My settings

encodersettings.cpp

    out->enc->codec_id = codec->id;

    out->enc->bit_rate = 400000;
    out->enc->width = res.width() % 2 ? res.width() - 1 : res.width();
    out->enc->height = res.height() % 2 ? res.height() - 1 : res.height();
    size = QSize(out->enc->width, out->enc->height);
    out->st->time_base = { 1, fps };
    out->enc->time_base = out->st->time_base;

    out->enc->gop_size = 12;
    out->enc->pix_fmt = AV_PIX_FMT_YUV420P;
    if (out->enc->codec_id == AV_CODEC_ID_MPEG2VIDEO)
        out->enc->max_b_frames = 2;
    else if (out->enc->codec_id == AV_CODEC_ID_MPEG1VIDEO)
        out->enc->mb_decision = 2;