True or False HDMI 2.1? Difference between HDMI TMDS and FRL

Radiohead

Member
HDMI 2.1 has two sets of protocols, the TMDS and the FRL. This originated when the HDMI Forum eliminated the concept of HDMI 2.0 and chose to replace the original HDMI 2.0 with the HDMI 2.1 TMDS protocol.

HDMI 2.1.jpg


With the development of TV technology, more and more TV products on the market will be 4K, HDMI2.1 as the "standard". But in fact, HDMI2.1 is divided into HDMI TMDS and HDMI FRL two protocol modes, which means that what you think HDMI2.1 may not really HDMI2.1.

Such as some TV product parameters page will show equipped with "HDMI2.1 interface x2", while the note "HDMI2.1 interface of this product supports TMDS protocol". Next, this article will bring you true and false HDMI2.1 comparison, let's take a look at the difference of TMDS and FRL protocol in HDMI2.1.

HDMI 2.1 has two sets of protocols, the TMDS protocol and the FRL protocol. This originated when the HDMI Forum eliminated the concept of HDMI 2.0 and chose to replace the original HDMI 2.0 with the HDMI 2.1 TMDS protocol.

Among them, HDMI 2.1 FRL is the original standard HDMI 2.1, which theoretically supports 48Gbps bandwidth, while HDMI 2.1 TMDS is 18Gbps bandwidth. This is also the biggest difference between the original HDMI 2.0 and HDMI 2.1. Therefore, strictly speaking, HDMI 2.1 TMDS is not really HDMI 2.1.

According to the rules of HDMI Forum, not all HDMI 2.0 can be renamed to HDMI 2.1 TMDS, but those that support eARC (Enhanced Audio Return Channel) can be successfully renamed, otherwise they will be downgraded to HDMI 1.4b. But in the consumer electronics market, there will still be some TV products that do not support eARC forcibly upgraded to HDMI 2.1 logo.

When buying a TV, we must pay attention to which protocol mode is used for HDMI 2.1, only HDMI FRL is the standard HDMI 2.1 interface, which will bring sound and picture gain to gamers.
 

Lily15

Member
when you buy a TV for playing games, the true HDMI 2.1 is important, so it's good to know the traps in advance
 
As its name suggests, FRL means Fixed Rate Link. FRL Lane 0, Lane 1, Lane 2, and Lane 3 correspond to TMDS Clock, Data 0, Data 1, and Data 2. Since FRL does not require a clock channel as TMDS does, FRL uses four pairs of lanes instead of three to transfer data.
 
FRL stands for Fixed Rate Link and it's a signaling technology supported in the HDMI 2.1a Specification. FRL is necessary to achieve the higher uncompressed resolutions such as those above 4k60 as well as the ultra high speed bandwidths up to 48Gbps.
 
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