Live and background transcodes run at the same CPU priority

[ghost]

Describe the current behavior

All ffmpeg instances run reniced to +15, including the transcodes necessary for live streams. If those fall behind, the stream lags increasingly.

Steps to reproduce:

1. Upload some video
2. Start a live stream
3. Observe process priorities

Describe the expected behavior

I'd expect that both ffmpeg instances would run at lower than default priorities, but that the live ffmpegs would be prioritized higher than the background jobs.

Additional information

• PeerTube instance:

  • URL: diode.zone
  • version: 3.0.0
  • NodeJS version:
  • Ffmpeg version:

• Browser name, version and platforms on which you could reproduce the bug:

• Link to browser console log if relevant:

• Link to server log if relevant (journalctl or /var/www/peertube/storage/logs/):