HDMI2.2 LIP Explained: A Massive Update To Deferred Processing Technology

Compared to HDMI 2.1, HDMI 2.2 introduces the Latency Indication Protocol (LIP), designed to improve the synchronization of audio and video signals. This clearly demonstrates HDMI 2.2's commitment to further enhancing audio-video synchronization across the entire signal transmission chain.

In fact, LIP is not the only technology HDMI employs to address audio-video latency. Features such as ARC (introduced with HDMI 1.4 in 2009) and eARC (introduced with HDMI 2.1 in 2017) already incorporate "Lip Sync Correction" technology to manage audio-video synchronization.

Specific advantages of ARC and eARC

Compared to traditional digital coaxial or optical audio transmission methods, HDMI ARC and eARC offer significant advantages. The table below summarizes the key technical benefits: the ability to transmit higher-specification surround sound signals—supporting up to 192kHz, 24-bit, 32-channel uncompressed audio—as well as Dolby Atmos and DTS:X, and, crucially, Lip Sync Correction technology. Another advantage of ARC and eARC is that they allow audio signals to be transmitted via the TV to a home theater amplifier or soundbar, even when the playback device does not support dual HDMI outputs.

LIP in the HDMI 2.2 specification

The LIP (Latency Indication Protocol) is designed to address audio-video synchronization latency across the entire HDMI transmission chain. It is particularly suited for systems involving multiple connected devices—such as multi-hop configurations incorporating various signal sources, home theater amplifiers, and soundbars—by providing precise latency control. Its primary use cases are in video gaming and home theater environments.

Four different application scenarios for HDMI LIP：

In fact, as is evident from the various application scenarios of LIP technology discussed earlier, the LIP technology employed in HDMI 2.2 addresses the entire audio-video transmission loop, whereas the Lip Sync Correction technology found in ARC/eARC focuses solely on the audio return channel. It can be said that the HDMI 2.2 LIP technology offers a broader scope for latency optimization and involves a higher level of processing.