New ATV4K owner w/weird glitch

JMEANS

macrumors regular
Original poster
Jun 9, 2012
150
2
Apple TV user since ATV2 and just upgraded to 4K 64g puck. Love all the new features, interface options, remote etc. I watch backed up files majority of the time via Ethernet hookup and in doing so clearly noticed an upgrade in clarity and sound! Holy cow was there an improvement over the ATV3! That being said, can anyone tell me why files over 10gig fully loaded on screen is glitching? It will play for awhile, fully be loaded then for whatever start freezing while audio is fine?! Weird issue I never had with the ATV3 (same file & setup) Espesvially when this puck clearly has more power etc. Is there a setting I need be made aware of? Thx for any help you can offer. Frustrating.
 
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I have this problem too with the same wired setup. I've also hung onto the "4" and the very same movies play fine. So there seems to be bug in the 4K that doesn't affect the 4 (before the defenders try to spin 4X more pixels, the 4K will show this problem on a 1080p TV too).

I thought I might have figured it out as a bug with the frame rate matching feature. I turned that off and a movie that regularly showed this stuttering did not stutter. However, later playing that same movie with frame rate match off DID show that stutter again.

I've also considered TV settings maybe being at fault, but I sub in the old "4" box with all else being the same and the movies have no problem. So I'm resigned to believe there's some bug in 4K playback with home media that will play fine on the 4. I know this will lead to several claiming their's play back everything they throw at it perfectly, to which I'll say good for you, but that doesn't help us with the problem.

For now, I just go back to the 4 when I want dependable playback.

2 other issues with my 4K vs. the 4:
  • Quick scroll (of a long list) works fine on the 4 but starts & stops & starts & stops on the 4K. My best guess is that this is a list buffer issue and- IMO- seems like something that could be remedied by storing the whole list on the :apple:TV instead of freshly loading it each time. If list plus thumbnails requires too much space, store the list but not the thumbnails and fast scroll separate from the process that is trying to populate thumbnail placeholders.
  • The 4K seems to have some trouble waking a sleeping Mac (or maybe just losing the connection to the home library in iTunes). The "4" doesn't seem to do this. Remedy for this is usually unplug, wait, plug the 4K back in.
Historically, Apple usually gets around to squashing such bugs but it can be a long, long wait.
 

JMEANS

macrumors regular
Original poster
Jun 9, 2012
150
2
Thanks for the reply, at least I know I’m not alone with the issue, and yes hoping a fix comes sooner than later. Jim
 
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lessismo

macrumors newbie
Aug 15, 2011
27
0
Paris
I got similar issue here.

I use iTunes to stream my BD backups, H264 1080p, only remuxed with Subler. ATV4K computer app playback is laggy, sound keeps being fluid with video getting slower and de-synchronised (by up to 5s in worst case), then video fastforwards to synchronise with sound again. ATV4 was 100% fluid.

It is clearly a question of bitrate/file size, the bigger the worse.
I guess this is actually a buffer management issue. I could strongly reduce the problem by reducing the ATV4K ethernet connection to my router from 1Gbps to 100Mbps :).

I have done multiple things trying to solve that issue, so it would be great one of you to replicate this (non-perfect) trick to validate it. Thx !!
 
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benji888

macrumors 68000
Sep 27, 2006
1,788
362
United States
Apple TV user since ATV2 and just upgraded to 4K 64g puck. Love all the new features, interface options, remote etc. I watch backed up files majority of the time via Ethernet hookup and in doing so clearly noticed an upgrade in clarity and sound! Holy cow was there an improvement over the ATV3! That being said, can anyone tell me why files over 10gig fully loaded on screen is glitching? It will play for awhile, fully be loaded then for whatever start freezing while audio is fine?! Weird issue I never had with the ATV3 (same file & setup) Espesvially when this puck clearly has more power etc. Is there a setting I need be made aware of? Thx for any help you can offer. Frustrating.
Has the tvOS 11.4 update fixed this? If not, report this as a bug to apple (use "report a problem"): https://www.apple.com/feedback/appletv.html This is quick and easy to do, and, they do read these and sometimes you will see something fixed. ...Alternatively, if you're still under warranty or AppleCare, contact them through support also.
 

