Does it work in TestFlight 12.31.208
Experimental drivers drop frames on multiple older TestFlight I have tried, including 12.31.208. Diagnostics from live PBS sent.
Okay then it seems to be a different issue. We isolated a regression after 12.31 which was just fixed.
Does v5.1.1 stable from the App Store work, or does that drop frames too?
yes, must be a different issue from the 12.31. Watching PBS now with the stable build. its 1920x1080 mpeg2 coming it at (99%,90%,100%) and at a relatively low bitrate, 5Mb/sec. And see frame drops with Experimental drivers, but not with Default.
I hope anyone who wanted to see it got the file I posted, especially @tmm1. If not, PM me.
On ATV 4K set to experimental there are frame drops throughout, but it is significant at about the 50 minute mark until the end of the show at around 52 minute mark.
There are no significant issues playing this file in VLC.
I am unable to recreate the issue with frame drops on this recording.
Are you able to see the frame drops happen when the stats overlay is not visible?
@eric, glad you got the file! I can't see the frame drops on my computer in VLC. But they are noticable on ATV 4k (v1) connected to a 4K Vizio TV, set at 4K SDR. And they happen with the stats visible too. Did you try it on ATV at around the 50 minute mark?
@eric, now that you mention it, I don't have the issue on my downstairs ATV 4K. So its either a setting or something wrong with the ATV. But they are both connected to 4K TVs. Set at 4K SDR YCbCr 4:4:4 with match Range & Frame Rate.
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I've watched from 48 minutes to 52 minutes with the stats off and on. In both situations I see 0 dropped frames reported.
I am using the same ATV 4k you are, but connected to a monitor that only does 60hz fixed refresh rate.
Originally I was testing using the Experimental Deinterlacer but I switched to the Linear one to match you and am also seeing 0 dropped frames.
This is very interesting that it's specific to a single setup...
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This is a shot in a dark, but you may want to try changing chroma 4:4:4 to 4:2:0. I was experiencing crazy dropped frames in the past with the experimental video driver and no one was able to recreate it, then I tried resetting my video settings and everything was fixed. I haven't had issues since and heavily suspect either a tvOS or Channels glitch in regards to the chroma setting.
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@eric, I think I got it fixed. Thank you, really, even though you didn't find anything specific, you pointed me in the right direction (it was some kind of configuration issue).
I don't know what happened, but I changed the output to RGB high, still had issues, the RGB low, no issues, then back to YCbCr 4:4:4 and did "Check HDMI Connection", which ran for a few minutes and reported no issues.
And now I can suddenly play back the video with 0 dropped frames on Experimental drivers. Crazy.
It is as if the ATV, or possibly the TV that it is connected to via HDMI, got in some kind of bad state and needed a refresh. I don't know.
Just to be sure it still works with the range and frame rate changing, I played a 4K HDR video on Amazon Prime, and watched the video change resolution. Then exited and played the Channels video again and started noticing the frame drops again with Experimental drivers.
Tried turning on "Match Content for Live TV", but still getting the frame drops.
Then switched ATV to 1080p SDR and then back to 4K SDR. Frame drops still there again.
Switched to RGB Low. No frame drops.
Back to YCbCr 4:4:4 with Match Content off. No frame drops.
Play 4k prime video again (at 4K SDR setting... not matching this time)
then back to Channels PBS video. No frame drops.
Manually set TV to 4K HDR and played Amazon HDR video. Then set back to 4K SDR and played the Channels PBS video. No frame drops.
Just to be sure, I tried turning Match Content back on and played the Amazon video again. And now it is still at 0 dropped frames. Did the same thing a few more times and then started seeing dropped frames again.
So I thought maybe this has something to do with the way the ATV Match Content works on this TV. But no, it increasingly appears more and more random.
YCbCr 4:2:0 seems to be currently working with no dropped frames, even with the Match Range and Frame Rate.
This is totally bizarre. But I thats all the testing I can do. There must be some change with the tvOS match that doesn't work right with the Experimental drivers.
