Transcoding Issues

[Spyderturbo007 19]

System:

Supermicro H8DGU-F

64GB RAM

2 x AMD 6212 Octo Core at 2.60GHz

Transcoding standard bluray works just fine at about 85 - 90 fps.  When I start transcoding 4K, it starts around 33fps and then begins to drop until it reaches about 22fps at which point the stream begins to stutter and freeze.  I've tried with the defaults and have made changes to all of the different transcoding settings with no change.  Subtitles are not enabled during the transcoding process.  The user testing the file for me was Dave if that helps find relevant sections in the log.

I can watch the server and the cores don't typically go above 40-45% usage during the transcoding process.

Thanks!

 

embyserver-63742982400.txt ffmpeg-transcode-feb919f3-dafc-4cfe-8740-b72755a4cabe_1.txt

[Luke 42078]

Hi, it looks like your server just can't transcode this fast enough. Have you considered using our media conversion feature to convert it to a more streaming friendly format ahead of time?

[Spyderturbo007 19]

Is there a reason I'm not seeing all 16 cores pegged?  They are only running around 30-40% when transcoding.

I hadn't explored that option before.  It looks like that can pre-convert the file to a lower quality format and store that next to the original file.  I looked for a screenshot of how that will be presented to the user when choosing the file, but didn't see anything.

Is the conversion a manual process, or can I go in and tell it to "convert everything it finds thats 4K?"

I ordered two 16 core processors and am going to give that a try.  I also see that unRAID can now pass GPU resources through to Docker containers.  I'm going to poke around in the forums and see if anyone has any recommendations for a GPU.  I have a Supermicro server chassis, so space is an issue as is power delivery to GPUs that require additional.

Edited December 9, 2020 by Spyderturbo007

[Luke 42078]

Not all parts of ffmpeg are optimized for that many threads so it's unlikely you'd see all cores maxed out by a single process.

@cayars can go over the conversion feature with youb and point you to the kb article. Thanks.

[Spyderturbo007 19]

I went ahead and converted one as a test.  It appears as though it creates another file and they appear side by side in the interface.  It looks like there is no way to know which one is 4K unless you open up each movie and check the file attributes?

 

 

Edited December 9, 2020 by Spyderturbo007

[Spyderturbo007 19]

So, I'm back trying to get this to work correctly.  I upgraded the server to 2 x 16 core CPUs with a 2.5GHz base clock and a boost to 3.4GHz.

I'm still running into the same issue.  The transcode of 4K material starts out just fine at ~40fps and then slowly degrades down to  ~22fps at which point the buffer is overrun and the video stutters.   The transcoding temp file is on an SSD so I don't see that as being a bottle neck.  I can write to that drive at about 130MB/s.

It just isn't using the CPUs properly.  They are really just sitting there waiting for something to do.

Stream Start:

 

After about 3 minutes

 

CPU utilization

ffmpeg-transcode-c4dfc363-7269-497b-8b43-e8754354371d_1.txt