PeerStreamer

/*

 * H.263 parser

 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>

 *

 * 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

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * H.263 parser

 */

#include "parser.h"

#include "h263_parser.h"

int ff_h263_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){

    int vop_found, i;

    uint32_t state;

    vop_found= pc->frame_start_found;

    state= pc->state;

    i=0;

    if(!vop_found){

        for(i=0; i<buf_size; i++){

            state= (state<<8) | buf[i];

            if(state>>(32-22) == 0x20){

                i++;

                vop_found=1;

                break;

            }

        }

    }

    if(vop_found){

      for(; i<buf_size; i++){

        state= (state<<8) | buf[i];

        if(state>>(32-22) == 0x20){

            pc->frame_start_found=0;

            pc->state=-1;

            return i-3;

        }

      }

    }

    pc->frame_start_found= vop_found;

    pc->state= state;

    return END_NOT_FOUND;

}

static int h263_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;

    next= ff_h263_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;

}

AVCodecParser ff_h263_parser = {

    { CODEC_ID_H263 },

    sizeof(ParseContext),

    NULL,

    h263_parse,

    ff_parse_close,

};