How to Improve the Speed of Scanning and focus of Qr Code?

Question

I am using Zing Library for scan Qr code.

  case ZXING_LINK:
    if (scanFromWebPageManager == null || !scanFromWebPageManager.isScanFromWebPage()) {
      handleDecodeInternally(rawResult, resultHandler, barcode);
    } else {
      handleDecodeExternally(rawResult, resultHandler, barcode);
    }

I want to Improve the Speed of scanning and focus. it takes time to focus and scan.