Same length videos now have much larger file size

R

rblack7064

New Member
I use OBS to record my uni lectures, with a 1 1/2 hour class normally having a 300-400mb file size. Now, for some reason, recordings of the same length have a file size of about 1.8gb. Does anyone know what could be causing this/how to reduce the file size again? I haven't changed the settings or anything (as far as I know)

Another weird thing is that the file size varies quite a lot for similar length videos. E.g. a 1hr 55 minutes long video from last week is 1.21gb, and another 1hr 59 min video from today is 2.19gb. So there's a four minute difference in the video length, and a one gigabyte difference in the size.

Thanks in advance for the help

I've included a log file but not sure if it's any use as the problem started a while back
 
According to your log, you're recording with a constant bitrate of 2500 kbit/s.
2 hours recording with 2500 kbit/s is 2 hours * 60 minutes * 60 seconds * 2500 kbit/s / 8 bit = 2250000 kbyte = 2.25 gig. This is the exact size of the video to expect.
You mentioned a 1 hour 55 minute video with a size of 1.21 gig.
This is a bitrate of 1210 mbyte / ((1 hour * 60 minutes + 55 minutes) * 60 minutes) * 8 bit * 1000 kbyte/mbyte = 1403 kbit/s.
So you previously used a bitrate of about 1400 instead of 2500 for this previous video. This will give mediocre quality, even worse than the already not very good 2500.

If your recordings have low or almost no motion, it's better to not use the streaming settings for recording but the recording settings. Depending on the amount of motion, the recordings might get smaller, because no space is used if the image doesn't change.
Change recording quality from "same as stream" to "high quality, medium file size" and as encoder use Hardware (QSV) if possible, otherwise Software (x264), then compare the file size. For mostly static video, size will be considerably smaller.
 
Thank you for your reply. Have just changed the recording quality and encoder as you said, the next class I'm recording is on Friday so will see then if it's back to normal. Is there anything else I can do to reduce the quality? The videos don't need to be ultra clear or anything, as long as I can hear and see what's going on that's enough.
 
Hi again, just wanted to say thanks so much for your help, video file sizes are now back to how they were before
Thank you!
 
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