(I posted this in the Roku Player forum too, not sure which is proper)
First, my set up: New 2020 TCL Roku 6 series (R35). Older Onkyo TX-NR414 AV Receiver, connected via HDMI out to the eARC in on the TCL Apple TV 4k connected to HDMI 3 on the TCL (connecting it to the TV because the Onkyo doesn't support 4k)
Here's the issue: If I choose, under audio settings, "Auto Passthrough" for the s/pdif and eArc setting, I lose Dolby sound if I rewind or fast-forward a movie scene from any app on the TCL itself. For example, watching Inception (to test my surround sound) from Amazon Prime on the TCL.....I start the movie, my receiver shows the Dolby codec. If I rewind a scene, the receiver loses the codec and the surround is gone. I tested this with other native apps (Netflix, Disney+...same thing). So, to get it back I'd have to exit the movie and re-start it.
Now, if I watch the samemovie from the same app (Inception, from Amazon Prime) but this time from the Apple TV.....I do NOT lose Dolby when fast forwarding or rewinding.
So, that's issue #1, why am I losing Dolby if I rewind or fast-forward a movie or show from the TCL source.
Now, issue #2 is this: If I change the s/pdif and eArc setting to Auto Detect....my receiver shows the Dolby Digital Plus codec.....NO MATTER what the source.......for example, Casablanca is not DD+. The codec does NOT disappear when I rewind or fast forward, but it doesn't appear to be accurate. For example, using the same movie, Inception, it shows DD+ but it's really just DD.
I cannot for the life of me figure out what's going on here. (On an unrelated, or possibly related note, depending on which s/pdif setting and depending on if I'm using TCL or Apple, the lip sync in Amazon Prime video only can be quite off or dead on, and this seems to be only in Prime)
Just to eliminate the possibility, I did put new HDMI cables on all the connections.
A very similar thing is happening to me -- I just now joined to post about it. I also have a TCL 6, and mine is connected to a Sony STR-DH590 receiver. I have a 5.1 setup in our living room, and I like to use the receiver's Pro Logic II setting to upmix stereo signal (in shows/movies that don't encode 5.1) to play through my surround speakers. The only way I can get the PLII mode to work is to use either the TCL's Auto Passthrough or PCM-Stereo settings. I prefer passthrough so my receiver can decode DD+ signal when it's available. But same as you, whenever I rewind of fast-forward (in Netflix, Amazon, etc), my receiver loses the DD+ signal and instead shows that it's receiving Linear PCM. There's also a very noticable jump up in volume. If I restart the program, it goes back to DD+
I'd really like to find a solution that would allow me to use passthrough without having the TV lose the DD+ signal every time I rewind. For now, I'm just keeping it on PCM-Stereo and letting my receiver's PLII setting do its thing, but that's far from ideal.
I'm seeing the exact same issue on my TCL 6 series (625) connected to a Sony STR-DH790 receiver with Auto passthrough as the setting for audio in the Roku settings . Netflix, Amazon Prime, and Disney+ all start playback showing "Atmos - Dolby Digital Plus" on the receiver but as soon as I fast forward or rewind it converts back to Linear PCM. If you exit playback and then start it again it goes back to normal. Hopefully this can be fixed with a software update.
Same. If you fast forward or rewind on native Netflix and Amazon Prime apps on Roku TCL (9.4.0,Build 4206), it downgrades sound from DD+ (with or without atmos) to PCM 2.0. Have to exit the app and restart to starting DD+ back up, and in some cases reboot the TV.
From various threads, this has been confirmed in Series 5, 6, and 8 and model years 19 and 20. And it's been observed with Onkyo, Pioneer, and Denon equipment. It's definitely a bug. TCL or Roku need to patch this. We've spammed the Roku support account on twitter and got replies, but after then crickets. I've also been through the ringer with both TCL and Roku support and the best suggestion they can come up with is "turn it to stereo for everything" which is asinine.
@klambert wrote: the best suggestion they can come up with is "turn it to stereo for everything" which is asinine.
I've seen it mentioned before that these things start looking like bait/switch (false advertising). Not just random bugs, but a pattern of not caring about delivering features that sold the tv. The FTC involves itself in that. Your state AG does too (or, knows of a state agency that does. If you're in Canada, you probably have better protections).
In this case, for a TCL tv, even though I definitely understand the principle of the matter, it may be better to take the loss and move on. Post reviews to every retail site. File the complaints with government orgs. Plant a bug in the ear of class-action bottom feeders. A lot of this stuff looks like collusion tactics (TCL blames Roku; Roku blames TCL. Nobody's responsible. They're the winner that way. The customers of both orgs have one thing in common: losing.).
Figure you can sell the tv to someone without as much standards. Use the money to buy a Sony Android. (TCL makes Android tvs too. From one review I saw, those tvs will respond to a numeric remote. Like Roku, they don't come with one. But, if you spend $25 USD on a URC-7880 (for example), the Android version of TCL tvs will respond to the number keys, change channels, etc.).
If you read back through this forum. Roku never (I've seen) acknowledges a problem exists, or when to expect a fix (if any). People have been waiting years based upon "thanks, I passed it along." It's clear Roku doesn't care about its customers. One of the clearest examples I've seen is the so-called "cache clearing" (remote button sequence). That's really fixing problems for customers. But, last summer Roku mocked its customers to a news outlet, saying there is no cache (implying this solution is a myth). Eight months ago. Instead of explaining what it does, or why it's fixing problems, or what Roku would do to eliminate the root cause of customers having to use it, all they had to say to the news outlet was "there is no cache (eye roll) silly customers" (loose quotes).
We see that disregard for integrity over and over. Just sell it to someone who doesn't need dolby, etc., buy a different tv. Even a cheap TCL Android. That would give you some time to see if it delivers the advertised features (within the return window). Spend $50 USD on the 4-5 year extended warranty. I don't usually buy those. But, in the case of TCL (the lack of clarity about who's causing these problems), I'd do it. Definitely TCL Roku. Just not sure if Android on TCL is as problematic.
"People are often amazed at how much we’ve done with the number of engineers we’ve got." (Roku CEO Anthony Wood, Austin Statesman, Oct 4, 2019). "Amazed" is one way of putting it.