Question / Help Bitrate uncontrollably high?

[PeterF]

I've been using OBS for a while for local recording and it's been great, however today it started recording at abnormally high rates, jumping as high as 10000kb/s and pretty much doubling my filesize. In the Encoding tab my max bitrate is set to 4000, CBR disabled and a custom buffer size of 0.

http://pastebin.com/eFATr0VL <Here's the log file from a short test recording I did.

Any ideas as to what triggered this drastic change and how to fix it?

Thanks in advance

 

[Sapiens]

The whole point of setting a custom buffer size of 0 is to allow the encoder to use whatever bitrate is necessary to achieve your target quality. Spiking to 10 Mbps for a 1080p recording at crf=20 is perfectly reasonable, and simply means that's what the encoder needed for those frames. There is nothing to "fix" because nothing is broken, but if you want to reduce your file sizes you should use a higher crf value.

 

[PeterF]

Thanks for the reply, I'll try to play around with crf or the buffer.

Spiking to 10 Mbps for a 1080p recording at crf=20 is perfectly reasonable, and simply means that's what the encoder needed for those frames. There is nothing to "fix" because nothing is broken, but if you want to reduce your file sizes you should use a higher crf value.

However the thing that bothers me is that my encoder currently seems to require twice as many Mbps (and more importantly twice as much hard drive space) as it did before, recording the same games with the same settings :I

 

[Sapiens]

I recommend looking at past logs to see which settings you may have changed, or simply setting a proper bitrate limit for your videos. Using a value of 0 for the buffer means that your max bitrate setting of 4000 is meaningless - the only thing constraining the bitrate is your crf value. If you're targeting a particular size or maximum bitrate then you shouldn't set a custom buffer value.

 

[PeterF]

FWIW Here's a log from when it was working in what i'd consider the "normal" fashion, can't see any obvious differences :(

http://pastebin.com/JsQYJskw

 

[Sapiens]

Then the content itself is what's driving the encoder to use higher bitrates for certain frames/scenes. Again, completely normal, and this behavior is what you want when configuring the encoding settings the way you have. Output file size should still be totally reasonable, but if it's that much of an issue or you're really hard up for space you should use some actual bitrate constraints.