There normally wouldn’t be any significant delay using toslink as that would cause lipsync issues, but wanting to hear sound from there AVR and the TV’s built in speakers at the same time is an odd request. Normally for these older setups you would just disable the TV speakers and use the AVR exclusively.
As for ARC you would need both a TV and AVR that supports ARC. If you have a newer AVR that supports ARC then the TV issue becomes moot as you would be better off plugging the Vero into the AVR and if you want to switch between TV and external speakers you just set the Vero input on the AVR as a passthrough device and the audio switching will happen automatically by turning the AVR on and off. If you had an ARC enabled setup and kept the Vero plugged into the TV it would also automatically switch the audio output device depending on if the AVR is on or off.
ARC is primarily designed for when the television itself is the video/audio source. So if, instead of using the Vero 4K+ to play audio and video, you threw it out and instead used an app that was built into a Smart TV, you would need some way of getting the audio out of your TV and into your AVR. That’s what ARC is most useful for.
I must confess I don’t entirely understand the problem here. If you have an AVR, why would you ever use the TV speakers? Why not turn the volume on the TV down to zero and leave it like that all the time, and just use the AVR for audio?
Alternatively, if you prefer, just stop using the AVR and always use the TV speakers.
But whichever you do, there is never a situation where having the TV speakers and the AVR speakers active at the same time makes sense.
If the issue is actually that the audio and the video are out of sync - in other words, the sound from the AVR is either ahead of or behind the picture - then that’s something you can easily correct in Kodi, you don’t need new equipment.
In addition to apps, ARC is also useful for people who have a 4K tv but an AVR that does not support 4K. In that case, you lose 4K video going hdmi 4K sources->AVR->tv. Instead, you would plug your 4K sources directly into your tv and use ARC to get the audio to your AVR.
ARC as such does not support HD audio formats. There is a more recent, whizzy version of it that does - eARC - but in order to use that, both your TV and your AVR have to be compatible with eARC.
If your AVR is recent enough to support eARC it will definitely also be recent enough to support 4K video input. If your AVR supports only plain ARC then you can’t feed it any type of audio signal via ARC that you cannot also send via optical S/PDIF.
So, if your AVR can’t handle 4K video, ARC won’t help you (or at least it will be no better than using optical). In that scenario you’re better off using an audio/video HDMI splitter.
Far less common 7.1 environments aside, why introduce an HDMI splitter (that you probably don’t already have) and lose HDMI-CEC functionality rather than ARC and an extra HDMI cable (probably already sitting in a drawer/desk/closet/etc)? Why use an optical cable (that you probably don’t already have) when you’d lose HDMI-CEC functionality, 2/3 the bandwidth, and no benefit from sending DTS instead of PCM? It wouldn’t make sense.
I, and a lot of people I know who are holding off on investing into a 4K+ AVR have opted for exactly the setup I described for exactly the reason I stated. For us this is an easy & suitable temporary solution that doesn’t need extra hardware, cost or compromise anything.
It is common to find AVR’s that support HD audio but not 4K and a splitter allows for the best possible quality without purchasing a new AVR. Slightly older AVR’s that have HDMI but not HD audio capabilities can receive multichannel PCM using the splitter approach allowing you to retain more of the audio quality vs. converting to AC3. Additionally a decent splitter will not remove the ability to use CEC.
There’s absolutely no reason to convert anything to AC3. And there’s no reason to waste money on a splitter when you can send PCM over ARC. Sending HD audio as decoded PCM is no different than sending bitstream that gets decoded to in the AVR instead. The only real advantage in using bitstream would be if you’re using wireless in your setup or have more than 6 speakers. Neither is the use-case of discussion.
If your AVR doesn’t support ARC then you would need to upgrade both the television and the AVR to use ARC. And if you’re upgrading the AVR, you’ll probably be upgrading to a model that supports 4K video pass-through, which makes ARC unnecessary.
As bmillham says, the most common (and best) configuration is Vero -> AVR -> TV. The only reason why you would use Vero -> TV -> AVR is if the AVR doesn’t support 4K video and the TV does.
Looking back I see that I misread what the OP said. For that matter, I wasn’t clear on some points either which didn’t help. Yesterday was one of “those days” here, I’m chalking it up.
@Yvan Your AVR power can be controlled by either HDMI-CEC (if supported) or your finger, take your pick. One of the setups here used to be such that HDMI went Kodi → Sony AVR → tv. The AVR was set to ‘standby on power-off’ and passthrough HDMI so the tv always got Kodi regardless of AVR on/off. If you wanted surround, you turned the AVR on. If not, turned it off. The tv was set to always use internal speakers so you always have sound regardless of AVR. It worked well for the needs in that area at the time.
To the OP: We have an audio setup guide in our wiki here…
You may find this useful for getting a greater understanding of how different setups work. The subject can sometimes be difficult for some as particular setups can have very specific things that need to be set to get optimal results and setups can be highly variable.
My couple of year old Yamaha can be set to passthrough when it’s turned off. But really why would you do this? It seems to me a be a hassle. You’d have to turn the TV speakers on/off manually. And you get far better sound with the AVR than the TV speakers could ever get you.
If you really insist on that type of setup, you could use the Toslink out of the Vero to the AVR. If you are having lipsync issues it’s adjustable in Kodi. Using the Toslink out of the TV may add additional delay that depending on the TV may be adjustable there, or again in Kodi.