if(firstBit) return -1;
int fps;  fps= get_bits(&s->gb, 5); s->bitrate= get_bits(&s->gb, 11); s->flipflop_rounding= get_bits1(&s->gb);
int msmpeg4_decode_ext_header(MpegEncContext * s, int buf_size){    int firstBit=0;        /* the alt_bitstream reader could read over the end so we need to check it */    if(get_bits_count(&s->gb) < buf_size*8) firstBit= get_bits1(&s->gb);        if(s->pict_type == P_TYPE)    {        if(firstBit) return -1; // havnt seen ext headers in P-Frames yet ;)    }    else    {        int unk;	if(!firstBit) // no header found	{	    s->flipflop_rounding= 0;	    s->bitrate= 0;	    return 0;	}		unk= get_bits(&s->gb, 4);	s->bitrate= get_bits(&s->gb, 11);	//	printf("%2d %4d ;; %1X\n", unk,s->bitrate, unk);    	s->flipflop_rounding= get_bits1(&s->gb);    }        return 0;}