Apple TV 4K


Newest Channels ATV Beta added auto switch to SDR

Works great.

I’ve now set ATV 4K (loaded with tvOS 11.2 beta) to 4K HDR.


How do i get the beta. I have 11.2 beta and hate having to turn off the hdr to watch live tv. ive been watching livetv through plex but thats a pain because the transcoding takes a lot of cpu power


I got it, thanks. didnt know there was a beta


How did you get the beta?


I had this problem until recently. Now everything is brighter even with the timeline showing. In fact, it’s almost too bright. Whites seem compressed and clipping. It could stand to be brought down a little. I wish there was some way to adjust brightness and contrast on the app. I have an Apple 4K and now Channels is brighter than any other app. Otherwise, it’s working beautifully.


@lcasta do you have your Apple TV 4K set to HDR mode?


Is there anyway to turn off the auto switching to SDR? I prefer the HDR for now but now I cant control it. Even if I turn off the setting in the appletv to switch, the channels app is still auto switching.


Weird, just tested that and I see that too. I thought it was handled by the OS, so I checked Netflix/iTunes and they didn’t switch but Channels still did. A restart didn’t change anything.

I like switching though for accurate colors and no added artifcats in the picture, so I’m going back to that.


I too was quite happy with Channels when in HDR mode - I found the “HDR Bright” mode on my LG to be fine, with the only issue being the weird flipping between dull/bright video when progress bar or quick guide overlays came up over video.

The annoying issue with video flipping suddenly between dull and bright for overlays was actually fixed in one of the early tvOS 11.2 Beta versions (think it was Beta 2) and that Apple fix ironically appeared a day or so before Channels was updated to cause a forced switch to SDR mode.

I too was surprised when Channels kept switching to SDR when I’d set the ATV’s Video settings to not auto-switch between HDR/SDR. Not sure if this is a flaw in Apple’s implementation of this new feature or an intentional override by Channels?

If the Channels switch to SDR is always going to be forced, I’d much prefer a setting within Channels to enable or disabled the forced switching. I understand the reasoning behind the switching, but it clashes with the preferences Apple have given now in 11.2, with which I prefer not to allow HDR switching due to being happy with the HDR and more annoyed by the delay the switching introduces as the HDMI re-negotiates on starting/exiting the app.


Interesting, I don’t recall this being fixed.

The method we’re using to force SDR at the moment is app-wide, added to our app’s manifest and enforced by tvOS whenever you switch into the app. This made sense to us since we know for certain that all broadcast content is SDR only.

If the HDR dimming issue is in-fact fixed, then maybe we can reconsider this. However making it optional is pretty tricky given the APIs currently available.


Yes, I think the overlay problem was fixed literally a day or so before the App Store release of whatever version of Channels implemented the SDR switch. I remember I saw it fixed, but then next time I went to check, Channels had been updated and it was doing the full SDR switch and I started to think it had been my imagination… however I noted that a couple other apps that used to suffer with the brightening on overlay were (and still are) fixed now even on the latest 11.2 Public Beta.

Shame the SDR switch isn’t more controllable. Sounds like this is more an ‘oversight’ or bug where Apple aren’t taking the Match Dynamic Range preference into account when the app manifest is used to specify the SDR?


If the dimming issue is fixed, we probably don’t need to force SDR any more. Will run some tests and try to get this sorted before 11.2 is released.


If I turn off depth changing Channels still forces a depth change to SDR if the ATV is in HDR mode. Presumably this is a bug on Apples part for apps using the manifest method.
What I do know is that SDR content using the system player now looks fine in HDR mode.
I might find an old TestFlight later today that doesn’t force switching and see how it looks.


I loaded up the oldest Testflight available to ensure it was a pre-HDR version. Apple seem to have fixed all the colour issues. The UI and video are bright and vivid in HDR mode and there is none of the dimming issues with the control overlays that we observed.
I’m still going to keep my aTV in SDR mode with depth and framerate switching turned on because my TV uses a bit more power in always on HDR.
For those that choose to keep their TV in HDR I think Channels should drop the manifest depth setting because the trade off in image quality is no longer a great enough incentive to tolerate the screen blank that accompanies a depth change on the aTV.
I do think Apple could do better with colour depth only changes though. I have the Sony UltraHD Blu-ray player and when this changes from SDR to HDR without a frame rate or resolution change there is no screen blanking at all on my Samsung and the internal TV apps such as Netflix/Amazon don’t blank either.


I completely disagree. Keeping it in HDR still causes small artifacts from the conversion, as well as the colors being a little “off” since it’s not a perfect conversion from Rec709 to Rec2020. I keep my TV in HDR, but that’s because Channels changes to SDR when you start it, and other apps I use change it to SDR when I’m playing a video that’s in SDR. The screensavers in HDR are great.


Okay we disagree. :smile:


Although my feelings aren’t strong enough either way to get heated about it for the developers.
I haven’t really checked out the screensavers because I rarely just let the TV waste electricity doing nothing. I did notice though that the screensavers don’t trigger an HDR switch because they don’t use the system player.
What can happen sometimes with my TV is that the HDMI subsystem crashes with resolution changes of the ATV and the TV has to be turned off and on again. It doesn’t occur with any other device. It is a very cheap Samsung Series 6 anyway which may be why I don’t get much of a “wow” with HDR anyway. At some point I’m going to go for an OLED but I’m going to have to give my wife a bit of time to get over the stuff I’ve bought this year!!!


It seems like when they added HDCP 2.2 for HDMI 2.0, everything has to be in sync so the switch can sometimes causes the HDCP handshake to error and all I get is similar to an old static channel. Older versions of the 11.2 beta seemed to be a lot worse, so the problem is mostly gone, but it still happens very occassionally.

I really think it’s an Apple issue, though. If Channels is still switching when the options in the ATV4K settings is turned off, then Apple should fix it before they push out the actual 11.2 update. Some people aren’t weird like me and don’t care or can’t tell that the colors are off, and might be happy leaving it in HDR.


Please test the latest beta and let us know how the HDR conversion is on the 11.2 GM


I’ve had to switch my ATV 4K to default SDR mode. The colours and black levels especially in Channels are still off with the automatic conversion if HDR mode is set as default.

I hope Apple resolves whatever bugs there are with HDR/SDR switching so you can re-enable forced SDR switching in Channels.