static void end_frame(AVFilterLink *inlink)
{
    TransContext *trans = inlink->dst->priv;
    AVFilterBufferRef *inpic  = inlink->cur_buf;
    AVFilterBufferRef *outpic = inlink->dst->outputs[0]->out_buf;
    AVFilterLink *outlink = inlink->dst->outputs[0];
    int plane;

    for (plane = 0; outpic->data[plane]; plane++) {
        int hsub = plane == 1 || plane == 2 ? trans->hsub : 0;
        int vsub = plane == 1 || plane == 2 ? trans->vsub : 0;
        int pixstep = trans->pixsteps[plane];
        int inh  = inpic->video->h>>vsub;
        int outw = outpic->video->w>>hsub;
        int outh = outpic->video->h>>vsub;
        uint8_t *out, *in;
        int outlinesize, inlinesize;
        int x, y;

        out = outpic->data[plane]; outlinesize = outpic->linesize[plane];
        in  = inpic ->data[plane]; inlinesize  = inpic ->linesize[plane];

        if (trans->dir&1) {
            in +=  inpic->linesize[plane] * (inh-1);
            inlinesize *= -1;
        }

        if (trans->dir&2) {
            out += outpic->linesize[plane] * (outh-1);
            outlinesize *= -1;
        }

        for (y = 0; y < outh; y++) {
            switch (pixstep) {
            case 1:
                for (x = 0; x < outw; x++)
                    out[x] = in[x*inlinesize + y];
                break;
            case 2:
                for (x = 0; x < outw; x++)
                    *((uint16_t *)(out + 2*x)) = *((uint16_t *)(in + x*inlinesize + y*2));
                break;
            case 3:
                for (x = 0; x < outw; x++) {
                    int32_t v = AV_RB24(in + x*inlinesize + y*3);
                    AV_WB24(out + 3*x, v);
                }
                break;
            case 4:
                for (x = 0; x < outw; x++)
                    *((uint32_t *)(out + 4*x)) = *((uint32_t *)(in + x*inlinesize + y*4));
                break;
            }
            out += outlinesize;
        }
    }

    ff_draw_slice(outlink, 0, outpic->video->h, 1);
    ff_end_frame(outlink);
    avfilter_unref_buffer(outpic);
}