Audio transcoding hammering my CPU. Video is on the GPU.

[matticas 3]

Hi there;

I have recently allowed 3 friends to use my Emby.  (milestone?!  ).  One of the users is using Safari and I think Emby on a Amazone Firestick thing.  When he watches almost anything, the audio transcoding is hammering my CPU usage.

Is there anyway to reduce this, or can audio transcoding be offloaded onto the GPU?

 

Setup;

Ubuntu 24.04, Docker, NPM, Emby.  Nvidia GPU.

Docker;
 

...
runtime: nvidia
...
enviroment:
      - NVIDIA_VISIBLE_DEVICES=all
      - NVIDIA_DRIVER_CAPABILITIES=all
...
devices:
      - /dev/dri:/dev/dri
...

 

Emby Settings;

All preferred Hardware Decoders selected / checked;  MPEG-2, VC-1, H.264 (AVC), H.265(HEVC), VP8, VP9.

All preferred Hardware Encoders selected / checked; H.264(AVC), H.265(HEVC)

Software Encoders - default settings.

Every other setting in advanced checked.

 

 

Observation during playback (Emby Settings Activity Dashboard)

Stream MKV (71mbps) -> HLS (22mbps) Reducing bitrate due to quaility setting

Video 4K Dolby Vision HEVC -> Transcode (H264 22mbps) *hardware icon*,  -> Tone Mapping (Hable)

Audio English TRUEHD 7.1 (Default) -> Transcode (AC3 384 kbps)

Observation during playback (ubuntu top CLI process monitor);

ffmpeg /bin/ffmpeg CPU 556%

 

That high CPU load literally heats up my machine and slows everything down.

Viewing on nearly any other device doesn't have this issue.  Only my mate on his devices.

 

Anyway to reduce audio transcoding or force it onto his end?

Thanks

 

 

 

[pwhodges 2023]

Why do you think it's the audio - that's a low load compared with video.

There has recently been an issue with Tone Mapping being done in software instead of hardware on some systems - could this be your problem?

Paul

[matticas 3]

Hi Paul;

I assumed audio because the emby dashboard indicated the video transcode was done by hardware, and I thought ffmpeg was audio only?

I will attempt to disable tone mapping and see the effects, however the emby tone mapping page states it's on the Nvidia CUDA?  

[GrimReaper 4842]

6 hours ago, matticas said:

Observation during playback (Emby Settings Activity Dashboard)

Stream MKV (71mbps) -> HLS (22mbps) Reducing bitrate due to quaility setting

Video 4K Dolby Vision HEVC -> Transcode (H264 22mbps) *hardware icon*,  -> Tone Mapping (Hable)

Audio English TRUEHD 7.1 (Default) -> Transcode (AC3 384 kbps)

Post ffmpeg log for that session.

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