I’m on the April release and have come across one title so far (Despicable Me) where a chapter skip event crashed the picture playback but sound continued. It’s somewhat reproducable but I have not looked into it in detail yet. As I don’t play much UHD content I’m not sure if this is a new failure since the April release or not. It reminds me of the behaviour during March when dynamic buffering settings were being tweaked in the test build and occasionally I had to revert when chapter skipping got broken. If I find the time I will look into this some more. I use a gigabit adapter and NFS mounting via Kodi. Buffer recovery after chapter skipping is normally excellent with this configuration.
Here is an example of crashed picture playback. I did a great deal of chapter skipping and scrubbing over the three Despicable Me films and everything was perfect for so long I thought I’d imagined the problem yesterday. The gigabit adapter provides superb scrubbing performance. And then when I was about to give up, this happened - the image freezes with some display corruption, but the audio is fine (I left it for a good 10mins after this and sound just carried on). On stop/resume, all was fine. This is a little tricky to reproduce for a log as I think it may only happen when scrubbing, and most of the time, there’s no problem.
We would advise to use NFS mounting via fstab, first as a test, but also as a better experience overall with high bitrate content.
With the gigabit adapter I find there are almost no issues with NFS via Kodi, even on demanding chapter skips. I really tortured the Vero today to get it to break on scrubbing via the iOS remote. When I had a chapter-skip issue before getting the adapter, fstab fixed it, but it broke my network remote control from my iPad as the Vero seemed to choke on the throughput. The gigabit adapter side-stepped that problem and also delivered even faster scrubbing performance than fstab over the built-in wired connection. I guess that Kodi mounting might still be a factor in my now rare cases of a scrubbing glitch.
I’m also keen to see how the Vero does without resort to back-end fiddling with share mounting. Seems like it’s almost there. Thanks to all involved.
Retested all my problematic movies regarding buffering in the June 2018 update. All previous sudden drop in buffer are now gone! Buffer now is steady around 187MB with only minor drifting with extreme bitrates. So something good happened here (I have not done any change to my local network or NAS devices with movies).
So this is fantastic 
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After many months of trouble-free playback of scores of 4K/HDR/Atmos remuxes on my trusty Vero 4K (not +), I finally found a file that tripped it up, namely a 1:1 remux of 2013’s Pacific Rim.
I have always used an fstab-based NFS mount to my GbE NAS (albeit via the Vero’s 100MbE NIC).
I get sustained bi-directional iperf results between the Vero and the NAS of 95Mbps and have never had any issues up until now.
However, on this file, from around 1hr 13mins onwards I had multiple occasions where the framerate started slowing, sound went out of sync and eventually turned into a slideshow if left to its own devices. Pausing, waiting a few moments and resuming fixed it and restored smooth expected playback until the next time it happened. From this point on until the end of the film I would say it did this 5 times or so.
Is this movie considered “problematic” as JW2, Serenity and a handful of others have been noted?
From a debug log, there were a few notable event types repeated:
CRenderManager::PrepareNextRender m_QueueSkip:x etc.
ActiveAE::SyncStream - average error xxx above threshold etc.
plus sometimes:
Readrate xxx is *too low* with xxx required
I have tried doubling the stock “memorysize” value to 1049760000 in advancedsettings.xml which I think helped get rid of the “Readrate too low” messages, but I was still observing sporadic framedrops and stutters when testing in a limited fashion last night.
Could increasing the /sys/module/amvdec_h265/parameters/dynamic_buf_num_margin up from the stock “12” help here - I don’t really know what the side effect of this would be elsewhere so would rather leave alone unless it proves beneficial?
Has anyone else experienced issues with this particular remux?
Did you try playing it locally to discount it being a problem with the file itself?
That would have been my very next test, but it was very late last night by the time I was done fiddling. I’ll try again when I get a moment - was just interested initially if anyone else had the same issue with the same media…
I had no problem with that file on my old Vero4k but I was using a USB3.0>Gigabit adapter.
I’d recommended one for less than tenner and you will triple your connection speeds to ~330mbps
Currently I’m using USB3.0>Gigabit adapter on my Vero4k+ (as I’m suffering from issues in its network port) and again the file plays back no problems.
Don’t know if this helps you.
You could try upping this to 16. It’s not persistent so you can reboot if you experience an issue.
I haven’t heard of issues with this film; but there may indeed be problems with it.
Sam
A quick test of dynamic_buf_num_margin at 16 rendered it unwatchable.
One of the problem sections (which can be triggered every time by skipping from anywhere in chapter 8 to 9) showed artifacts all over the screen, random mosaics and large blocks of colour etc.
I tried each integer from 16 back down to the default of 12 and each showed problems like this that admittedly lessened as the number was decreased.
With the double-amount value in “memorysize”, the playback actually “recovers” by itself with audio gradually coming back into sync and frames speeding back up to the expected cadence after stuttering. It takes probably 15 seconds or so to settle down. Before, the image would eventually freeze, audio would stop yet Kodi still thought the file was playing.
It’s certainly better, but far from perfect. Perhaps by skipping immediately within chapters around a very high peak bitrate scene it may cause an unrealistic change that cannot be buffered fast enough with a 100MbE connection.
Strange that I’ve watched many 4K remuxes over the last few months and none have had any problem whatsoever - I can skip chapters or step through in multiple minute increments in every other file I’ve tried freely with no stuttering.
@SLICKRIC21: thanks for the tip - I had been considering this despite my previous excellent experience and comments from others on here that 100MbE is more than enough for smooth playback of 4K retail remuxes. I already have one of these adapters lying around so I will give this a try and also local playback from a USB 3.0 external HDD later.
Whilst I was waiting for the file to copy to my USB HDD, I tried out a USB 2.0 to GbE adapter which is all I had lying around.
It was plug/play and configuring it via MyOSMC was plain sailing. I now see iperf results of 318Mbps between the Vero 4K and NAS.
I do not see ANY artifacts, stuttering, incorrect frame-rate cadence, audio drop-outs or the like when skipping about during problem segments.
I think we can safely assume that it must definitely be bitrate/buffer/cache/network related due to the 100MbE on the Vero 4K. I think I’ll be leaving the GbE adapter connected permanently now.
I’d be interested to know how to analyse the bitrate over time of any given file to see peaks/troughs and maybe to spot problem media in the future - does anyone know a way (that preferably runs under Linux)?
Press the key that looks like:
~
~
~
and then OK and you can see video bitrate
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Glad you sorted it !!!
Just for information… Interstellar is unplayable for some seconds after 02:19:51… the picture freeze and the Vero is buffering! Test it with fstab NFS, GB LAN adapter and and the “echo 12 | sudo tee /sys/module/amvdec_h265/parameters/dynamic_buf_num_margin” option (don´t know if this is needed after the April 19 update)! Think the bitrate is too high for the environment…
You are replying to a 7 month old topic. I doubt that your problem is related, but you mention trying different network sources; have you tried with the file local on the Vero (like on a USB stick) to rule out network issues?
No, haven´t such a usb stick yet, movie has 70gb! Post is just for information, this is the first movie with stuttering for over a year, i see many other movies with highest bitrate like John Wick 2, Terminator 2, Serenity, etc. without any problems after changing the Vero network connection to the USB GB adapter!