Hardware transcoding problem with subtitles

[RandonOrty 0]

Hi there,

 

Happy user of Emby, I am facing a problem with hardware transcoding since a few days.

 

When I play a video, which need to be transcoded, everything works fine if there are no subtitles. Hardware transcoding (Intel Quick Sync) do the job, transcoding go faster than playing, my integrated GPU work hard, everything is fine. But if I add subtitles to the play, the hardware transcoding goes a lot slower, so the video stuck frequently because the transcoding is not fast enough.

 

I got the problem with all my players (Web player on Edge and Chrome, Emby on my Shield TV or on my smartphone).

 

Info about my computer:

• Proc: Intel Core I5-9600K
• Mem: 16 Go DDR4
• SSD: Samsung SSD Evo Plus 250Go
• OS: Windows 10 1909 (18363.752)

Info about my Emby Server:

• Emby Premiere: yes
• Hardware transcode: yes

 

Here some screenshots about a test with a HEVC encoded file with and without subtitles. I play the file remotely through the web player.

You can find log files attached.

 

Without subtitles, everything fine

 

 

 

With subtitles, slow hardware transcoding

 

Do you know what can cause this performance issue?

 

Thanks' and keep up the good work

 

PS: that's my first post, I hope I did it correctly !

embyserver.txt

ffmpeg-transcode-wo_subtitles.txt

ffmpeg-transcode-with_subtitles.txt

[Luke 42080]

Hi there, did you take a look at the troubleshooting section at the bottom of our hardware acceleration setup guide?

https://support.emby.media/support/solutions/articles/44001160148-hardware-acceleration-overview

[RandonOrty 0]

Hi Luke,

 

Thank you for you quick reply. Yes, a look at the article and I get the point with the integrated subtitles.

 

What I don't understand is :

- i don't have any activity peak on my CPU when I add the subtitles. With or without subtitiles, the CPU usage is about 15-20%

- when I disable hardware acceleration, my CPU handle well the transcoding with subtitles.

 

It seems that the CPU is not well used with hardware acceleration and subtitles.

[Luke 42080]

@@softworkz may have some insight on that.

[RandonOrty 0]

Here some tests I have done:

Try with or without the option “Allow subtitles extraction on the fly” (hope my translation is good )

 

Enable advanced hardware acceleration and try the three different methods. Only Quick Sync seems to work. D3D11 et DX11VA failed and Emby fallback to software transcode.

 

If I disable hardware acceleration for decoding part and keep it enable for encoding part, the process is fast.

 

Don’t know if it can help

Edited April 4, 2020 by RandonOrty

[softworkz 5071]

Moving data back and forth between system and GPU memory comes at some cost, and burning-in subtitles is currently done by the CPU only.

In the future, we're planning to do the overlay in the GPU hardware as well.

[RandonOrty 0]

Thanks softworkz,

So for my case, I will stay with software decode and hardware encode. It seems to be the best scenario, using both my CPU and GPU at 70%.

 

A little bit sad not being  able to only use hardware transcode and free up my CPU. I'll wait the update

 

Thanks guyz

[eyeSome 1]

Hey Guys,

 

it's the same for me with emby v4.4.2.0 on Synology DS918+

 

Some movies (h264) with forced subs are going crazy and need to be transcoded because of unsupported subtitles. For me the transcoding performance is horrible (3fps) what makes looking the movie with subtitles enabled impossible. 

 

Is there any way to have the subtitles "supported"? Can I replace them with working ones? 

 

Regards,

eyeSome

[Luke 42080]

Hey Guys,

 

it's the same for me with emby v4.4.2.0 on Synology DS918+

 

Some movies (h264) with forced subs are going crazy and need to be transcoded because of unsupported subtitles. For me the transcoding performance is horrible (3fps) what makes looking the movie with subtitles enabled impossible. 

 

Is there any way to have the subtitles "supported"? Can I replace them with working ones? 

 

Regards,

eyeSome

 

I would suggest either playing with Emby apps that can direct play the subtitles such as android or iOS, or download external srt subtitles. Our subtitle download features can help with that.

[RandonOrty 0]

Hey guyz,

 

Quick post to tell you that my problem have been solved. I think it's due to a driver update. (or Emby update ?)

I can know enable hardware transcoding with great performance.

 

Cheers

[Luke 42080]

Thanks for the feedback !