Puzzled here. Sound seems always to be the poor relation in TVs. I have an up to date AV amp (HDMI, optical etc inputs) - so I don't need to consider the restrictions of any TV as I feed my Virgin box or Freesat box to my AV amp.
What do LGs support soundwise?
Am in the market for a new TV soon. Our 32" Panasonic is showing its age!
Mel
@hornetstinger is correct. If your sources go to the amp first then what audio formats the TV supports becomes irrelevant. However, it's common to find folk connecting HDMI to the TV first, then feeding audio out to an AV receiver or a soundbar. The audio connection could be optical/HDMI ARC or eARC. The reason for connecting to the TV first could be that the amp doesn't support gaming features such as Variable Refresh Rate (VRR) or 120Hz refresh or Auto Low Latency Mode (ALLM).
Standard HDMI ARC (not eARC) and optical both work the same way. You'll always have have support for
Stereo PCM. That provides your amp with either simple stereo or stereo with Dolby surround encoded within it. This is decoded as Dolby Pro-Logic II or Dolby Upscaler.
You'll also find it's pretty much universal to have
Dolby Digital (DD) in up to 5.1 supported by optical and std ARC. That'll take care of discrete surround sound from the HDTV tuner, and from streaming apps, and from Sky/Virgin.
The next stage up we see optical drop out of the race. This is where we get into Dolby Atmos audio from streaming apps and from things such as Sky UHD downloads. The Atmos signal is carried by
Dolby Digital Plus (DD+). Technically, optical is perfectly capable of carrying this signal too, but it is software blocked from doing so by the regulations around HDCP which is HDMI content protection.
Next we come to
DTS audio support. Here it's very much about what the TV manufacturer decides to support, and that's determined by the costs of licencing.
In the bulk of the TV market you'll find that manufacturers offer support for DTS in stereo (DTS 2.0) but nothing better. There are some exceptions amongst the TV manufacturers, and even occasions where the premium models support DD 5.1 but the entry and mid-level models only do DTS 2.0. Of course, exceptions work both ways. A case in point is LG. Up to the 2019 model range there was support for DTS in either 2.0 or 5.1 However, after that point LG dropped DTS support totally. Other brands of OLED may well support DTS. This is purely an issue between LG and DTS.
How the TV communicates its abilities is through the HDCP portion of the HDMI handshake when two or more devices are connected together. This sets a lowest common denominator level of signal support between the devices.
eARC was developed to get past the limit of standard only supporting lossy multichannel surround formats (DD and DTS). Where a TV doesn't artificially limit support then an eARC-equipped TV connected to an eARC-equipped amp/receiver will support all that optical and std ARC does but also multichannel HD audio in the forms of bitstream Dolby True HD and bitstream DTS-HD Master Audio.
As an example of a practical application, a PS5 console could be connected to say a Panasonic OLED which has 120Hz and VRR and ALLM, and then the eARC connection for sound could feed through from the TV to an eARC capable amp that doesn't support 120Hz or VRR for pass through.
eARC also allows a multichannel PCM connection. (Remember that std ARC only does stereo PCM.) Using multichannel PCM is a way to sidestep restrictions in DTS audio support within LG TVs.