IPhone – measure time by counting frames and trusting the ‘240 FPS’ of the iPhone 7+ slow motion

I'm not sure if you want to know about storage on the iPhone itself, or storage by iTunes in the backups, so I'll take a stab at both. :)

See here for a more in-depth analysis, but the basic gist is that the .mddata files are typically SQLite databases (occasionally encrypted), while the corresponding .mdinfo files are the metadata associated with them. (Older versions of iTunes used .mdbackup files.)

Here's a more practical description of retrieving data from an existing iPhone/iPod backup, and another one which does so with the more recent format. Also, there's this presentation that dives into the format a bit. Here's a blog entry about deciphering the obfuscated filenames, and finally, here's a StackOverflow discussion about decrypting the encrypted .mddata files (which didn't end in a resolution of any kind).

On the iPhone itself, many applications store their data in a SQLite database directly because of the simplicity of doing so. Also, the Core Data ORM uses it under the hood, although that's really just an implementation detail.

But, as you've noted, there's no requirement to use SQLite; applications can store data in something as simple as a plain text file or XML document, or as complicated as a database of their own making.

I guess it depends more on your creativity than on the tools you use. You could do it all with your webcam using Photo Booth, in one take, but then you wouldn't be able to overlay multiple tracks and the audio/video quality would be bad.

The basic gist of it is: first you have to create a basic track, probably with some kind of metronome, so you can use it as a base for the instruments and vocals (note they always have headphones while recording, so they can listen to the base track). Then, for each instrument, set up a camera to capture the video and a quality microphone to record audio.

You can mix the audio together in GarageBand, and then sync the audio with the video you recorded at the same time using iMovie. It's a lot of work and can take a long time, but there's no "secret" to it.

If you want more "pro" tools you could use Logic Studio for audio and Final Cut for video. But for simple videos, I guess it would be overkill.