It’s likely a Samsung TV issue - many modern TV manufacturers have introduced ‘pass-through’ across their ports, so that the TV does not process the audio and cause delay, but simply lets it bypass the TV. The Sonos speakers can only ever play the audio when it’s been received and that clearly happens with most brand/models of TV - a workaround for TV’s that cannot process the audio quickly enough is to use an external audio splitter and bypass the TV altogether, as widely discussed in many audio community forums online, including this forum.

Nothing to do with Sonos.  It’s your TV that is at fault, delaying the passthrough of the audio so you get lip sync issues.

Hilarious. You blame everybody but the real culprit, which is Samsung.

Route the audio round the TV using a device like the HDFury Arcana.

Wait…you’re saying Sonos is not going to invent a time machine so that it can play the stream before it is received from the TV?

Here’s a Flux Capacitor, which may work perhaps, which I have posted here the day after tomorrow:

My understanding was the passthrough options were introduced so that bitstream decoding could be processed downstream to preserve (perceived) quality, rather than being an issue with processing delay. Similar I guess to aspirational bit-perfection in the HI-FI domain. Typically the picture processing is the more CPU intensive and the usual cause of noticeable delays? I have seen this issue first hand with the Sky Q box (not sure what the OP has) and I’d be surprised if the TV audio transcoding processing was introducing almost a 1 second delay in the audio stream.

https://www.samsung.com/sg/support/tv-audio-video/what-is-hdmi-pass-through/

Only a dolby bitstream blu-ray as the source doesn’t suffer from lip sync. Sky forums report lip-sync issues with Q and multiple soundbar/TV manufacturers. Maybe check through the missing details with OP before ganging up and goading them, doesn’t really help anyone coming here to look for a solution.

Sky forum does report success with the Arcana however, but it’s relatively expensive and impractical for more than once source (before adding an HDMI switch on top I think I would pack in the ARC altogether and buy an AV receiver). My gut feeling is a bug in the lip-sync ARC protocol in the Q box, but whatever. The stream pucks are now available to order standalone from glass, I’m wondering if they behave any better.

If that was the case it would not explain why the Arcana solves the issue for those who opt to bypass their TV sets when using Sky Q. I accept the Arcana is expensive, but there are cheaper alternatives (with built-in switch) such as the Feintech VAX04101A or OREI HDA-931, to name but two. I use the VAX04101A myself in fact.

Could be, but doesn’t seem unreasonable that ARC users want the devices they already own to work with the Q box in a similar way to other sources (albeit that I also doubt the issue is with Sonos) and not need to buy additional hardware just to enable usable Sky Dolby.

I don’t know anything about how those channel splitter devices actually work. Was assuming they isolate the audio and video devices by presenting the source with a dummy TV endpoint (a bit like computer KVMs) which also prevents any meaningful lip-sync protocol negotiation (which in any case would conflict with the intended outcome even if just trying to bypass the processing lag?) therefore avoiding triggering my theoretical bug in the Q box.

Or more crudely, maybe the Arcana just blocks any lip-sync messages reaching the Q box from the TV? Does passthrough setting on the TV block auto lip-sync anyway? I don’t know.

https://www.avsforum.com/threads/how-the-hell-does-hdmis-auto-lip-sync-work.1160970/

Maybe there are some auto lip-sync settings that can be turned off on the devices to prove/disprove the point, I’ll try next time I have access. 

Either way, the Q box seems to introduce a delay in Dolby (e)ARC audio when other sources do not, which rules out audio transcoding processing delay for me assuming it would be the same for all HDMI inputs. Introducing the Arcana then corrects the problem somehow.

The Q box used to be connected directly to an AV receiver, so no ARC (HDMI or Sonos!) and I don’t remember there being a lag for dolby in that setup. If it did, I could consider that the Q box just delayed all Dolby output, but don’t think that’s the case either.

Of course, if the TV is buggy and my bluray player simply doesn’t implement lip sync delay, then maybe the Q box is behaving correctly. Could take a while to validate that...

Earlier you referred to a HT ‘Receiver’ link when talking about audio pass-through, however I’m referring to the main TV audio pass-through as the main A/V master device here that would otherwise process the video to its screen and transcode the audio out through its ports - the Sonos HT product does not transcode any audio - it just plays the ‘returned’ audio sent, as soon as it arrives, with virtually little, or no, delay.

