OBS Output to Zoom Webinar - Quality Issues

S

scottg

New Member
Wondering if anyone has had any luck with picture quality going out of OBS into Zoom, My sources into OBS are an ATEM Mini with live cameras and 1080p Keynote slides (lots of fine detail in the slides) as well as video pre-rolls that are also heavy with fine detail graphics. The audiences for the Zoom meetings are in the 100 - 200 participant range. I'm also overlaying featured questions from the Zoom Q&A using Social Stream Ninja and these are 90 minute streams.

When I go out of OBS as a virtual webcam, Zoom hammers the video stream. Looks muddy and ragged and it destroys any fine detail in onscreen text. I've read of people sharing the Program Output of OBS as a fullscreen projector window on a second display and sharing that via screen sharing on Zoom. Anyone have luck with that. My testing of that was a mess – much better picture quality, but poor framerate, challenges with drifting audio sync, issues with audio echo and the workflow is much more precarious from the Zoom end.

Anyone in similar circumstances find a good solution?

Thanks in advance for any feedback!
 
Hello Scott, try Zoom support.

Requirements for HD video for meetings:

Full HD (1080p)
  • Pro (with Zoom Events or Zoom Webinars Plus license), Business, Education, or Enterprise account
  • Setting must be enabled by Zoom Support ...
 
krlosgaleano said:
Hello Scott, try Zoom support.

Requirements for HD video for meetings:

Full HD (1080p)
  • Pro (with Zoom Events or Zoom Webinars Plus license), Business, Education, or Enterprise account
  • Setting must be enabled by Zoom Support ...
Click to expand...
Yeah, the client already upgraded their Zoom account and contacted Zoom and enabled HD. It's not a resolution thing - the virtual camera is going out at 1080p. It's just getting overly compressed. I was able to try two streams using the Screen Share option in Zoom, but several times throughout the90 minute stream the audio drifted out of sync. It would drift back closer to proper sync, but would never stabilize. The image looked much, much better resolution-wise. There was some minor frame dropping, but it was worth it for the improved image quality.
 
The screen share approach is the right idea, the bitrate ceiling for virtual camera in Zoom is brutal compared to screen share. For the audio drift issue you saw, try running OBS Fullscreen Projector on a second display and share that in Zoom with "Optimize for video" checked. Route all audio through OBS monitoring output to the same device Zoom is using instead of relying on desktop audio passthrough.

fwiw I do a lot of keynote-heavy presentations and started using a live zoom tool (TuringShot) to magnify specific slide sections while presenting. Even through Zoom compression the zoomed content stays readable because it fills more of the frame. Helps a ton with fine-detail slides.
 
turingsroot said:
The screen share approach is the right idea, the bitrate ceiling for virtual camera in Zoom is brutal compared to screen share. For the audio drift issue you saw, try running OBS Fullscreen Projector on a second display and share that in Zoom with "Optimize for video" checked. Route all audio through OBS monitoring output to the same device Zoom is using instead of relying on desktop audio passthrough.

fwiw I do a lot of keynote-heavy presentations and started using a live zoom tool (TuringShot) to magnify specific slide sections while presenting. Even through Zoom compression the zoomed content stays readable because it fills more of the frame. Helps a ton with fine-detail slides.
Click to expand...
Yes, I was sharing a Preview Projector window out of OBS fullscreen to a 1080p monitor. And the audio was going direct out of OBS to Zoom with audio and optimize for video turned on. The audio drift seems to be introduced when the Zoom compression chokes a bit on a complex image. It's not super bad...and it's not constant. It's maybe a few frames out of sync for a few minutes... then it re-syncs itself (roughly) again.
 
The drift is happening because Zoom ties audio and video together in the screen share pipeline, so when it drops frames to handle a complex image the audio timing gets nudged along with it. Try routing your OBS audio through BlackHole into Zoom's microphone input instead of using the "Share Computer Sound" checkbox. That way audio and video travel through completely separate Zoom channels and the video compression can't mess with your sync anymore.
 
That's
turingsroot said:
The drift is happening because Zoom ties audio and video together in the screen share pipeline, so when it drops frames to handle a complex image the audio timing gets nudged along with it. Try routing your OBS audio through BlackHole into Zoom's microphone input instead of using the "Share Computer Sound" checkbox. That way audio and video travel through completely separate Zoom channels and the video compression can't mess with your sync anymore.
Click to expand...

Thanks - That's an interesting thought. However, as soon as I "unmarry" the audio and video streams, there's most likely going to be a sync issue from the outset. Which i would have to correct for... but hopefully the offset would remain constant throughout the stream. Worth checking out. Oddly, when I spot checked the recording that Zoom made on their end, the audio sync issue is not apparent in their recording file. It's solid throughout. So the sync issue is definitely happening on Zoom's end after they receive the stream from me. I'm looking into alternatives to Zoom that will stream the OBS virtual cam signal at full resolution/high bitrate (Livestorm, Contrast, Goldcast) that would also add some audience engagement doo-dads as a bonus.
 
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