I have my Nvidia 2019 shield connected directly to my LG CX tv. Then I have my Yamaha YAS209 soundbar connected via ARC to my TV. When I play any file that only has a DTS soundtrack in it, Plex says it’s direct playing it and there are no issues with the sound that I can tell. However, I thought the LG CX could not passthrough DTS. So I’m curious as to how it’s all working. Any ideas? Is the TV converting it to PCM 2.0 before passing it through to the soundbar?
I think you will find DTS is encoded PCM. PCM is in-compressed which is the key. Lossy compression like mp3 or m4a will mess up encoding like DTS. Some streaming services will also remove the encoding for a variety of reasons
Here is an interesting article.
When Plex Media Server shows Direct Play / Direct Stream / Transcode, that refers only to what is happening on the server. The Plex client (Shield) or the TV could be converting the audio to another format and the Plex server would not know it is happening.
LG does not support dts on the TV itself, however it is possible for the TV to passthrough unsupported audio formats from external sources to external sound equipment.
Edit: Added “external” to above sentence.
If your soundbar supports dts audio, it is possible the TV is passing the audio unaltered from the Shield through to the soundbar.
If the soundbar does not support dts audio, then either the Shield or the TV is converting it to a format accepted by the soundbar.
Thanks! I’m a noob when it comes to this stuff but am curious about things so trying to understand better how it all works. From what I read, the LG CX doesn’t passthrough DTS at all so that’s why I was asking how it’s working. I’m not complaining, just curious. I’m guessing it is getting converted somewhere in the chain. If that’s the case, am I losing anything sound-wise? The soundbar is a 2.1 so I’m guessing it really doesn’t matter either way?
I had it setup so the shield connected to the soundbar, but when I do that I don’t get Dolby Vision since the soundbar can’t pass it. So this is why I set it up so the shield connects directly to the TV and then the TV to the soundbar.
Well, I known Plex has their own AC3 decoder for android. So this allows files with 5.1 AC3 to be direct played. On the Android side, if you don’t choose PassThrough, the android app decodes the 5.1 AC3 to 5.1 PCM and sends it to the receiver. I suspect that they have their own DTS decoder as well. I’m sure someone from Plex can correct me if I’m wrong about that.
This isn’t really transcoding in the normal sense. We are just talking about whether the plex player decodes the format or the receiver does. A lot of people want the decoding to happen on the receiver because it may provide more processing options for the decoded sound. But you can get really good 5.1 sound to the receiver without passthrough – my old Android TV box did not support passthrough and I still got really good sound from my videos with 5.1 AC3. Obviously the receiver doesn’t know that the original format was AC3 – all it knows is that it is getting 5.1 PCM.
Obviously, you have to be using hdmi to the receiver to send 5.1 PCM since an optical cable doesn’t have the capacity for that.
Just found out some new (to me) information.
The 2020+ LG TVs will not passthrough dts audio formats from external devices. They do support passthrough of TrueHD audio.
I was under the impression that dts would passthrough, even if the TV could not decode it, since it is simply passing it on to another device.
So, with regard to your original post, what I wrote about the server showing direct play is still correct. The server shows direct play because it is not converting the audio.
However, the dts audio is definitely being converted by either the Shield or the TV to another format. The TV is not passing dts to the soundbar.
Apologies for the misinformation.
I confirmed yesterday that Plex For Android has its own DTS decoder like it does for AC3. This is why the player can direct play DTS without transcoding. I know lots of people prefer to have the receiver do the decoding – I’m not looking to have a philosophical discussion about that. I’m just explaining that the DTS can be direct played by the player and there is no loss in quality since the sound is never decompressed and then recompressed.
Again, all bets are off if you are sending sound to the the receiver through optical instead of hdmi since optical can only carry 2 channel PCM.
Thanks good to know. So is it that the Shield knows the TV can’t passthrough DTS and converts it? But for dolby it just passes it through? It’s hard to tell since the soundbar doesn’t give any indication of what it’s playing.
Most receivers have some sort of way of displaying the details of the current signal. Mine definitely tells me when it’s getting 5.1 PCM, DD, DD+ or DTS.
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