static int config_input_main(AVFilterLink *inlink)
{
    OverlayContext *s = inlink->dst->priv;
    const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
    av_image_fill_max_pixsteps(s->max_plane_step, NULL, pix_desc);
    s->hsub = pix_desc->log2_chroma_w;
    s->vsub = pix_desc->log2_chroma_h;
    return 0;
}
['static int config_input_main(AVFilterLink *inlink)\n{\n    OverlayContext *s = inlink->dst->priv;\n    const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);\n    av_image_fill_max_pixsteps(s->max_plane_step, NULL, pix_desc);\n    s->hsub = pix_desc->log2_chroma_w;\n    s->vsub = pix_desc->log2_chroma_h;\n    return 0;\n}', 'const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)\n{\n    if (pix_fmt < 0 || pix_fmt >= AV_PIX_FMT_NB)\n        return NULL;\n    return &av_pix_fmt_descriptors[pix_fmt];\n}']