Video stuttering with UHD 60fps HDR10 content

Hi there,

thanks for your hard work, i like the new autoswitch functions. Currently i run into a small problem. I have downloaded some UHD HDR10 demos at 60fps, but they have video microstutter on playback, sound plays fine. 1st i thought, my HDMI cables are too slow, but this isn’t the case. Bought 2 new Oehlbach cables, but it doesn’t helped.

AVR: Denon X1300W
Apple TV 4K: Wired gigabit to NAS via NFS
If I played the files directly from USB - TV, they are fine. If i play them from USB through my Samsung UHD Bluray Player, they play fine, too. So the HDMI cables and AVR can’t be the problem.
If i play them as SDR (no content match and SDR desktop), they play fine in Infuse, too.

Perhaps someone can tell me, how to play the file through the build-in player, then i can say to 100%, that Infuse is the problem.

The File i play is this →

Mostly the fly-by shots microstutter, roofs and so on.

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Just out of curiosity, I clicked on your link, and the file began to play in Firefox.
I don’t know if dropbox was transcoding or something, because when I downloaded the 732 MB file locally to my Win7 PC, nothing would play it.
Not Firefox, Chrome, VLC 2.2.6, Windows Media Player … and not Infuse Pro 5.6.1856 on my iPad Air 2

I have no idea what my expectations should have been, but I did expect Infuse on the iPad would have rendered something

Thanks for the report.

We’ll take a look into what is going on here.

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FWIW I can see this too. Downloaded the file to my NAS share and played it through Infuse on an Apple TV 4k and clearly see the micro stuttering. Played through my Oppo UHD player the stutter is gone. I have an LG OLEDB6.

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Hi James, any news on this? Do you get the same results?

This video appears to be right at the threshold of what the current ATV4K hardware can handle.

For smooth playback of 60 FPS content, decoding should take less than 16.6ms (1/60) on average. What we are seeing here is that the decoding is a bit slower than that if Apple TV is in the HDR mode, presumably due to the extra load HDR puts on the system.

Here are the numbers for LG Colors of Journey:

  • 4K/60fps in HDR mode: ~16.5 ± 8.4ms (hence sporadic drop-offs)
  • 4K/60fps in SDR mode: ~12.6 ± 4.9ms (smooth playback)

This issue doesn’t seem to be specific to Infuse as it can be replicated in other apps, but there are a few things we may be able to try which could potentially help. Unfortunately these changes aren’t trivial, but we’ll see if we can find some time in the coming weeks to take a deeper look and see if there are any gains to be had.

Of course, it’s also possible Apple could implement some optimizations of their own in a future update for tvOS.


Such a powerful CPU can’t handle this? Hope Apple will improve this. Great answer anyway. :wink: TY

If you have billy lynn’s long halftime walk on itunes you should try that. That movie is in 4k/60hz/HDR on uhd disc. If its the same on itunes and that movie plays fine from itunes then apple tv can handle that and its a problem with infuse. If its not 4k/60hz on itunes then you are right.

This won’t apply to all 4k/60fps videos, just a few.

FWIW, videos from iTunes (60fps or otherwise) are highly compressed. An uncompressed UHD Blu-ray might have an average bitrate of 60-70 Mbps (with spikes up to 110+) but the same title from iTunes in 4K will average 25-30 Mbps.

There may be hope to improve things here, but it’s too early to say for sure. We do have the full Billy Lynn video sample here for testing though. :wink:

The limitation you are referring to in your previous post i thought it had to do with the fact that the video is 4k/60hz not taking into account the bitrate of the file. I have my eye on apple tv 4k as i want to use it combined with your app. If this is a problem due to apple tv hardware limitations is a no go. I have that video( lg colors of journey) and a lot of other 4k/59.94 or 60hz hdr videos and they play fine on the ipad 10.5 with infuse. But then maybe the screen is too small to notice micro stutters. Only if you have the billy lynn and you rip that uhd you will be able to determine the cause of this i think. Either the app on the hardware. Billy lynn from the uhd is around 90+ sometimes reaching 115mbits.

Well, it also plays smooth, if i force SDR and on iPad it will play as SDR too.

FYI, we’ve made a number of improvements in this area, and these 60fps HDR videos should all play perfectly in the upcoming 5.6.8 update.


With v5.6.8, 4k HDR 60fps movies are play very well without subtitles. However, when the subtitles are opened, there is a stuttering problem (Apple TV 4K, TVOS 11.3 beta 2)

Are there any particular titles you are seeing this with?

AFAIK, Billy Lynn is the only feature film that was shot at 60fps. Is that the one you are playing?

Personally I have tons of short 4K demo videos. The ones at 60fps usually play fine (with my huge surprise even one at 59.940 fps in VP9 format! Congrats!!). But there is one (which I see now is still in VP9, but at a round 60fps) that stutters badly (and even freezes few seconds). These are its details from MediaInfo:

General Unique ID : 33363864758205336206307750622331825678 (0x1919A588E094A99EA150CF4B3CF66E0E) Complete name : /Volumes/NAS326/4K-HDR Videos/LG SONY OLED 4K UHD SDR 60 FPS.mkv Format : Matroska Format version : Version 4 / Version 2 File size : 373 MiB Duration : 2 min 45 s Overall bit rate : 18.9 Mb/s Writing application : Lavf57.71.100 Writing library : Lavf57.71.100 ErrorDetectionType : Per level 1 Video ID : 1 Format : VP9 Codec ID : V_VP9 Duration : 2 min 45 s Width : 3 840 pixels Height : 2 160 pixels Display aspect ratio : 16:9 Frame rate mode : Constant Frame rate : 60.000 FPS Color space : YUV Language : English Default : Yes Forced : No Color range : Full Matrix coefficients : BT.709 Audio ID : 2 Format : AAC Format/Info : Advanced Audio Codec Format profile : LC Codec ID : A_AAC-2 Duration : 2 min 45 s Channel(s) : 2 channels Channel positions : Front: L R Sampling rate : 44.1 kHz Frame rate : 43.066 FPS (1024 SPF) Compression mode : Lossy Default : Yes Forced : No

I mean, I know that we are lucky enough to have VP9 at least partially supported, but I can upload the video in your Dropbox if you like.

PS: Any chance you guys can give to this forum a decent editor with menus for spoiler tags, formatting etc? :smiley:

Thanks for the info.

We still your other VP9 related todo open in our internal system but if you want to upload a second sample that would be great.

Yes, this is happening while playing “Billy Lynn…”.

I can also confirm stuttering with subtitles on and no stuttering with subtitles off. Tested with Planet Earth II.

Planet Earth II is not 60fps.

No, but it is 4K and HDR and stutters with subtitles on, but doesn’t with subtitles off. So there might be another issue specific to subtitles and high bitrate video.