VMC

VMC is an acronym that can refer to several concepts depending on the field. This article highlights three common uses across different domains.

Visual Meteorological Conditions, in aviation, designate weather conditions that allow flight by visual reference to the outside environment. VMC are defined by minimum visibility and cloud clearance requirements and are contrasted with Instrument Meteorological Conditions (IMC). When weather stays within VMC, pilots may operate under visual flight rules; if conditions deteriorate below VMC minima, pilots must transition to instrument flight rules or delay operations.

Video Motion Compensation is a technique used in video compression to reduce temporal redundancy between frames. By estimating the motion of objects from one frame to the next and compensating for it, codecs can encode only the changes, improving efficiency. Video Motion Compensation is a core component of inter-frame prediction in standards such as MPEG and H.264/AVC, and can be implemented in software or hardware hardware accelerators.

Voltage Mode Control is an approach used to regulate the output of switching-mode power supplies. It relies on comparing a scaled output voltage to a reference and using the resulting error signal to modulate the switching duty cycle. This method is contrasted with current mode control, which regulates inductor current. Voltage mode control offers certain design trade-offs in response time, stability, and load regulation.

In addition to these technical meanings, VMC can denote organizations, products, or project names that use the acronym. Because the meaning of VMC is highly context-dependent, it is best to determine the intended sense from accompanying fields or terminology.