Question about file formats and aspect ratio

I noticed something interesting today.

I was filming my screen along with a music keyboard in front of me with my Iphone.
The screen recording comes out as mkv which I convert to m4v.
The Iphone videos comes out as .MOV which usually works with Davinci but seems to be terribly slow.
So this time I converted it into m4v as well.

The weird thing though is that the iPhone video was recorded as vertical and anytime I tried to rotate it in davinci it would get stretched. I've tried all the mismatched resolution settings both in the timeline and the project settings but I could NOT stop it from scaling with rotation.
Then I tried the same thing with the .MOV file and it rotates just fine with the exact same settings....

What is going on there?
Also what can I do to the iPhone video files so they edit better in Davinci?
I'm already using things like proxy timeline and generate optimized media but it still doesn't edit as nicely as the screen recordings from OBS

Your machine obviously has no hardware decoder for H.265, which is now the regular format in iPhones.
In your iPhone, just go for 'Format' in 'Camera' and switch it from 'High Efficiency' to 'Max. Compatibility'.

Ok I'll check that out.

However mind you that I only had issues with the CONVERTED version of that file.
the unconverted worked fine.
So I don't think that's the issue?
Unless I'm wrong about that

You wrote:
"The Iphone videos comes out as .MOV which usually works with Davinci but seems to be terribly slow."
That is probably caused by them being in H.265. The other issue is probably a rotational flag that doesn't survive transcoding. Use the Clip Attributes to turn these.

Sorry for being a bit ignorant but could you explain that a bit further?
So far I only get the very basics that there are differences between file type, and encoding "container"?
I don't know what a rotational flag is though...

What would you recommend to a noob like me for the best editing experience?

Please read about codecs and containers:
https://en.wikipedia.org/wiki/Compariso ... deo_codecs
https://en.wikipedia.org/wiki/Compariso ... er_formats

And then, there is excellent free training by BM:
https://www.blackmagicdesign.com/produc ... e/training

A rotational flag is the information the phone stores in the file regarding how it was held, landscape or portrait.
But if that got lost, use the Clip Attributes as I wrote.

Ok, I'll have a look at those links. Thx!

Regardless of understanding the codecs and such, would changing the flag, as you suggested, also make editing faster and easier? Or should I pre-convert it to a more suitable format?

It is as .MOV super laggy. Like I have to wait a few seconds just to see any clip position/zoom adjustments I'm making, and I have a decent graphics card (Geforce 3060).

That card can't decode H.265 as the iPhone records in hardware. Yes, conversion to ProRes or any other mezzanine codec would help. Changing the flag will only rotate it, but not make things any faster.

And next time switch the iPhone to H.264.