Optimize the YUV buffer copy a little bit to skip unnecessary operation.

    size_t dstYStride = mIsAdaptive ? mAdaptiveMaxWidth : mWidth;

    size_t dstUVStride = dstYStride / 2;

    size_t dstHeight = mIsAdaptive ? mAdaptiveMaxHeight : mHeight;

    uint8_t *dstStart = dst;

    for (size_t i = 0; i < dstHeight; ++i) {

        if (i < mHeight) {

    for (size_t i = 0; i < mHeight; ++i) {

         memcpy(dst, srcY, mWidth);

         srcY += srcYStride;

        }

         dst += dstYStride;

    }

    for (size_t i = 0; i < dstHeight / 2; ++i) {

        if (i < mHeight / 2) {

    dst = dstStart + dstYStride * dstHeight;

    for (size_t i = 0; i < mHeight / 2; ++i) {

         memcpy(dst, srcU, mWidth / 2);

         srcU += srcUStride;

        }

         dst += dstUVStride;

    }

    for (size_t i = 0; i < dstHeight / 2; ++i) {

        if (i < mHeight / 2) {

    dst = dstStart + (5 * dstYStride * dstHeight) / 4;

    for (size_t i = 0; i < mHeight / 2; ++i) {

         memcpy(dst, srcV, mWidth / 2);

         srcV += srcVStride;

        }

         dst += dstUVStride;

    }

}