Server Version#: 1.25.5.5492
Player Version#: Plex Web
Machine Specifications:
Windows 11 Enterprise
64GB Ram
Intel Xeon W-2145 @3.7GHz
1TB SSD
10Gbe NIC
Quadro P4000 GPU
Hello,
I am currently in the process of swapping out my Dell PowerEdge R220 to a newer server with the above specifications. Between the dGPU and the CPU, I thought I’d have plenty of processing power to transcode 4K10-bit HEVC ripped from a Blu-Ray in MKV format but I thought wrong. Currently I am getting freezing every couple minutes when playing a single transcoding stream from a 4k Blu-Ray ripped to MKV via MakeMKV. I am transcoding down to 1080p 10mbps.
When monitoring my Task Manager when transcoding, only CPU 25% is used and the GPU ranges between 15% to 30% so the machine isn’t nearly coming close to its capabilities.
Transcoder quality is set to automatic.
HDR Tone Mapping is enabled.
Use hardware acceleration when available is enabled.
Use hardware-accelerated video encoding is enabled.
I tried playback on the same machine from the web browser as well as from a different machine on the same local network. Both are connected via 10Gbe.
The CPU benchmark score is 18165 which is above what is listed in the support article.
The machine also is a fresh install of Windows and no other applications/services are running. Direct-Play is not an option available to me for this content. Does anybody have any suggestions on what I can do to further troubleshoot? Anybody able to get this type of content transcoded? What’s strange to me is the CPU and GPU are not nearly coming close to being fully utilized yet the stream freezes.
So I’ve narrowed this down to the HDR Tone Mapping. Once I disable it, transcoding is smooth and I can do multiple simultaneous streams. It appears according to HDR to SDR Tone Mapping | Plex Support that NVIDIA GPUs are not supported in Windows for HDR Tone Mapping.
Any plans for this support? Is my only option Linux or Ubuntu inside a docker container?
Upon further troubleshooting this issue, I disabled hardware acceleration and let the CPU transcode the same 4K10-bit HEVC ripped from a Blu-Ray in MKV format down to 1080p 20mbps, and the CPU was at 63% and was transcoding at 1.3x when HDR Tone Mapping was enabled.
When hardware acceleration is enabled, and HDR Tone Mapping is also enabled, my GPU is using 30% and the CPU is also using 30%. The transcode rate is at .9x
When HDR tone mapping is off, GPU is at 30% and CPU is at 15%. The transcode rate is 2.1x.
Based on these numbers, I assume the HDR Tone Mapping is occupying 15% CPU resources.
What I don’t understand here is when hardware acceleration is turned off, the CPU is plenty powerful to handle both the video transcoding and HDR Tone Mapping, but when hardware acceleration is turned on, the Quadro P4000 handling the video transcoding and the CPU handling the HDR Tone Mapping is not capable of transcoding at 1x or greater.
Something is not adding up here and I believe at least on Windows that the HDR Tone Mapping feature is not working as well as it should be when hardware acceleration is enabled and the task is being split between GPU and CPU.
