int avcodec_default_get_buffer(AVCodecContext *s, AVFrame *pic){

    int i;

    int w= s->width;

    int h= s->height;

    InternalBuffer *buf;

    int *picture_number;



    assert(pic->data[0]==NULL);

    assert(INTERNAL_BUFFER_SIZE > s->internal_buffer_count);



    if(avcodec_check_dimensions(s,w,h))

        return -1;



    if(s->internal_buffer==NULL){

        s->internal_buffer= av_mallocz(INTERNAL_BUFFER_SIZE*sizeof(InternalBuffer));

    }

#if 0

    s->internal_buffer= av_fast_realloc(

        s->internal_buffer,

        &s->internal_buffer_size,

        sizeof(InternalBuffer)*FFMAX(99,  s->internal_buffer_count+1)

        );

#endif



    buf= &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];

    picture_number= &(((InternalBuffer*)s->internal_buffer)[INTERNAL_BUFFER_SIZE-1]).last_pic_num; 

    (*picture_number)++;



    if(buf->base[0]){

        pic->age= *picture_number - buf->last_pic_num;

        buf->last_pic_num= *picture_number;

    }else{

        int h_chroma_shift, v_chroma_shift;

        int pixel_size, size[3];

        AVPicture picture;



        avcodec_get_chroma_sub_sample(s->pix_fmt, &h_chroma_shift, &v_chroma_shift);



        avcodec_align_dimensions(s, &w, &h);



        if(!(s->flags&CODEC_FLAG_EMU_EDGE)){

            w+= EDGE_WIDTH*2;

            h+= EDGE_WIDTH*2;

        }

        avpicture_fill(&picture, NULL, s->pix_fmt, w, h);

        pixel_size= picture.linesize[0]*8 / w;



        assert(pixel_size>=1);

            

        if(pixel_size == 3*8)

            w= ALIGN(w, STRIDE_ALIGN<<h_chroma_shift);

        else

            w= ALIGN(pixel_size*w, STRIDE_ALIGN<<(h_chroma_shift+3)) / pixel_size;

        size[1] = avpicture_fill(&picture, NULL, s->pix_fmt, w, h);

        size[0] = picture.linesize[0] * h;

        size[1] -= size[0];

        if(picture.data[2])

            size[1]= size[2]= size[1]/2;

        else

            size[2]= 0;



        buf->last_pic_num= -256*256*256*64;

        memset(buf->base, 0, sizeof(buf->base));

        memset(buf->data, 0, sizeof(buf->data));



        for(i=0; i<3 && size[i]; i++){

            const int h_shift= i==0 ? 0 : h_chroma_shift;

            const int v_shift= i==0 ? 0 : v_chroma_shift;



            buf->linesize[i]= picture.linesize[i];



            buf->base[i]= av_malloc(size[i]+16); 

            if(buf->base[i]==NULL) return -1;

            memset(buf->base[i], 128, size[i]);



            

            if((s->flags&CODEC_FLAG_EMU_EDGE) || (s->pix_fmt == PIX_FMT_PAL8) || !size[2])

                buf->data[i] = buf->base[i];

            else

                buf->data[i] = buf->base[i] + ALIGN((buf->linesize[i]*EDGE_WIDTH>>v_shift) + (EDGE_WIDTH>>h_shift), STRIDE_ALIGN);

        }

        pic->age= 256*256*256*64;

    }

    pic->type= FF_BUFFER_TYPE_INTERNAL;



    for(i=0; i<4; i++){

        pic->base[i]= buf->base[i];

        pic->data[i]= buf->data[i];

        pic->linesize[i]= buf->linesize[i];

    }

    s->internal_buffer_count++;



    return 0;

}
