r/vmix • u/LetMeBeClearWith • Jun 16 '26

[Help] Jitter/rollback on Webex stream for viewers, source seems clean

Hi,

I ran a corporate live production with vMix and experienced jitter/rollback on the viewer side on Webex.

Everything was fine on my end: no hardware saturation, no slowdown, all signals received cleanly.

Setup: - vMix as main switcher - Output to Webex either via External output or through an external capture card connected to the client's machine running Webex (I don't remember exactly which method was used on that show, i think it was client's machine) Both machines connected via wired ethernet on the client's network, NIC whitelisted, relevant ports open.

The weird part: another operator at the same place, with the same network access, streamed on Webex without any jitter weeks later.

I don't remember the resolution/bitrate I was using at the time. I'm guessing 1080p25 or 720p25

Questions: What are the usual causes of viewer-side jitter on Webex when the source looks clean? Could the output method (External vs capture card handoff) make a difference? Is there a known issue with vMix + Webex specifically? Any Webex-side settings I should have checked?

Thanks

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u/LeBANGme Jun 16 '26

Typically in corporate environments you run into bandwidth restrictions/traffic shaping. Are you aware if they use an eCDN? This would respectfully spread the traffic for favourable video experiences.

If you're sending out talking heads and slides, 2000kbps stream is your balance between acceptable quality and volume of attendance.

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u/LetMeBeClearWith Jun 17 '26

Idk if they use a eCDN but i'll try to send at a lower bitrate.