iPhone video conversion

[Jeikobu]

I hope this is the right place for this.

I have an iPhone 11, newest iOS.

Obviously MOV files take up a good deal of space. I have a lot of videos on my iPhone, and they account for a lot of my used space. Unfortunately iMovie, screen recordings, and camera recordings make everything MOV. I love the quality, but space is becoming an issue.

I got an app today called “Media Converter” on the App Store, and it’s extremely well-rated. I’ve tried to convert a simple MOV video all sorts of ways, but the result always has an unpleasant pixelated quality that shows up through parts of the video.

I don’t expect I’ll be able to have this magic “small size, excellent quality” video, but I’d like better than this, and the old MP4 videos I have that were made that way (they were taken with a digital camera years ago) don’t have that pixelated issue. What should I change?

I’ve gone through all the codecs for MP4. The video has to be MP4 or MOV to work on an iPhone. One thing I was wondering about though is the “pixel format”. Maybe I should experiment with that?

Any help would be appreciated.

[davexnet]

Use the recommended option - this is typical for almost all delivery consumer video

[Cornucopia]

I STRONGLY do not recommend your file conversion idea. Here's why:

MOV and MP4 are merely containers, actually sibling containers. There is almost no difference in their structure - it all REALLY depends on which codecs are in use encapsulated inside them, and size is SOLELY determined by running time & bitrate. MOV in theory allows for a much wider variety of codec choices, but in modern practice MOV basically uses only a few codecs for video, and iPhone uses even fewer variations. In fact, rarely will you ever see anything recorded by an iPhone that is not one of these 3 codecs: ProRes, h264 (aka AVC), and h265 (aka HEVC). Not unsurprisingly, h264 and h265 are the 2 most likely video codecs in use in MP4 containers as well. So it all really comes down to bitrate, and by extension, quality.

In general, all other things being equal, higher bitrate allows for higher quality, lower bitrate only allows for lower quality. Your iPhone is already designed to provide you with one of the best possible qualities for that given bitrate (including using vfr), and if I am not mistaken, my educated guess is that your MOVs are probably already using the h265/HEVC codec, which is currently the MOST efficient codec generally available. You can of course learn this definitively by acquiring the often recommended MediaInfo app, available for iOS, and use it to read your file(s) and list the codecs used and their particular parameters.

Assuming my guess is true, the ONLY way to reduce the size would be to create a converted copy (of the same codec) using a lower bitrate. Doing so often means lowering the quality - are you ok with lowering the quality of your recordings?
There can be exceptions to this in that iPhones do their recordings in realtime, and probably use a dedicated chip for such purposes, and some of those hardware -based, real-time performance options have tradeoffs resulting in higher bitrate than what might be possible with Long GOP, multipass, filtered & optimized software conversion, but this possible modest fiesize savings benefit also comes at the cost of much increased reencoding time. I hardly think it is worth it, especially when you can simply offload your less used recordings to some other storage - drives or cloud.


Scott