By default any new iPhone records video in 1080p HD resolution and it does not allow you to change the video resolution. This results in loosing most of the iPhone memory in recording just 20-30 minutes of video.

One minute video with 1080p resolution can occupy more than 100MB memory space. It is difficult to use such huge video for sharing or for transfer purposes.
In many scenarios you do not require full HD video with 1080p resolution and as iPhone doesn’t allow you to change this video resolution setting, you have no way to choose 720p or 480p as desired video recording resolution.
Many people end up with some video resolution converter app or software which allows you to encode your video to a lower resolution later on. However it is very easy to change video resolution of iPhone by using a tiny free app which allows to set resolutions on the fly, it is called- mRecorder.
Size of mRecorder app is only 200Kb however it is fully loaded for video recording task.

Interface is clean and have options to switch between front and back camera, toggle flash setting and at the bottom right corner you have option to change the video resolution.
It support 6 different resolutions for video recording – 1080, 720, 480, 360, 288,144.
mRecorderVideoSettings

 

mRecorder also has an inbuild video player where you can check all your recorded videos.

IMG_3190
Following is a list showing approx size of the video for 1 minute of recording at different resolutions –
1) 1080p – 108 MB
2) 720p- 61 MB
3) 480p- 8 MB
4) 360p – 3.2 MB
5) 288p – 2.6 MB
6) 144p – 900 KB

As I found that for my most of the purposes a video in 480p resolution was good enough, I can now save huge space while recording video and I do not need to convert it as mRecorder directly records video in the selected resolution. No post processing is required.

I would suggest to try recording some sample videos at different resolutions and see which quality suits your needs.

Get mRecorder for free from Apple Store.