I just did a capture with kdenlive and cheese, use a Logitech Pro 9000.
What is the make/model of the webcam you're using?
What did you use Cheese for? Pre-record the video, save to a file and then import it into Kdenlive?
No, just testing my webcam, and seeing if it would record, with a basic application.
Kdenlive is supposed to be able to record from the webcam ...... which it will do ..... but won't record the sound from the webcam MIC.
Also it plays back the video at what appears to be 2x speed.
I am looking for an app that will record both video and sound and then allow me to edit it.
Sound came in fine, once I adjusted the proper source in
kdenlive.
Webcam is working fine
ID 04f2:a147 Chicony Electronics Co., Ltd
regards.

Not sure what else to suggest, off the top of my head...I'll see what percolates in my head after a while...

Do you know what driver(s) your webcam uses? Mine is using
uvcvideo and
snd_usb_audio.