if (s->h263_msmpeg4) if(msmpeg4_decode_ext_header(s, buf_size) < 0) return -1;
static int h263_decode_frame(AVCodecContext *avctx,                              void *data, int *data_size,                             UINT8 *buf, int buf_size){    MpegEncContext *s = avctx->priv_data;    int ret;    AVPicture *pict = data; #ifdef DEBUG    printf("*****frame %d size=%d\n", avctx->frame_number, buf_size);    printf("bytes=%x %x %x %x\n", buf[0], buf[1], buf[2], buf[3]);#endif        /* no supplementary picture */    if (buf_size == 0) {        *data_size = 0;        return 0;    }    init_get_bits(&s->gb, buf, buf_size);    /* let's go :-) */    if (s->h263_msmpeg4) {        ret = msmpeg4_decode_picture_header(s);    } else if (s->h263_pred) {        ret = mpeg4_decode_picture_header(s);    } else if (s->h263_intel) {        ret = intel_h263_decode_picture_header(s);    } else {        ret = h263_decode_picture_header(s);        /* After H263 header decode we have the height, width,       */        /* and other parameters. So then we could init the picture   */        /* FIXME: By the way H263 decoder is evolving it should have */        /* an H263EncContext                                         */        if (!s->context_initialized) {            avctx->width = s->width;            avctx->height = s->height;            if (MPV_common_init(s) < 0)                return -1;        } else if (s->width != avctx->width || s->height != avctx->height) {            /* H.263 could change picture size any time */            MPV_common_end(s);            if (MPV_common_init(s) < 0)                return -1;        }    }    if (ret < 0)        return -1;    MPV_frame_start(s);#ifdef DEBUG    printf("qscale=%d\n", s->qscale);#endif    /* decode each macroblock */    for(s->mb_y=0; s->mb_y < s->mb_height; s->mb_y++) {        /* Check for GOB headers on H.263 */        /* FIXME: In the future H.263+ will have intra prediction */        /* and we are gonna need another way to detect MPEG4      */        if (s->mb_y && !s->h263_pred) {            s->first_gob_line = h263_decode_gob_header(s);        }        for(s->mb_x=0; s->mb_x < s->mb_width; s->mb_x++) {#ifdef DEBUG            printf("**mb x=%d y=%d\n", s->mb_x, s->mb_y);#endif            //fprintf(stderr,"\nFrame: %d\tMB: %d",avctx->frame_number, (s->mb_y * s->mb_width) + s->mb_x);            /* DCT & quantize */            if (s->h263_msmpeg4) {                msmpeg4_dc_scale(s);            } else if (s->h263_pred) {                h263_dc_scale(s);            } else {                /* default quantization values */                s->y_dc_scale = 8;                s->c_dc_scale = 8;            }#ifdef HAVE_MMX            if (mm_flags & MM_MMX) {                asm volatile(			"pxor %%mm7, %%mm7		\n\t"			"movl $-128*6, %%eax		\n\t"			"1:				\n\t"			"movq %%mm7, (%0, %%eax)	\n\t"			"movq %%mm7, 8(%0, %%eax)	\n\t"			"movq %%mm7, 16(%0, %%eax)	\n\t"			"movq %%mm7, 24(%0, %%eax)	\n\t"			"addl $32, %%eax		\n\t"			" js 1b				\n\t"			: : "r" (((int)s->block)+128*6)			: "%eax"                );            }else{                memset(s->block, 0, sizeof(s->block));            }#else            memset(s->block, 0, sizeof(s->block));#endif            s->mv_dir = MV_DIR_FORWARD;            s->mv_type = MV_TYPE_16X16;             if (s->h263_msmpeg4) {                if (msmpeg4_decode_mb(s, s->block) < 0)                    return -1;            } else {                if (h263_decode_mb(s, s->block) < 0) {                    fprintf(stderr,"\nError at MB: %d\n", (s->mb_y * s->mb_width) + s->mb_x);                    return -1;                }            }            MPV_decode_mb(s, s->block);        }        if (avctx->draw_horiz_band) {            UINT8 *src_ptr[3];            int y, h, offset;            y = s->mb_y * 16;            h = s->height - y;            if (h > 16)                h = 16;            offset = y * s->linesize;            src_ptr[0] = s->current_picture[0] + offset;            src_ptr[1] = s->current_picture[1] + (offset >> 2);            src_ptr[2] = s->current_picture[2] + (offset >> 2);            avctx->draw_horiz_band(avctx, src_ptr, s->linesize,                                   y, s->width, h);        }    }    MPV_frame_end(s);        pict->data[0] = s->current_picture[0];    pict->data[1] = s->current_picture[1];    pict->data[2] = s->current_picture[2];    pict->linesize[0] = s->linesize;    pict->linesize[1] = s->linesize / 2;    pict->linesize[2] = s->linesize / 2;    avctx->quality = s->qscale;    *data_size = sizeof(AVPicture);    return buf_size;}