[libav.git] / libavformat / h263dec.c

/*
 * RAW H.263 video demuxer
 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "avformat.h"
#include "rawdec.h"

static int h263_probe(AVProbeData *p)
{
    uint64_t code= -1;
    int i;
    int valid_psc=0;
    int invalid_psc=0;
    int res_change=0;
    int src_fmt, last_src_fmt=-1;
    int last_gn=0;

    for(i=0; i<p->buf_size; i++){
        code = (code<<8) + p->buf[i];
        if ((code & 0xfffffc0000) == 0x800000) {
            src_fmt= (code>>2)&3;
            if(   src_fmt != last_src_fmt
               && last_src_fmt>0 && last_src_fmt<6
               && src_fmt<6)
                res_change++;

            if((code&0x300)==0x200 && src_fmt){
                valid_psc++;
                last_gn=0;
            }else
                invalid_psc++;
            last_src_fmt= src_fmt;
        } else if((code & 0xffff800000) == 0x800000) {
            int gn= (code>>(23-5)) & 0x1F;
            if(gn<last_gn){
                invalid_psc++;
            }else
                last_gn= gn;
        }
    }
    if(valid_psc > 2*invalid_psc + 2*res_change + 3){
        return AVPROBE_SCORE_EXTENSION;
    }else if(valid_psc > 2*invalid_psc)
        return AVPROBE_SCORE_EXTENSION / 2;
    return 0;
}

FF_DEF_RAWVIDEO_DEMUXER(h263, "raw H.263", h263_probe, NULL, AV_CODEC_ID_H263)
Commit	Line	Data
	1	/*
	2	* RAW H.263 video demuxer
	3	* Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
	4	*
	5	* This file is part of Libav.
	6	*
	7	* Libav 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	* Libav 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 Libav; if not, write to the Free Software
	19	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	20	*/
	21
	22	#include "avformat.h"
	23	#include "rawdec.h"
	24
	25	static int h263_probe(AVProbeData *p)
	26	{
	27	uint64_t code= -1;
	28	int i;
	29	int valid_psc=0;
	30	int invalid_psc=0;
	31	int res_change=0;
	32	int src_fmt, last_src_fmt=-1;
	33	int last_gn=0;
	34
	35	for(i=0; i<p->buf_size; i++){
	36	code = (code<<8) + p->buf[i];
	37	if ((code & 0xfffffc0000) == 0x800000) {
	38	src_fmt= (code>>2)&3;
	39	if( src_fmt != last_src_fmt
	40	&& last_src_fmt>0 && last_src_fmt<6
	41	&& src_fmt<6)
	42	res_change++;
	43
	44	if((code&0x300)==0x200 && src_fmt){
	45	valid_psc++;
	46	last_gn=0;
	47	}else
	48	invalid_psc++;
	49	last_src_fmt= src_fmt;
	50	} else if((code & 0xffff800000) == 0x800000) {
	51	int gn= (code>>(23-5)) & 0x1F;
	52	if(gn<last_gn){
	53	invalid_psc++;
	54	}else
	55	last_gn= gn;
	56	}
	57	}
	58	if(valid_psc > 2invalid_psc + 2res_change + 3){
	59	return AVPROBE_SCORE_EXTENSION;
	60	}else if(valid_psc > 2*invalid_psc)
	61	return AVPROBE_SCORE_EXTENSION / 2;
	62	return 0;
	63	}
	64
	65	FF_DEF_RAWVIDEO_DEMUXER(h263, "raw H.263", h263_probe, NULL, AV_CODEC_ID_H263)