Pitch Graph

I have choir sample. i want to find loopable part. because pitch is not stable i want to see pitch graph of my sample to select stable part. is it possible?

You could try the spectral view of the wave. With the right zoom parameters it should be possible to see what’s happening, pitch wise.

is this usable?

Try it and you’ll know. Noone else has your choir sample to test with.

i meant, i can not see any useful information on this graph. how do you read pitch information from this graph like on cubase vari audio.

No it’s not as clear as VariAudio, but instead of note values, frequencies do show on the vertical axis. So with your attached picture, the horizontal lines are notes (or harmonics of them), and where the lines aren’t straight it indicates a rising or dropping pitch. At the start of the sample you clearly see a rising pitch. Whether it really is useful is for you to decide, the perfect program for this would be Melodyne.