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Stuttering on 4K Content with audio encoding

stuttering 4k encoding transcoding

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#21 nanuk OFFLINE  

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Posted 20 August 2018 - 09:44 AM

Hi Luke,

I think I finally found out what causes the stuttering when watching a 4K movie with TrueHD Audio transcoded to AC3.

 

The harddisk with the transcoding directory seems to be the bottleneck.

An incredible amount of files (all about 20mb) are written in the emby transcoding folder, all of the contain about 7 sec. of the movie (picture an sound).

So that the HDD is reading and writing with more than 120mb/s. And thats too much :-/

 

Is this a normal behavior? 



#22 Luke OFFLINE  

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Posted 20 August 2018 - 11:29 AM

That's the transcoding format that we use, yes.

#23 VellaiT OFFLINE  

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Posted 23 December 2018 - 09:38 AM

Hi - Checking if there has been any progress from LG on this as I have the same OLED and issue and unfortunately I just cannot get the same quality picture running HDMI directly from media server to TV... so I am using the LG emby app as the colours are superior... If I play directly from my media server to TV the image looks lifeless and colours washed out.

 

Quite sure my hardware is up to the task - Gigabyte H370N with HDMI 2.0, i7-8700T with Intel 630 HD graphics, 16Gb  DDR4 Memory, 8x Server 7200 SATA drives with 4x 800Gb SSD cache on Windows 10 with storage spaces + NVME OS drive running emby and all equipment running on Cat6 gigabit lan from Meraki enterprise switch....no wifi.



#24 Luke OFFLINE  

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Posted 23 December 2018 - 07:03 PM

Hi, are you having any problems with the app?

#25 VellaiT OFFLINE  

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Posted 23 December 2018 - 10:58 PM

With 4K Remux MPEG-H HEVC 2160p 10bit HDR10 / True HD/Atmos 7.1 24bit, it will pause/stutter on playback every few minutes and the only way I have found to smooth it out is turn subs off completely, switch to 5.1 dolby digital audio track then back to the True HD track then it seems to play for 30 minutes or so before happening again.

 

CPU/Mem/DIsk for media server at these points are hardly being touched so its not Disc I/O or CPU maxing out.

 

When I playback in browser with emby over HDMI to TV the colour is washed out. Same with Kodi.... so would be really like to get the LG app sorted.



#26 nanuk OFFLINE  

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Posted 24 December 2018 - 02:15 AM

With 4K Remux MPEG-H HEVC 2160p 10bit HDR10 / True HD/Atmos 7.1 24bit, it will pause/stutter on playback every few minutes and the only way I have found to smooth it out is turn subs off completely, switch to 5.1 dolby digital audio track then back to the True HD track then it seems to play for 30 minutes or so before happening again.

 

CPU/Mem/DIsk for media server at these points are hardly being touched so its not Disc I/O or CPU maxing out.

 

When I playback in browser with emby over HDMI to TV the colour is washed out. Same with Kodi.... so would be really like to get the LG app sorted.

 

Hi VellaiT,

I have the exact same problem and the reasons are now clear and the emby app is NOT responsible for the problem :-/

 

When I play a 4K Remux MPEG-H HEVC 2160p 10bit HDR10 / True HD/Atmos file (and True HD/Atmos is really the only format the playback is stuttering) I looked on the device manager of my Windows Server and determined that the HDD that emby uses to transcode is at 100% after a few minutes/seconds and that's exactly when the playback begins to stutter!

 

Even when I use a SSD to put my temporary transcoding path on, the problerm still exists... BUT the stuttering gets better... that's an indicator that the reason really is the speed of the HDD. because the system is writing to the harddsik with full speed and is trying the read from the same disc at the same time... I think if there woukd be a possibility to prioritize the read and write tasks of the system, that would solve the prob, but actually I found no way to do this.

 

True HD/Atmos is the only audio format that has to by transcoded by emby because the LG TV seems not to be able to play that naturally. 

 

 

->When I playback in browser with emby over HDMI to TV the colour is washed out. Same with Kodi.... 

 

The reason for this is that your playback device you are running kodi on is not able to send the HDR information to your TV, maybe the graphics card is not HDMI 2.0 compatible or samething like that.

Kodi 17.x is not able to do a HDR to SDR conversion so that the colours are looking terrible and as you described "washed out".

 

The upcoming Kodi 18 is able to do a HDR to SDR conversion maybe you can try this one ;-) there is already a RC3 out and I think the final version will be there in a view days.


Edited by nanuk, 24 December 2018 - 02:18 AM.


#27 VellaiT OFFLINE  

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Posted 24 December 2018 - 02:30 AM

Hi,

 

Thanks for taking the time to respond.

 

The first thing I was thinking was CPU or Disk I/O aswell, but I have watched this carefully and emby doesn't use even 20% of the bandwidth for disk even when the pause/stutter happens.

 

I have dual 800Gb Intel DC S3520 cache on both read and write to 7200rpm 8 drive WD Gold array. This system can easily serve 10+ simultaneous users editing 4k raw video files...so it should be able to handle 1x 4k compressed stream.

 

I had a feeling it was a HDR issue with the colours on HDMI direct output, I have confirmed the board definitely supports HDMI 2.0 so will have to work on driver tweaks until I get it working correctly.... I will also check out Kodi beta again as well... its been a while as I made the switch to emby premiere around 6 months ago and have been working through some network upgrades and server upgrade etc.

 

In regards to the audio - I understand the LG cannot decode the True HD natively from other posts, but I am passing through to a NAD M17 V2 Processor with ARC and not using the LG... do you think this would still present the same issue? Seems odd that if I switch stream after movie starts then back again, the audio is fine from then on. 



