skip_bits(&a->gb, 8*8);
static int decode_frame(AVCodecContext *avctx,                         void *data, int *data_size,                        uint8_t *buf, int buf_size){    MDECContext * const a = avctx->priv_data;    AVFrame *picture = data;    AVFrame * const p= (AVFrame*)&a->picture;    int i;    *data_size = 0;    /* special case for last picture */    if (buf_size == 0) {        return 0;    }    if(p->data[0])        avctx->release_buffer(avctx, p);    p->reference= 0;    if(avctx->get_buffer(avctx, p) < 0){        fprintf(stderr, "get_buffer() failed\n");        return -1;    }    p->pict_type= I_TYPE;    p->key_frame= 1;    a->last_dc[0]=    a->last_dc[1]=    a->last_dc[2]= 0;    a->bitstream_buffer= av_fast_realloc(a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);    for(i=0; i<buf_size; i+=2){        a->bitstream_buffer[i]  = buf[i+1];        a->bitstream_buffer[i+1]= buf[i  ];    }//    a->dsp.bswap_buf((uint32_t*)a->bitstream_buffer, (uint32_t*)buf, buf_size/4);    init_get_bits(&a->gb, a->bitstream_buffer, buf_size*8);        /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */    skip_bits(&a->gb, 32);    a->qscale=  get_bits(&a->gb, 16);    a->version= get_bits(&a->gb, 16);    skip_bits(&a->gb, 8*8);         printf("qscale:%d (0x%X), version:%d (0x%X)\n", a->qscale, a->qscale, a->version, a->version);        for(a->mb_y=0; a->mb_y<a->mb_height; a->mb_y++){        for(a->mb_x=0; a->mb_x<a->mb_width; a->mb_x++){            if( decode_mb(a, a->block) <0)                return -1;                         idct_put(a, a->mb_x, a->mb_y);        }    }#if 0    int i;printf("%d %d\n", 8*buf_size, get_bits_count(&a->gb));for(i=get_bits_count(&a->gb); i<8*buf_size; i++){    printf("%d", get_bits1(&a->gb));}for(i=0; i<s->avctx->extradata_size; i++){    printf("%c\n", ((uint8_t*)s->avctx->extradata)[i]);}#endif//    p->quality= (32 + a->inv_qscale/2)/a->inv_qscale;//    memset(p->qscale_table, p->quality, p->qstride*a->mb_height);        *picture= *(AVFrame*)&a->picture;    *data_size = sizeof(AVPicture);    emms_c();        return (get_bits_count(&a->gb)+31)/32*4;}