The point being Kev that you were decoding surround in the player... PCM stands for 'Pulse code Modulation'; It's just uncompressed (or decompressed) digital audio. - In this particular case it's the de-compressed and decoded (into stereo) feed that would then go to the sets internal D>A converter and from there drive the analogue amplifers and speakers...
There are no lip-sync problems on PCM because that Is basically what is being fed to the set's speakers and the set is built around that...
This set has no surround sound decoding or capability (CODECS need licensing!) - so, if you have a proper surround amplifier, and you need IT to do what it's supposed to do - you need to pass the compressed (i.e. 'not decoded') stream straight through to the A/V amp, seperate decoder or whatever... And this is what the first two modes in the audio set up do...
Interestingly, where the broadcasters transmit surround, - if the set is switched to mode '2' so that it outputs PCM unless it detects a surround stream it will send that signal (usually Dolby) to the amp with no lip-sync problems. - I've no interest in streaming services so haven't tried it; but presumably the set would also be 'OK' on those....
But it's on HDMI inputs where the problem lies... These sets introduce a delay (certainly through the optical output) which causes the picture to lead the sound... It's called latency! It's especially bad on DTS and can actually vary from disc-to-disc and/or player-to player... I've tried about 1/2 dozen from different manufacturers...
Though again (oddly) an Echostar HDR/tuner passing though Dolby has little or no problem!
The 'delay' facility on the amp can't help... Because of course the PICTURE is leading...
In my own case I've no facility to use ARC - Which seems (having now tried the set with a few audio devices) to be very hit-and-miss in any case... I found a few new-ish soundbars that it wouldn't work with too...
A 'soundbar' is basically just a couple of speakers and an amp in a box... It's primary purpose is to compensate for the fact you cannot physically produce decent sound from the loudspeakers in modern sets due to the very restricted cabinet size... In years gone by some pretty rubbish speakers could be fitted inside a lovely chipboard box and made sound almost-respectable... But ye canny change the laws of physics! - Thus the 'soundbar' was born!
And is very much a necessity for any stand-alone TV setup IMHO!
Feeding a soundbar PCM will be fine... Just as you can't physically fit a Volvo inside a Mini, you cannot physically create surround sound (as it was intended) without the proper speaker set-up... There are a few 'tricks' sounbars play to give pseudo-surround; but they are what they are...
However, for those that want to make full use of 'more complete' audio systems; these sets present SEVERE problems!