#28 nanuk OFFLINE  

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Posted 24 December 2018 - 02:52 AM

I have dual 800Gb Intel DC S3520 cache on both read and write to 7200rpm 8 drive WD Gold array. This system can easily serve 10+ simultaneous users editing 4k raw video files...so it should be able to handle 1x 4k compressed stream.

 

 

Of course it should be able to handle 1x 4k compressed stream... the problem is that emby writes to the disc with full speed, that means in case of a 4K movie (50-70GB) it is not transcoding in real time but it transcodes / writes much faster to your HDD than it reads.

to show you I startet a 4K movie with TruaHD  on my LG TV and made a screenshot of my hardware manager after about 3 minutes, when the stuttering started for the first time.

At this time emby/ffmpeg is writing with 140 MB/s to the harddisk and is trying to read at the same time... and thats not working well :-)

 

This also explains why the 4K movies are only stuttering when you use the Atmos/TrueHD audio and all others (DD5.1/DTS MA/DTS:X...) are working well and without stuttering!

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#29 Luke OFFLINE  

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Posted 24 December 2018 - 02:52 AM

So the TV is outputting to the receiver via HDMI, is that correct?

#30 nanuk OFFLINE  

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Posted 24 December 2018 - 03:00 AM

So the TV is outputting to the receiver via HDMI, is that correct?

 

In my case yes...



#31 nanuk OFFLINE  

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Posted 24 December 2018 - 03:12 AM

The first thing I was thinking was CPU or Disk I/O aswell, but I have watched this carefully and emby doesn't use even 20% of the bandwidth for disk even when the pause/stutter happens.

 

 

a good way to test if it's really not your HDD is to just let the movie play for lets say 10 minutes (ignore the stuttering) and I bet after about 10 minutes (depending on the transcoding speed of your system) after the transcoding is completly done the playback will run smooth ;-)

and do not rewind or fastforward because this will force emby to do an new transcoding process ;-/


Edited by nanuk, 24 December 2018 - 03:13 AM.


#32 VellaiT OFFLINE  

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Posted 24 December 2018 - 03:25 AM

Hi Luke - yes its HDMI ARC back to the processor.

 

Nanuk - I will do some more testing, but if this is really the issue then emby need to address it, this is top tier hardware short of going full NVME storage which is unrealistic for 99% of home users.

 

I was having this same issue previously with a synology DS1817+, but that was CPU maxing out as its a quad core atom so not surprising... It wasn't showing disk I/O anywhere near max either as I have dual SSD cache on that also that far exceed the size of the file being processed.

 

Might have to keep on going with HDMI 2.0 issue and if I get that resolved look at switching back to Kodi.



#33 nanuk OFFLINE  

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Posted 24 December 2018 - 03:29 AM

Nanuk - I will do some more testing, but if this is really the issue then emby need to address it, this is top tier hardware short of going full NVME storage which is unrealistic for 99% of home users.

 

 

Yes, I totally agree... and please do the testing and let me know about your result... this problem bores me for months :-/



#34 VellaiT OFFLINE  

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Posted 25 December 2018 - 05:39 AM

So I have spent the day on it today....really makes no sense to me...

 

CPU hitting 84% max and disk hardly being touched. Constant stalling and stuttering on playback to a point where I am going to another source as its unwatchable.

 

I have tried intel hardware acceleration on, off, prioritise emby and ffmpeg to high and real-time... no other services running that can use major resources.

 

No amount of pause and wait for it catch up works either, letting it run for 15-20mins makes no difference. Really starting to Pi$$ me off.

 

Screenshots from 3 different points, but it's all pretty much the same.

 

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Edited by VellaiT, 25 December 2018 - 05:43 AM.


#35 Luke OFFLINE  

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Posted 25 December 2018 - 01:17 PM

Hi, try using the quality setting in the video player to lower the quality to a value that your network can  handle. Thanks.



#36 nanuk OFFLINE  

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Posted 25 December 2018 - 03:48 PM

@VellaiT

what Luke said is another very interessting point...

All LG TVs only have 100mbit networkinterfaces build in :-/ 

that's in case of a 4K remux sometimes a bottleneck :-)

 

sad but true... I use a wireless network connection because it's faster :-))) 



#37 VellaiT OFFLINE  

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Posted 25 December 2018 - 07:55 PM

Hi Guys,

 

Yes I had read that before somewhere else and already have it set to 4k 100mb.... no difference in performance.

 

I will try the wifi like you suggest aswell and see if that has any bearing on this...



#38 VellaiT OFFLINE  

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Posted 26 December 2018 - 02:52 AM

No such luck with the wifi either, tried 4k/80, 4k/100, 4k/120 and just as bad with all of them on wifi or ethernet.

 

The server is barely being touched CPU/Mem/Storage/GPU so looking like this is just not going to work.

 

Back to Kodi and getting HDMI 2.0/HDR sorted.

 

Let me know how you go when Server 3.6 out and ill retest then... failing that its time to cancel the premiere subscription and get a refund.

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#39 Luke OFFLINE  

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Posted 27 December 2018 - 03:34 PM

I would try lowering the quality setting even further.



#40 VellaiT OFFLINE  

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Posted 28 December 2018 - 08:35 AM

Yeah na.... that's not a solution... to get it to play smoothly its back to 1080p which defeats the entire purpoise of having this kind of kit and source material. I have kodi running properly now and HDR working so how do I get a refund to my annual emby subscription?







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