The audio delay experienced in this instant is ‘clearly’ either the sending device (Sky Q Box), or the OP’s Samsung TV. The evidence points to it being the Samsung TV, because (a) it will transcode the audio received (it does not have pass-through) and (b) it’s clear that if the Sky Q audio is re-routed to bypass the TV and ‘pass-through’ the Arcana, which ‘splits’ (diverts) the audio track from the A/V signal and directs it (quickly/no transcoding) to the Sonos Arc - it will then play all in perfect lip-sync with the video on the TV screen - there is no delay when the audio signal merely bypasses the TV ports, so that shows/infers the Samsung TV is the issue and it’s been discussed before in other threads here in the community. In fact older Samsung TV’s are often mentioned in such threads. 

The OP, despite those past threads, was clearly trying to say the issue should be fixed by Sonos, but the evidence in most cases tends to show it’s not actually a Sonos issue - it’s usually the TV, or the A/V sending device. In this case the evidence points more towards it being the Samsung TV - that’s the point I’m simply trying to highlight here. 

I got so frustrated with Samsung on this issue that I sold it and bought a Panasonic and had no problems since. Will never get another Samsung, they know it’s an issue but have done nothing to resolve it. 

I don’t have Samsung TV, but I do sometimes get lip sync issues on Sky live UHD feeds, eg F1

There is a technical doc here I found a while back, I think I may have posted on here before:

Sky Lip Sync

It’s not surprising sometimes there are lip sync issues in live feeds, when you consider the amount of post processing that goes on in mixing the feeds from a remote location, bouncing around satellites from wireless links on location, etc

I do have a simple no cost solution though, it works for me when I get these issues on live feeds:

Look at the eyes of the person speaking, or the face of the person they are talking to. If you can train your brain not to look at the lips, you wont ‘see’ the lip sync issue.

I really dislike lip-sync issues - it just ruins TV viewing and when I had the issue, admittedly I became quite focused on it and just had to get it sorted.

I see some may choose go for the option of switching the TV audio format to the default PCM 2.0 stereo format, which is less demanding on the TV processor. Also some older TV’s apparently (in some instances) may do better when the optical port is used for the audio output instead, albeit that means using the Optical to HDMI Sonos adapter. I still think it’s worth considering an audio splitter, as I mentioned, I use the VAX04101A with our old (2015) LG Dining Room TV and a Beam (gen2) and that works really well to provide Atmos audio output from a Nvidia Shield - I haven’t seen a lip-sync issue since.

Our main TV is also LG, and newer (2019), and that has digital audio pass-through and when that’s set, it works well (perfect) too with the Sonos Arc. So I would definitely consider adding a splitter, even a cheap one will provide 5.1 Dolby Audio for less than £/€/$50.00 and worth that small outlay if you are otherwise happy with the current TV.

I’m confident I understand your technical points, I’m just disagreeing that the evidence must point to the TV only, specifically because it’s a Samsung. I provided the link to the HT receiver thread to show there is apparently more going on over HDMI than just two uni-directional media streams, not to demonstrate how the streams are routed. If that’s the case then it opens up some other options on where the problem could lie.

OP is able to reliably repeat an audio sync problem in the same way I can (by toggling the Dolby switch in the Q box), I’m assuming he’s seeing the same lag as me, which is why I’m interested in this thread. I have seen that another dolby source does not suffer from audio lag. From memory, I believe the QN85A I was using does have audio passthrough. I’m not disputing that Samsung TVs have introduced audio lag in the past but that doesn’t mean this issue has the same cause. 

I do not know if OP is using a TV with passthrough, optical or HDMI, a base, ray, beam, arc or amp. No-one really bothered to find out before mocking him. Hopefully he’ll come back and elaborate, but would fully understand if he didn’t.

OP seemed to think this needed to be a joint effort, not necessarily a Sonos only bug fix - a collaboration to resolve the problem wherever it might be. This steers me to thinking of handshakes too. I’m not sure if swapping Sonos with another brand sound bar will resolve though, the arcana suggestion would appear to have more chance of success for less cost albeit more Heath Robinson.

