Why does iMovie only show MOV as an option in some cases?

The only way to get MOV is by selecting Best (ProRes) as the Quality setting. If you see MOV, check that you did not choose that option. Low, Medium, and High always produce MP4.

Can I change the file extension from .mov to .mp4 manually?

No. Renaming the file does not change the underlying codec. The file will still be in Apple ProRes and will not play correctly as MP4. You must convert it properly.

Does the Compress setting affect whether I get MP4 or MOV?

No. The Compress setting (Faster or Better Quality) affects encoding speed and file size, not the container format. Only the Quality setting determines MP4 vs MOV.

Is there a free way to convert a ProRes MOV to MP4 without installing software?

Yes. The site hdvideoconverter-mac.com converts video to MP4 online without a watermark. You upload your MOV file and download the MP4.

How to Export an iMovie Project as MP4 (Not MOV)

To export an iMovie project as MP4, use the File > Share > File route and select Low, Medium, or High. Those settings produce an .mp4 file with H.264 video. Avoid the Best (ProRes) option, which creates a .mov file in Apple ProRes. Here are the exact steps to get MP4, why iMovie sometimes exports MOV, and what to do if you already have a ProRes MOV file.

The File > Share > File Route

Open your project in iMovie on the Mac. Click File in the menu bar, then choose Share and File. Or click the Share button in the toolbar and select Export File. Either path opens the export dialog where you control the output format.

The dialog has three settings: Resolution, Quality, and Compress. Resolution lets you pick the video size. Compress offers Faster or Better Quality. The Quality setting determines whether you get an MP4 or a MOV file.

Which Quality Setting Gives MP4 vs MOV

In the Quality dropdown, you see four choices: Low, Medium, High, and Best (ProRes). The first three produce an .mp4 file with H.264 video. The fourth choice, Best (ProRes), produces a .mov file in Apple ProRes. ProRes files are very large and intended for editing and archiving, not sharing. For most purposes, choose Low, Medium, or High to get a compact MP4.

Choosing Between Low, Medium, and High

These three MP4 options differ in bitrate and resulting file size. Low creates the smallest file but lower visual clarity. Medium balances size and clarity. High gives the best clarity among the MP4 options but a larger file. For quick sharing or email, Low or Medium works well. For archiving or playback on a large screen, High is the right pick.

Compress Setting

The Compress option has two choices: Faster or Better Quality. Faster encodes more quickly but may produce a slightly larger file. Better Quality takes more time but can reduce file size while keeping the same video clarity. This setting applies to both MP4 and MOV exports.

Confirming Your Export is MP4

After you click Next and name your file, look at the file extension in the save dialog. It will be .mp4 if you chose Low, Medium, or High. It will be .mov if you chose Best (ProRes). If you see .mov, go back and change the Quality setting before exporting again.

Already exported a MOV file? The next section explains what to do.

What If You Already Exported a MOV File?

If you exported your iMovie project as MOV by selecting Best (ProRes) or by accident, you have a large ProRes file. ProRes files are designed for editing and archiving, not for sharing online or via email. Convert that MOV file to MP4 afterwards to make it much smaller. The conversion keeps the video content but changes the codec from ProRes to H.264, drastically reducing file size while retaining good visual clarity.

How to Convert MOV to MP4

Locate the .mov file on your Mac.
Use a video converter that accepts MOV input and outputs MP4. The site hdvideoconverter-mac.com converts video to MP4 online without a watermark.
Upload the MOV file, choose MP4 as the output format, and start the conversion.
Download the resulting MP4 file. It will be much smaller than the original ProRes MOV.

Why IMovie Exports MOV and Why it Matters

iMovie offers the Best (ProRes) setting to preserve maximum detail for further editing. ProRes is a professional codec that maintains high clarity through multiple generations of editing. The tradeoff is file size: a few minutes of ProRes video can be several gigabytes. For final distribution or sharing, an H.264 MP4 is far more practical. Understanding this distinction helps you choose the right export setting.

If you plan to edit the video later in another application, exporting as ProRes MOV might be useful. Otherwise, stick with Low, Medium, or High for MP4.

Summary of Settings for MP4 Export

File > Share > File (or Share button > Export File)
Quality: Low, Medium, or High (not Best ProRes)
Compress: Faster or Better Quality (your choice)
Resolution: Pick your desired size
Result: .mp4 file with H.264 video

If you need to convert an existing MOV, use a converter like hdvideoconverter-mac.com to get an MP4 without a watermark.