The primary use of this TV is just a large TV monitor above my computer screens to watch OTA via Channels. Its working now using the 4:2:0. And looks great. Maybe it was overheating. I wonder if the 4:4:4 was pushing it too hard. This ATV is literally taped to the back of the monitor. I pointed a fan at it. Maybe that will help.
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@alai yes, you are right... i spent the last hour or so testing this and ended up with the same 4:2:0 that you suggested. It is working currently.
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On second thought, 4:2:0 helps, but thats not totally the solution. It still drops sometimes when switching between HDR on Amazon and then back to Channels. Something is not working right with the matching + Experimental drivers. But I do like the way the Experimental drivers work with the video interfaces better. It is smoother and works better with PiP.
So I am going to turn the match off on the ATV for now.
I also have match frame rate off, although I kept match range on. All of my other settings are default with 4K SDR 60fps. Channels has worked perfectly with this config and I experience only occasional frame rate jitters with other apps. Luckily I don't watch too many series in 25fps and everything generally looks good.
I'd love to have the confidence to turn match frame rate back on, but for now it's a happy compromise until Apple improves tvOS performance.
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Thank you! Turning off match frame rate worked for me for a little while, even on 4:4:4, but then eventually started dropping frames again. I'll keep it on 4:2:0 with frame rate match off. I wonder if this has to anything do with the specific TV being used, but I don't feel like testing it any more. There is definitely something not working with the way the ATV match works. But your settings are working great for me! Even switching between Netflix, Amazon, and Channels. Going to keep these setting for awhile. Will try the frame rate match again at a later time when I am actually watching something not in Channels.
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I think it's some bug/instability with the newer tvOS versions. I don't remember ever having these problems with early versions of tvOS 14 and I've had these issues with both generations of the Apple TV 4K, so I also doubt its hardware-related. Regardless, I'm glad it's working for you now!
I think the issue might be unique to the TV. But I have ATV 4k (v1) hooked up to a Samsung in one room and another ATV 4k (v1) hooked up to a Vizio in a different room. The Samsung works well on 4:4:4 with range and frame rate switching. The Vizio works best on 4:2:0 and can sometimes drop frames if frame rate switching is turned on.
I'm not saying its a problem with the TV. But it could be related to a tvOS update that caused the incompatibility. But its only on one of the two 4k TVs. Regardless, the default drivers work. Thats probably the most user friendly workaround right now.
Could also be an issue with the HDMI cable, to do 4:4:4 you need a lot of bandwidth and a high quality cable.
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Maybe. I had actually thought about that too, but just was lazy to get around to the back of the TV. I was using an ultra high speed HDMI rated for 8K video. Maybe its stopped working so well. Thats would be strange, but I have a few extra HDMI. I just found one that says "High Speed HDMI with Ethernet" on it. Trying that one now. So far so good. But the other one would seem to work for some periods too.... so need to test this different cable for awhile to be sure.
But this alternate cable is working great so far. On 4:4:4 with both range and frame rate matching. @tmm1, that was a good suggestion.
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Maybe just the cable wasn't the full solution. This seems to happen or YCbCr not all the time, but sometimes, after playing "The Grand Tour presents...", an HDR10 show on Amazon for a few minutes and then switch out of the app by pressing the home button. This causes the screen to turn black for a second and then back to ATV home screen. Then open Channels. And then some channels will drop frames, sometimes.
I then tried switching from YCbCr to RGB High, and Channels stopped dropping frames.
And then go back to play Grand Tour again. And switch back to Channels.... still not dropping frames.
Play some Dolby Vision Netflix, then HDR10 Amazon, then Channels. I have now done this full cycle of range + frame rate switching at least 4 times now on RGB High with the alternate cable.
And still no dropped frames. So I still think this might be specific to the TV along with the cable used.
So now I have found a setting that allows 4k full HDR + frame rate switching + no dropped frames in Channels. Will keep it on RGB high with the alternate cable. Hopefully this issue doesn't creep back again.
Btw, this is the short cable that was replaced:
