Question / Help Are these settings internally sensible?

[DicePower]

Heya, just setup OBS MP for the first time, and I was wondering if my setting choices are reasonable relative to each other (obviously their relation to the hardware would be an external factor, which I understand requires testing). Any tips are much appreciated.

 

[sam686]

Your streaming settings looks ok, but your recording bit rate may be too low for 1920x1080 and "UltraFast". You can raise your recording bit rate to maybe 8000 or even higher if you want, while keeping your streaming bit rate unchanged.

 

[Harold]

Actually, buffer size on recording should be at 0 with crf set to 15-18 and x264 preset set to ultrafast.

 

[DicePower]

Your streaming settings looks ok, but your recording bit rate may be too low for 1920x1080 and "UltraFast". You can raise your recording bit rate to maybe 8000 or even higher if you want, while keeping your streaming bit rate unchanged.

9001 for the memes!

Actually, buffer size on recording should be at 0 with crf set to 15-18 and x264 preset set to ultrafast.

Hmmm, I think I have all of that except the 0 buffer size. I'd heard the buffer size should almost always be the same as the bitrate?

 

[Harold]

Only for streaming.

When recording using CRF based bitrate selection, it needs to be 0 to allow the encoder the ability to choose the necessary bitrate.

 

[sam686]

Even with CRF, it still partially uses the bitrate that is set. Only by adding in qp=18 for advanced x264 options will it then use a constant quality mode that ignores the bitrate. lower qp = better quality at the cost of bigger size. May need to do some testing until happy with the results.

Constant bitrate mode is needed for streaming in which the quality suffers at high motion.
Constant quality mode can keep the high motion at the same good quality, which can be used for recording.

You may try using hardware encoders for recordings to take some load off the CPU if possible, which itself may have different options. Hardware encoder might produce better quality then using x264 at "UltraFast", if your CPU too weak to use slower CPU presets.

 

[Harold]

Only by adding in qp=18 for advanced x264 options will it then use a constant quality mode that ignores the bitrate.

Based on what exactly? CRF based bitrate selection works fine AND ignores the bitrate without any custom x264 options.

https://www.dropbox.com/s/suo2qdn5tu6rfo9/Screenshot 2015-10-16 14.18.04.png?dl=0

 

[sam686]

With more testing, you might be right, but CRF works only if "Use Custom Buffer Size" is on, and "Buffer Size" is zero, which is why i went with changing the bitrate based on the original post's screenshots from my early testing.

 

[Harold]

but CRF works only if "Use Custom Buffer Size" is on, and "Buffer Size" is zero

Which ALL of the recording guides on the forums specifically mention.