libavfilter/vf_gradfun.c:223: error: Uninitialized Value
  The value read from direct was never initialized.

libavfilter/vf_gradfun.c:223:10: 
221.     }
222. 
223.     if (!direct)
              ^
224.         avfilter_unref_bufferp(&in);
225. 

static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *in)
{
    GradFunContext *gf = inlink->dst->priv;
    AVFilterLink *outlink = inlink->dst->outputs[0];
    AVFilterBufferRef *out;
    int p, direct;
    if ((in->perms & AV_PERM_WRITE) && !(in->perms & AV_PERM_PRESERVE)) {
        direct = 1;
        out = in;
    } else {
        out = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);
        if (!out) {
            avfilter_unref_bufferp(&in);
            return AVERROR(ENOMEM);
        }
        avfilter_copy_buffer_ref_props(out, in);
        out->video->w = outlink->w;
        out->video->h = outlink->h;
    }
    for (p = 0; p < 4 && in->data[p]; p++) {
        int w = inlink->w;
        int h = inlink->h;
        int r = gf->radius;
        if (p) {
            w = gf->chroma_w;
            h = gf->chroma_h;
            r = gf->chroma_r;
        }
        if (FFMIN(w, h) > 2 * r)
            filter(gf, out->data[p], in->data[p], w, h, out->linesize[p], in->linesize[p], r);
        else if (out->data[p] != in->data[p])
            av_image_copy_plane(out->data[p], out->linesize[p], in->data[p], in->linesize[p], w, h);
    }
    if (!direct)
        avfilter_unref_bufferp(&in);
    return ff_filter_frame(outlink, out);
}
['static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *in)\n{\n    GradFunContext *gf = inlink->dst->priv;\n    AVFilterLink *outlink = inlink->dst->outputs[0];\n    AVFilterBufferRef *out;\n    int p, direct;\n    if ((in->perms & AV_PERM_WRITE) && !(in->perms & AV_PERM_PRESERVE)) {\n        direct = 1;\n        out = in;\n    } else {\n        out = ff_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h);\n        if (!out) {\n            avfilter_unref_bufferp(&in);\n            return AVERROR(ENOMEM);\n        }\n        avfilter_copy_buffer_ref_props(out, in);\n        out->video->w = outlink->w;\n        out->video->h = outlink->h;\n    }\n    for (p = 0; p < 4 && in->data[p]; p++) {\n        int w = inlink->w;\n        int h = inlink->h;\n        int r = gf->radius;\n        if (p) {\n            w = gf->chroma_w;\n            h = gf->chroma_h;\n            r = gf->chroma_r;\n        }\n        if (FFMIN(w, h) > 2 * r)\n            filter(gf, out->data[p], in->data[p], w, h, out->linesize[p], in->linesize[p], r);\n        else if (out->data[p] != in->data[p])\n            av_image_copy_plane(out->data[p], out->linesize[p], in->data[p], in->linesize[p], w, h);\n    }\n    if (!direct)\n        avfilter_unref_bufferp(&in);\n    return ff_filter_frame(outlink, out);\n}']