4k + h264 + 24fps = lots of "skipped" frames

I’m moving from an Odroid-C2 because the Vero4K offers much support for HDR10. I was shocked to see that all my 4K videos at 24fps (really 23.976) are skipping at a rate that is very distracting. When I press ctrl-shift-o, I observe the “skip” value ticking up, and each time it does I notice a quick stutter on the screen.

I play the same exact files on my Odriod-C2 (running LibreElec) through the same HDMI input of the AVR, and no such problem occurs.

The only work-around that fixes the problem is to disable “Adjust display refresh rate” which of course drops back down to 1080p. So that’s not really a solution. The option “sync playback to display” makes no difference in the problem. Audio pass-through makes no difference either; I’ve tried both ways several times.

I started by testing the firmware that came on the Vero4K (January 2018), and thought maybe an update (to April 2018) would fix it. No change in the skipping was observed though.

I am playing from a USB-attached SSD drive to ensure no network issues are getting in the way. The problem seems uncorrelated to bit-rate; a 5mbps can skip badly but a 60mbps video at 25fps plays just fine! Hard to understand eh?

In reading this forum a bit, it seems this “skip” statistic is related to clocking differences between audio and video- could it simply be I got a bad unit? Should I just exchange it for another one and this problem will go away? If any of users could confirm your 4k@24fps videos play fine that would really help know I just got a lemon.

AVR: Denon X1400H
Projector: Epson 6040UB

I removed your reference to the sample as this violates the piracy policy of this forum.
If you want to share a sample either cut a short piece of the movie and share it or use a legally available video as an example

H264 and 4K is an odd combination, normally 4K would be encoded with H265. I’d think that a 4K with H264 has been recoded from H265 so has lost quality and is not truly 4K any more.

What’s the mediainfo on one of the files in question?

It would be good if we could find out more about the file you are having issues playing. Please see the mediainfo section in How to submit a useful support request - General - OSMC

If you can play 60mbps 4K content you likely haven’t got a defective device. If you had faulty you would see other, serious symptoms.

If you can play the file with 1080p output but only experience issues with 4K, then it’s also not indicative of a hardware problem.

A debug log and MediaInfo of the file you played, with a small sample if possible will help us resolve this for you promptly

OP may be playing anime which is Hi10.
There are improvements for this in Kodi v18 but it must still be played back in software.

It’s unclear what version or build of LE was used by op on C2, but I’m sure we will get more details soon.

Thanks for the howto on mediainfo- here’s the output:

http://paste.osmc.io/obonutivak.tex

I think they encode to h264 since HW acceleration is still pretty scarce on h265 still. Phones and tablets for example are still purely h264 in the ASIC as I understand. No one wants a dead battery half-way into a flight!

Can you play it and post a debug log? I think I know what the issue may be

Hi Sam- thanks for the reply. I’d like to help get this working so we can all have one box to rule the world.

I’ve used several versions of LE, mostly “7.1.0-Aug” (a wrxtasy build for the C2). That’s a Kodi 16.1 Jarvis based version, but I’ve also experimented with version 8 (Kodi Krypton) and didn’t notice any skipping. I would have picked up on that very quickly.

I am confused why h264 is surprising- I even still render my UHD home movies in h264 because there still isn’t wide HW support for h265. My h264 renders play perfectly on the Vero4k because I use 29.97 fps. It seems the safest bet for some time. I can’t even play h265 on my PC very well without stuttering!

I will get a debug log together for you and reply with it.

Did you play this same file on the C2 then?
Really without a debug log we are just speculating

You can play HEVC without issues on a Vero 4K. Most 4K content is encoded as HEVC now.

Thanks

Sam

Seems odd to me to take UHD and lose quality by re-encoding it instead of just re-muxing it so you get true UHD quality. But I guess if you need to play it on non H265 capable hardware you don’t have much choice.

Ok, debug log is ready for inspection:
https://paste.osmc.tv/sisodujebu

This was generated while playing a file called “Kong.Skull.Island.2017.4K.UltraHD.BluRay.2160p.x264.TrueHD.7.1.Atmos-POOP.mkv” from a USB-attached SSD drive. There were many skips in just the first few seconds.

Here’s the mediainfo for that file:
http://paste.osmc.tv/jojozevoxu.tex

Hope it points out the fix!