Stream from OBS for less than 1 fps, on purpose - but it doesn't work

Rafferty

New Member
I want to set up OBS to stream with less than 1 fps. (When streaming art or just chatting, we don't need the screen to update more than once a minute.)

OBS 27.2.4 for Win x64 has setup options that allow for less than 1 fps.
File > Settings > Video > Fractional FPS Value
And then set Numerator to 1 and Denominator to 60, or the like.

However, this streaming doesn't actually work. When I press "Start Streaming" the program declares that a connection was made. But the upload light stays gray. (It's never green, yellow, or red.) The timer for "Live" starts and keeps running, but kb/s never changes from 0. No video is actually streamed.

Also strange: When I press "Stop stream", it can take several minutes for OBS to change state from "Stopping Stream..." to returning to a stopped-stream state.

I've found forum threats about recording at less than 1 fps, but none about streaming. Is this behavior unique to me? Does OBS require some unique configuration to make less-than-1fps streaming work?

Thanks in advance for your help.
 

koala

Active Member
This behavior is connected with the low frame rate. Encoding video with h.264, which OBS does, does encoding in groups of pictures (GOP). The group size (or GOP size) is somewhere around 15-30 frames. The encoder cannot stop encoding until it got a complete group of pictures (or frames), so if you click on stop, and it has still an incomplete group of pictures, it waits for a few more frames until it can close the GOP.
If you set your frame rate to 1/60, you get 1 frame every minute (60*1/60)=1. If there are 5 frames missing for the group to complete, it's still 5 minutes for you to wait for the encoder to stop.

Streaming services will probably also wait for at least the first group of pictures to arrive until it acknowledges a running stream. A group of 15 frames with a frame rate of 1/60 requires 15 minutes. I doubt you will wait that long.
 
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