Simulator Stuttering When Capturing Video Through Terminal

Question

I am trying to record a app preview using terminal however whenever I run the terminal command to record video and the simulator, the simulator seems to stutter a lot. This makes the video I get out of it useless. I am running a 2017 MacBook Pro i7 so I don't believe it to be a power issue. The issue is across all the simulators and is thus irrelevant of the device.

I have tried using the .mov and .mp4 extension in terminal to no avail. I noticed that it also says that it has been recomputed for fps at 18. I think this maybe where the problem is. Is there anyway to change this?

If anyone has a possible solution please let me know.

Answer 1

I was just having this same issue. Changing the codec to h264 using the --codec=h264 flag fixed it for me. It's available in version 11.2 of Xcode.

Answer 2

I've come across the same issue when trying to record an iOS app that has animations in it for an App Preview. The video then has moments of lag and the jumps forward.

I didn't find a way around this with using the simulator (the above answer of using the h264 codec didn't work for me), but I was able to get a smooth video capture using a physical device attached to my MacBook with QuickTime Screen Record instead.

Apple's guidance on recording videos as App Preview https://developer.apple.com/support/app-previews/