static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
    DelogoContext *s = inlink->dst->priv;
    AVFilterLink *outlink = inlink->dst->outputs[0];
    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
    AVFrame *out;
    int hsub0 = desc->log2_chroma_w;
    int vsub0 = desc->log2_chroma_h;
    int direct = 0;
    int plane;
    AVRational sar;

    if (av_frame_is_writable(in)) {
        direct = 1;
        out = in;
    } else {
        out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
        if (!out) {
            av_frame_free(&in);
            return AVERROR(ENOMEM);
        }

        av_frame_copy_props(out, in);
    }

    sar = in->sample_aspect_ratio;
    /* Assume square pixels if SAR is unknown */
    if (!sar.num)
        sar.num = sar.den = 1;

    for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++) {
        int hsub = plane == 1 || plane == 2 ? hsub0 : 0;
        int vsub = plane == 1 || plane == 2 ? vsub0 : 0;

        apply_delogo(out->data[plane], out->linesize[plane],
                     in ->data[plane], in ->linesize[plane],
                     FF_CEIL_RSHIFT(inlink->w, hsub),
                     FF_CEIL_RSHIFT(inlink->h, vsub),
                     sar, s->x>>hsub, s->y>>vsub,
                     /* Up and left borders were rounded down, inject lost bits
                      * into width and height to avoid error accumulation */
                     FF_CEIL_RSHIFT(s->w + (s->x & ((1<<hsub)-1)), hsub),
                     FF_CEIL_RSHIFT(s->h + (s->y & ((1<<vsub)-1)), vsub),
                     s->band>>FFMIN(hsub, vsub),
                     s->show, direct);
    }

    if (!direct)
        av_frame_free(&in);

    return ff_filter_frame(outlink, out);
}
The software performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer.