Lip Sync issues - Sky Stream

[Chris4Stream]

I agree with what you are saying.

But what I am saying is that NOW TV and FireTV sticks could be using different audio formats and therefore different delays.

That's my point, its such a complicated matter.

In fact, look through these forums, the fix seems to be to use PCM audio format to fix the issue, and most SKY Stream users report this does fix it, my point is that the NOW TV and FireTV Sticks that users are probably saying work fine are using PCM.... say audio formay, say Ms delay....

[Chris4Stream]

say=same

I can't even edit mu own post!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

That U SKY FORUMS

[Chris4Stream]

I've done some googling and I think the default audio output from a FireTV Stick is PCM, in that case unless a user changes it they will see no lipsync issue with a soundbar, and same as if they select PCM on the SKY Stream Box.

With PCM there is NO sound processing on the Soundbar and hence NO sound delay.

Its a complex matter

[Jonny16]

The default audio for Firestick is Auto which will automatically select the best format.

Many of the people reporting issues are quite savvy and use soundbars, 5.1 setup, AV receivers etc and can change and experiment with audio settings. You'll find most people who don't see the issues just use their own TV speakers for the sound.

I have now tv via a Firestick and it isn't PCM, I get the Dolby Atmos with the soundbar and no lip sync issues. Ironically I did have issues with my brief experience with Sky stream.

Like you say it's very complex, but from experience and from other detailed responses online that I've seen, a lot of the problems are with these pucks. 

[Chris4Stream]

@Jonny16 

Everything I say might be crap.

I'm not an expert, but Im trying to help.

I think the more we all discuss the issue the better we feel supported????

I would love SKY to pop in every now an again and say something....

[Chris4Stream]

Its the same for SKY Stream, select AUTO, it's PCM....

[Chris4Stream]

PCM, there is no processing on the Audio device

[TechMaster]

I have a lg OLED c3 with sky stream and eArc to a sound bar but set everything to pass through on the stream box and the tv hdmi settings , I basically disable all the possible audio processing the steam box or tv could do and just pass the raw audio to my sound bar. No lip sync isssus at all.

[Skull+Treaty]

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@TechMaster wrote:

I have a lg OLED c3 with sky stream and eArc to a sound bar but set everything to pass through on the stream box and the tv hdmi settings , I basically disable all the possible audio processing the steam box or tv could do and just pass the raw audio to my sound bar. No lip sync isssus at all.

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@TechMaster 

Have you tried watching the Food Network channel (or whatever it's called)? 
It is the only channel that I get lip sync issues with, horrendous! A flick of the channel up or down then back resolves it. 
We don't watch the channel much, only around the festive period. 

[Fothergill1]

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@Chris4Stream wrote:

say=same

I can't even edit mu own post!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

That U SKY FORUMS

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@Chris4Stream Forum member are able to edit their own posts once they reach level 3 so you CAN edit your posts 😀 but it needs to be done within a certain time frame.  I'm not sure what that is but it seems to be around 30 to 60 minutes or thereabouts.   

In order to edit go to the 3 dots on the top right corner of your post (next to the date & time) and click on it and then you will get a drop down menu.  If you are still within the time limit to edit it you will see it as the top option.  If it says "mark as new" you are outside of the editing time window.

EDIT - I still don't know the time frame for editing replies but I have just seen that a post a made just over 2 hours ago still has the option of editing available so it is much longer than I thought.

[TechMaster]

@Skull+Treaty No I haven't but I just just flicked over to it for 5 mins and it was fine, no issues. Maybe I need to leave it a bit longer to test

[Skull+Treaty]

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@TechMaster wrote:

@Skull+Treaty No I haven't but I just just flicked over to it for 5 mins and it was fine, no issues. Maybe I need to leave it a bit longer to test

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@TechMaster 
I think it's happened after returning from an ad break. 
Similar to you, TV & Stream are set to pass through and not had any issues on any other channel. 

[TechMaster]

@Skull+Treaty ok I will try it for a bit longer. 

for my setup on my TV I also set the HDMI Audio format to bitstream, and I have an option called match screen and sound which which I set to bypass. 

I also duplicated those settings to my hdmi 2 eArc port even though that just has the soundbar on it, as I was getting a weird issue with Disney plus not outputting Atmos via the steam box, matching the setting onto hdmi 2 fixed that issue (but that's another story)

[Littletaffia]

@Chris4Stream You are correct about PCM that there is no decoding but it still has to be converted from a digital signal to analogue. Sky want you to use PCM because their default is stereo and not multi channel. Other streaming service use multi channel PCM like the basic 5.1 channels on Paramount. Dolby Digital Plus is used when there is Atmos metadata attached.

With PCM multi channel I also engage DTS Neural:X to bring in my Atmos speakers so the whole packet of data is being processed so taking your theory to it's extent then I should be experiencing delay even with an initial delivery of PCM. This doesn't happen with my Denon AVR. Perhaps it's better processor. With a base Dolby Digital 5.1 I still engage Dolby Surround. Yet I still get perfect lip sync when using the Apple TV. Sky were more than happy to blame my Denon for the lip sync problems. 

I know that Apple did have, may still do on some pucks, but I believe this has been resolved with the newer 4th generation puck that I have. I did hold back on getting a puck because of these issues prior to the 4th gen being released. The older generations being updated by firmware.

Now your talking about HDMI communication, the infamous handshake. I do agree that HDMI is a complete balls up but it's what we have and software and hardware has to work within those constraints. Enhanced ARC was supposed to have solved audio issues, amongst other gremlins, but a lot seem to still exist. I'm not using ARC because all of my connections are direct to the Denon. 

There are obviously problems with Sky transmitting Dolby over bitstream hence their request for subscribers to use stereo PCM which requres less bandwidth. So the clock is out most likely on the puck and is not communicating properly with either the soundbar or AVR. Bitstream have clock embedded into the audio stream and it's obviously running behind the video so when it gets picked up by the soundbar or AVR it gets acknowedged but at the wrong time. That's before the processing can begin. The AVR can only acknowledge the timing from the sending device and sync to that signal. If the clock is slightly in front of the video then that's easily taken care of by delaying that audio. If it's behind, which it is, then that cannot be defeated.

Sky Stream and Glass must have more bugs that a David Attenborough programme.

[Zoltron]

The issue is Glass is also affected, I see just as many issues on my Glass TV downstairs as I see on my puck upstairs which is connected to a 70" Philips TV and Sonos Arc.

The issue is there is a relatively easy fix which has been used by PC's for a long time which could be used to fix this, regardless of whether it's the audio or video first, the fix is to have a buffer, by having a buffer the audio can then be shifted in either direction by the user. Whether this kind of implementation is possible on existing hardware is a question for the development teams to answer. Glass and stream must have some limited storage capacity, but whether there is enough storage capacity to buffer 5-10 seconds of UHD video will need to be looked into.

But I don't think this is necessary, because this lip sync issue is a new problem which has only recently come about.

The question is, what has changed? Is it firmware or the broadcast stream?

I'll stick my money on firmware, as I've only noticed the issue on my Glass and Puck since the AirPlay update.