How do you save computation cycles by NOT EXPORTING/SHARING audio on iMovie

You have asked something that I have never heard in 20 years on these forums.

I don't think your concern is merited as the audio component of a video clip is generally less than 1.0% which is completely negligible.

OK I will give you an answer.

iMovie is a free and comparatively simple editing app which provides all basic requirements.

It does not cover every eventuality and need especially ones which only one person in a million may require.

For editors who need more, there are professional apps like Final Cut Pro.

You may as well complain that your cheap car doesn't perform as well as a Rolls Royce. It's the same principle, you get what you pay (or don't pay) for.

Sorry, I did not answer the question of how I arrived at a figure of below 1%.

Here is the method which you can use yourself if you download the free app MediaInfo which measures the specifications of video clips.

I inserted a typical 1080p iMovie export and got the following results, the 2 relevant figures being the Video and Audio bit rates.

The Video bit rate is 20.0 Mb/s whilst the Audio bit rate is a minute 128 kb/s.

A simple calculation shows that the video is approximately 160 times bigger than the audio which equates to well under 1%

If you are really desperate to export Video Only you need a pro app like Final Cut Pro.

You can see in my screenshot that you have more control over your export options but I reiterate, you are worrying about something that will make no noticeable difference.

Whether or not iMovie "should" have an option to export "video only" is a matter of desire or opinion. The fact is that it does not have that feature. You are free to submit your suggestion directly to Apple -> Product Feedback - Apple

Like Ian, however, I do not see this as a significant means to "save computation cycles." Audio represents only a small (some would say trivial) portion of the total data contained in a video file and the vast majority of the export/rendering time is consumed by handling the video. The small difference in file size and export time with/without audio is a reflection of that reality - you saw that yourself. If you have empirical data proving otherwise, we'd like to see it.

If you really need this option, then Final Cut would be the way to go.

And these aren't the days of the early 2000's when it would take all night to create a DVD. Now, you have plenty of cycles to burn.