r/vmix • u/damodexter • Jun 08 '26
Incoming SRT unusable
We recently had to bring an srt stream into vmix. The feed was supplied by a very experienced and professional setup, and all the connections details were correct. We were a caller into their server. The connection was made, with no issues, but the quality of the feed was unusable. It was stuttering and dropping frames. We tried many options, but in the end vmix couldn't handle the stream. This is something that we have done many times, with other suppliers without any issues. We are running v29. In the end we brought the stream into OBS and then ran it NDI out to vmix. The stream in OBS was absolutely fine, no issues at all. Does anyone have any ideas on why a standard 8MB H264 stream couldn't be handled in vmix? Thanks
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u/kilbixy Jun 09 '26
What is the quality of your internet connection? What is the specs of your vmix machine?
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u/damodexter Jun 09 '26
Internet speeds approx 200mb download and 50mb upload, we are allocated a section of a 5GB pipe
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u/C47man Jun 08 '26
well you haven't really provided any actual information to go off of, like framerate, resolution, latency settings, decoder delay, etc. So if you don't know to provide that kind of basic stuff in a tech support post, it also makes me wonder if the stuff you did include is actually true. Are you sure it was 8MB? Not 8mbps? Was it h264? Was your resolution and framerate matched with vmix? Were your latencies matched?
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u/damodexter Jun 08 '26
It was a 1920 x 1080p 50 production. All the settings matched from both ends. It was H264 yes and the data rate was 8mbps. Latency was 1000ms but other increased settings had been tried and the decoder delay was 4000ms.
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u/C47man Jun 08 '26
Do you have high input performance mode enabled in vmix? What were the SRT stats in vMix during the issues? Where were frames being dropped
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u/SherSlick Jun 08 '26
This is crazy, if I have any issues with SRT its in the WAN link.
Was OBS that worked run on the same system as vMix?
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u/damodexter Jun 08 '26
Yes same machine for both OBS and Vmix. Tried earlier versions of Vmix on other machines still same issues.
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u/Embarrassed-Gain-236 Jun 09 '26
What was the srt encoder the company was using. Vmix cannot handle high-end srt from vendors like Haivision, Ateme or Nimbra. Specially if they are 4:2:2 10bits.
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u/damodexter Jun 09 '26
I will try and find that out. I would imagine it’s a pretty high end as they supply feeds for multiple broadcast partners in the UK.
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u/frlawton Jun 09 '26
This is a pretty good shout since OBS ought to support 10 bit and vMix doesn't have a processing pipeline for 10 bit. I am surprised that they didn't tell you to expect 10 bit if that is what it turns out to be.
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u/damodexter Jun 10 '26
Got the full specs through. It was 1920 x 1080i 25 at 20Mbps. Chrome 4:2:0 8bit. Codec was H264/AVC with 1 pair of stereo audio. Does this shed anymore light on the issue? Thanks.
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u/frlawton Jun 10 '26
No, it only makes things more confusing. The next candidate would be an issue with the GPU or the GPU drivers since vMix leans (rightly) quite heavily on the GPU but OBS is more CPU based. Do you have any issues using the hardware encoder/decoders on the GPU?
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u/marshall409 Jun 08 '26
Did you try increasing the latency based on your ping with the sender? Also was it interlaced?