priitv8

macrumors 68040
Jan 13, 2011
3,655
486
Estonia
In my experience aTV 4K won’t play streams over 50Mbps in bandwidth smoothly. In UHD resolution I mean.
If you try to send direct BD rips without downconverting the bitrate, you will see the picture stutter.
 

lessismo

macrumors newbie
Aug 15, 2011
27
0
Paris
In my experience aTV 4K won’t play streams over 50Mbps in bandwidth smoothly. In UHD resolution I mean. (...).
Thanks for sharing. Same approx. 50Mbps limit here, whatever HD or UHD, using iTunes/Computer app.
(It is actually worse with ATV4K than ATV4, I think for buffer reasons).

Do you know if Infuse faces same limits ?
Thx !
[doublepost=1527945869][/doublepost]
Has the tvOS 11.4 update fixed this?
No 11.4 does not change anything unfortunately.

If not, report this as a bug to apple (use "report a problem"): https://www.apple.com/feedback/appletv.html This is quick and easy to do, and, they do read these and sometimes you will see something fixed. ...Alternatively, if you're still under warranty or AppleCare, contact them through support also.
Mmm I have not found max bit rate in spec, but iTunes/Computer app are primely focusing on Apple Movies which are not reaching files over 10gig. Low priority pb.
 
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priitv8

macrumors 68040
Jan 13, 2011
3,655
486
Estonia
Do you know if Infuse faces same limits ?
Thx !
It has less problems, meaning it plays back my 67Mbps test clip. It also struggles with 139Mbp AVC clip.
Part of the difference in behaviour may also come from the communication protocol - Computers app uses Home Sharing, Infuse direct file access to network drive.
 

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lessismo

macrumors newbie
Aug 15, 2011
27
0
Paris
Thank you much priitv8, I tested Infuse yesterday after your answer - it seems a good alternative for now.
 

loekf

macrumors 6502a
Mar 23, 2015
679
273
Nijmegen, The Netherlands
Thanks for the reply, at least I know I’m not alone with the issue, and yes hoping a fix comes sooner than later. Jim
It's not just playing stuff via Home sharing from a Mac.

When I play files via MrMMc from a NAS, pause, and let the 4KTV go the sleep sometimes it wakes up w/o a HDMI connection (= just blue screen).

Leaving it go to sleep in the home screen is always ok.

My theory is that it has something to do with re-establishing a network connection to my NAS.

It's not the 4K, the non 4K has it as well.
[doublepost=1528125817][/doublepost]
It has less problems, meaning it plays back my 67Mbps test clip. It also struggles with 139Mbp AVC clip.
Part of the difference in behaviour may also come from the communication protocol - Computers app uses Home Sharing, Infuse direct file access to network drive.
Correct. With MrMMC we tested the HW HEVC decoder framework of tvOS. Testing all kinds of known test streams with pretty high bitrates were no issue for the ATV 4K. The 4K has more or less the same capabilities as a HW decoder you find in a modern PC graphics card.

Still it's interesting that playing 4K files via iTunes/Homesharing has limits. I'm not familiar with the protocol iTunes is using, maybe the limit is more on the Mac side. Perhaps, there's transcoding involved (like Plex).
 

priitv8

macrumors 68040
Jan 13, 2011
3,655
486
Estonia
Perhaps, there's transcoding involved (like Plex).
That is highly unrealistic!
My 2012 i7 CPU is unable to re-encode UHD HEVC stream into much anything in real time. Yet, the iTunes AirPlay/Home Sharing works for streams below 50Mbps. UHD needs also to stay under 30fps. So no 2160p@60fps playback.
PS that said i7 has hardware AVC encoder onboard, it's too old to have HEVC encoder.
 
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