Quick Media Switching (QMS)
HDMI® Quick Media Switching (QMS)
HDMI 2.1 features Quick Media Switching for movies and video which eliminates the delay that can result in blank screens before content is displayed. QMS uses the VRR mechanism to eliminate the blackout period when all devices in the HDMI connection chain change video modes. As long as the resolution remains the same and only the frame rate changes, QMS will smoothly switch between frame rates.
For example, when looking at trailers from a streaming service, some may be in 24Hz, 50Hz, or 60Hz. Every time a trailer with a different frame rate is selected, the entire system must change its clocking and re-sync, causing an A/V blackout (a “bonk”). Knowing that a change-of-video mode causes bonks, streaming services may compensate and add a built-in delay so that users don’t miss the first part of the trailer. Or they may output everything at the same frame rate which requires either the streaming service to provide single-frequency streams or the streaming box to perform the conversion.
QMS eliminates bonks by using the VRR mechanism to change frame rates, allowing rapid, smooth changes from a nominal 60Hz rate to any media rate below it (down to 24Hz). The viewer never sees blank screens and gets a seamless experience.
HDMI® Licensing Administrator, Inc. (HDMI LA) is the agent appointed by the HDMI Forum to license Version 2.1 of the HDMI Specification and is the agent appointed by the HDMI Founders to license all earlier HDMI Specifications.
USAHDMI® Licensing Administrator, Inc.
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