end of frame */
        if (buf_size == 0)
            return 0;
        for(; i<buf_size; i++){
            state= (state<<8) | buf[i];
            if((state&0xFFFFFF00) == 0x100){
63
                if(state > SLICE_MAX_START_CODE){
64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
                    pc->frame_start_found=0;
                    pc->state=-1;
                    return i-3;
                }
            }
        }
    }
    pc->frame_start_found= pic_found;
    pc->state= state;
    return END_NOT_FOUND;
}

static int cavsvideo_parse(AVCodecParserContext *s,
                           AVCodecContext *avctx,
                           const uint8_t **poutbuf, int *poutbuf_size,
                           const uint8_t *buf, int buf_size)
{
    ParseContext *pc = s->priv_data;
    int next;

    if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
        next= buf_size;
    }else{
        next= cavs_find_frame_end(pc, buf, buf_size);

        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
            *poutbuf = NULL;
            *poutbuf_size = 0;
            return buf_size;
        }
    }
    *poutbuf = buf;
    *poutbuf_size = buf_size;
    return next;
}

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
};