I already looked for information about the developer. 

philsmith2004 wrote:

...and have better additional information of what library is used for the "Record" option of CinGG.

No, I am sorry. I don't use Record tool. I can try, if you want.

who could have developed it?

Adam William developed Cinelerra (originally Broadcast 2000) and so I am pretty sure he did.  Many, many others have added to it and fixed problems over the last 22 years.  As well as all of the people who have updated and maintained the libraries to current.

Yes, the libraries to make it work.
I was surprised!

I would think it uses x11grab from FFmpeg, but it has more features!
Almost the same as simplescreenrecorder. is more complex than OBS! who could have developed it?

it is too good! :)

@andreapaz

Not sure if you are seeing this and have better additional information of what library is used for the "Record" option of CinGG.

Does anyone know what library is used to record cinelerra?

Not sure if this is a complicated question OR just obvious to others to look here:

1) in the main window, use the "Settings" pulldown to select "Preferences"

2) then select the "Recording" tab

3) next, if you use the down arrow in the "Audio in" and "Video in" sections under "driver" you will see choices which reflect various driver/library software

uff the recorder works too!
vaapi encodes fine. I have to do more tests.

Does anyone know what library is used to record cinelerra?

Congratulations! on a successful build -- warnings are OK and known/expected.   Because you compiled on your particular computer setup, there may even be some very minor speed improvements (probably not noticeable). 

Vaapi and vdpau work!!!
first time I see nvidia works XD!

Nvidia - Video Engine Utilization 50%+
Intel - intel_gpu_top works and doesn't crash.

I saw many warnings in the build.
but it worked first time. :)

Oh, and then just start the application by keying in: ./cin in the bin subdirectory of /home/USER/cinelerra5/cinelerra-5.1