Problem with transcoding DTS with Emby Docker image

[ldnrvio0n934 0]

Hi, I run Emby in docker (official emby/embyserver) under Ubuntu on a Intel NUC8i5. I have Premiere and have enabled VAAPI which is working. There's a strange thing going on when I play 4K movies with DTS on Android TV and Xbox ONE though. It direct streams the video and transcode the audio stream to AC3 which should be correct. There's however a spike on just 1 CPU (out of 8) which is maxed out and the Movie isn't playable, it stutters.  When I select an AC3 stream in the client there's no stuttering.

 

Please see attached logs.

embylog.zip

Edited March 27, 2019 by ldnrvio0n934

[Luke 37248]

Hi there, if you lower the in-app quality setting to force a full transcode, does this still happen?

[ldnrvio0n934 0]

Hi there, if you lower the in-app quality setting to force a full transcode, does this still happen?

 

Hi, there's no stuttering when I force transcode.

[ldnrvio0n934 0]

Hi, this is my docker-compose.yml if it helps:

version: "2.3"
services:
    emby:
      image: emby/embyserver:beta
      mem_limit: 8g
      cpus: 8
      privileged: true
      ports:
      - "8096:8096"
      volumes:
      - /media/aa/embyconf:/config
      - /media/aa/media:/mnt/
      - /media/aa/tmp:/mnt/media_tmp
      - /media/aa/tmp:/mnt_tmp
      devices:
      - /dev/dri/renderD128:/dev/dri/renderD128
      environment:
      - UID=1000
      - GID=1000
      - GIDLIST=44
      - TZ="Europe/Brussels"

[ldnrvio0n934 0]

Hi, I installed the Ubuntu version instead and it's the same situation. When I do "top" one can see that ffmpeg maxes out a CPU.

[Luke 37248]

Hi, that's just the nature of ffmepg as it will go as fast as it can. Did you try enabling the throttling option in the transcoding section of the server dashboard?

[ldnrvio0n934 0]

Hi, but shouldn't ffmpeg distribute the load on several CPUs? Is it compiled properly for dts->ac3 transcoding?

 

Throttling doesn't solve the stuttering.

[Luke 37248]

 

 

Hi, but shouldn't ffmpeg distribute the load on several CPUs?

 

Yes, in theory, but this depends on how optimized the decoding & encoding algorithms are for multi-threaded use. Yes it is compiled properly.

 

Can you try lowering the in-app quality setting? thanks.

[ldnrvio0n934 0]

Can you try lowering the in-app quality setting? thanks.

 

But I wan't to direct stream the video and transcode just the audio. That setting affects the video stream.

 

Is the audio transcoding hw-accelerated at all?

[Luke 37248]

 

 

Is the audio transcoding hw-accelerated at all?

 

No, it's not.

[Luke 37248]

We're also about to release Emby Server 4.1 so you could try that once available and see how that compares. Thanks.