You can even use the Quicktime Player to record your iPhone/iPad screen in high-quality via Lightning cable, or to simply view your iOS device on a big screen (with less lag than wireless/AirPlay.)
That's the handiest tip ever - thanks!
This can even be used to sneakily record Snapchat images & movies.
IIRC the "intended" use was to record demos of your apps and games, considering that QT Player got this feature at the same time they introduced video previews to the App Store. :)
I've noticed this feature, but it doesn't allow you to record audio with it too (mic or system sound). Am I missing something/is there a good way to do this?
...the options to record audio, audio and video, or just video are right next to each other.
I can't find the option for audio + screen recording and your picture doesn't show it.
After you click the "New Screen Recording" button a small rectangular window appears. Next to the Record button there is a drop down menu where you can indicate sound input source, as well as things like "Show Mouse Clicks". I recently came across this Quicktime tool. It's really nice, you can even do some simple movie editing with it (trim clips, combine clips etc). I use it to produce demo videos.
in the drop down where you select the iPhone as video source you can also select the iPhone as audio source. I'm not sure if it records the audio output of the iPhone or the microphone input of the phone.
The main problem with quicktime screen recording is that it's terribly slow with a Retina display, because it records at the display's native resolution.
Not really, it captures not video image, but data sent to Quartz. When you play it back, it plays perfectly.