Why does VTEncoderXPCService take up all my cpu?

2010 Macbook Pro. Pretty frequently, my mac will spend over 100% cpu on VTEncoderXPCService. It causes the fan to spin up and it causes the computer to get hot.

ps -ef | grep -i vtencoder

shows

01   879     1   0 Mon10PM ??       261:54.85 /System/Library/Frameworks/VideoToolbox.framework/Versions/A/XPCServices/VTEncoderXPCService.xpc/Contents/MacOS/VTEncoderXPCService

which doesn't shed much light on the situation for me.

I'm not doing anything with video when this happens, either.

Any thoughts on what this is doing and/or how I can get it to not heat up my laptop so much?

It seems to be related to pulling movies out of Photos. I had a large movie I was trying to take out of photos to a folder and move to an external drive. This process was using over 300% of CPU for several minutes.

I run into this with the Photos app open, usually when it's syncing media with iCloud. It's especially bad when the sync fails somehow. If you're able to get it to reproduce consistently, maybe send over some information to http://bugreport.apple.com.

I found some answers in a different thread:

https://discussions.apple.com/thread/7303110?start=0&tstart=0

"It's 100% Photos. After reading all the responses I went digging in Photos myself. In my case, I had Photos connecting to iCloud Photo Library in preferences.

The second I removed this connection, VTEncoderXPCService was virtually gone."

I deselected iPhotos in the iCloud management window, and it went away. (Before, I would quit or force quite VTEncoderXPCService and it would just come back.) So far, so good.