Short of taking over a different brand eARC TV and/or a different brand eARC audio device there’s not much hope of isolating the problem with my family member’s Q box. Sky devices are difficult to work with as the family IT support as they are pretty much locked to an address by Sky’s T&Cs and IP geo-location (apparently, but I don’t want to find out), Q box uses a special LNB,  Sky contract are prohibitively expensive to acquire as a test device (I’m not going to sign an 18 month contract just to test this out, they can live with stereo on Sky and surround on blu-rays for now...). In fact, over the years, h/w faults in sky equipment only seem to get resolved with major new products and now we have the standalone pucks this might be a non-issue. 

Absolutely agree, I’ve seen the same on Freesat, but that’s intermittent. What I’m seeing is 100% repeatable by switching dolby on/off on the Sky Q box regardless of the content playing so am discounting the satellite effect for this particular case. I don’t remember if I tested this on just live or recorded content too, or whether that’s even a relevant test. The bigger the TV the easier it is to ignore the lip-sync using your method :)

Switch to optical out instead. Even Samsung have a hard time adding a delay to that audio route.

I’ve re-read the OP who mentions Dolby Digital Plus. Thinking on it, it seems unlikely that a blu-ray would be sending a DD+ stream, more likely DD or TrueHD. Maybe the TV introduces a lag transcoding DD+ to whatever format goes down the ARC channel, but the other DD formats don’t follow the same process. Might go some way to explaining why the Q box behaves differently to other devices and gives me some other ideas to test.

Of course, I overlooked that it might not be CPU utilisation introducing delays. Samsung could have just dropped the incoming audio stream into a 1s long buffer for some reason, possibly internal lip-sync management but are just reading out way too late. I was assuming this would behave the same for all HDMI inputs, but I see now that Q box is using DD+ and the potential different behaviour.

This would limit Atmos and TV smart app usage though? I guess Sky users would be drawn to the apps on the Q box though out of convenience which apparently don’t support Atmos anyway

I doubt this sheds any extra light, but I’ve been testing with Sky Stream pucks for the last couple of weeks. It’s easy to create a similar delay to the Q by toggling the auto/passthrough settings on the LG TV. However, the lip-sync eventually corrects itself, possibly when new programme starts. The stream puck has options for passthrough/PCM stereo/dolby digital/dolby digital+/auto, so seems a little more advanced than the Q.

Conversely, I tried puck->Denon AVR->LG A1 and the sound was consistently synchronised, albeit manually set to a 75ms delay.

Audio sync issues are low on the list of problems I’ve seen with the pucks - erratic remote control behaviour has been hampering testing (I could try to get them replaced as it seems I’m not alone). From what I can find, there’s also a lack of surround (and UHD) content on the basic streaming offering to justify the effort of stabilising DD+ for non-sports/entertainment subscribers.

Atmos would not be possible, indeed, but if the audio is out of sync that’s not useful anyway. I don’t know how it would affect app usage though.

It’s a pain, arc/earc seem somewhat hit and miss with Sky, TV as hub and not only Sonos but other manufacturers too. Sony TVs seem better than most as the middle of the chain of devices with optical giving the most reliable but at the expense of most limited audio options.

This is true.  Fundamentally this is a TV problem.  For most of the time I have had Sonos HT (which is all the time Sonos has had HT products) I have bypassed the TV for audio in some way or other as a solution to this issue.  This has been necessary with Panasonic and LG TVs that I have owned.

Panasonic, LG and now Samsung (as reported on this thread) TV ARC/EARC implementations are all broken - despite the common component being a Sky device? (I don’t see this behaviour on any other device, albeit that they don’t emit DD+ either as I mentioned above).

I’ve now cancelled my Stream subscriptions but am keeping the devices to trial the service again in 12 months. They were immediately blocked by Sky, but I still see this other HDMI issue. Powering down the puck restores volume control of the Beam by the LG TV instantly. I seem to remember seeing other HDMI misbehaviour on Q and/or Sky+ devices resulting in users resorting to bending pins and buying CEC blocking dongles. There is something quirky about their HDMI implementation, but it used to be good enough for the majority of subscribers and only annoy people with Harmony remotes, AV receivers etc.  Now that soundbars seem to be more common I hope Sky will look into this (even if it’s something they need to resolve with the TV manufacturers rather than their own platform).