int ff_intel_h263_decode_picture_header(MpegEncContext *s)

{

    int format;



    

    if (get_bits_long(&s->gb, 22) != 0x20) {

        av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");

        return -1;

    }

    s->picture_number = get_bits(&s->gb, 8); 



    if (get_bits1(&s->gb) != 1) {

        av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");

        return -1;      

    }

    if (get_bits1(&s->gb) != 0) {

        av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");

        return -1;      

    }

    skip_bits1(&s->gb);         

    skip_bits1(&s->gb);         

    skip_bits1(&s->gb);         



    format = get_bits(&s->gb, 3);

    if (format == 0 || format == 6) {

        av_log(s->avctx, AV_LOG_ERROR, "Intel H263 free format not supported\n");

        return -1;

    }

    s->h263_plus = 0;



    s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);



    s->unrestricted_mv = get_bits1(&s->gb);

    s->h263_long_vectors = s->unrestricted_mv;



    if (get_bits1(&s->gb) != 0) {

        av_log(s->avctx, AV_LOG_ERROR, "SAC not supported\n");

        return -1;      

    }

    s->obmc= get_bits1(&s->gb);

    s->pb_frame = get_bits1(&s->gb);



    if (format < 6) {

        s->width = ff_h263_format[format][0];

        s->height = ff_h263_format[format][1];

        s->avctx->sample_aspect_ratio.num = 12;

        s->avctx->sample_aspect_ratio.den = 11;

    } else {

        format = get_bits(&s->gb, 3);

        if(format == 0 || format == 7){

            av_log(s->avctx, AV_LOG_ERROR, "Wrong Intel H263 format\n");

            return -1;

        }

        if(get_bits(&s->gb, 2))

            av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");

        s->loop_filter = get_bits1(&s->gb);

        if(get_bits1(&s->gb))

            av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");

        if(get_bits1(&s->gb))

            s->pb_frame = 2;

        if(get_bits(&s->gb, 5))

            av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");

        if(get_bits(&s->gb, 5) != 1)

            av_log(s->avctx, AV_LOG_ERROR, "Invalid marker\n");

    }

    if(format == 6){

        int ar = get_bits(&s->gb, 4);

        skip_bits(&s->gb, 9); 

        skip_bits1(&s->gb);

        skip_bits(&s->gb, 9); 

        if(ar == 15){

            s->avctx->sample_aspect_ratio.num = get_bits(&s->gb, 8); 

            s->avctx->sample_aspect_ratio.den = get_bits(&s->gb, 8); 

        } else {

            s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[ar];

        }

        if (s->avctx->sample_aspect_ratio.num == 0)

            av_log(s->avctx, AV_LOG_ERROR, "Invalid aspect ratio.\n");

    }



    s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);

    skip_bits1(&s->gb); 



    if(s->pb_frame){

        skip_bits(&s->gb, 3); 

        skip_bits(&s->gb, 2); 

    }



    

    while (get_bits1(&s->gb) != 0) {

        skip_bits(&s->gb, 8);

    }

    s->f_code = 1;



    s->y_dc_scale_table=

    s->c_dc_scale_table= ff_mpeg1_dc_scale_table;



    ff_h263_show_pict_info(s);



    return 0;

}
