Why an iPhone MOV Will Not Play, and How to Convert It to MP4
Most iPhone MOVs that will not play hold HEVC video, which many PCs, older phones and web forms cannot open. In ClipCut's Video Converter, drop in the MOV, keep MP4 under Convert to and press Convert video. H.264 is copied in seconds with no quality loss; HEVC is re-encoded to H.264.
Why the MOV will not play
A MOV file is a container: a box that holds a video track, a sound track and some details about them. The box itself is rarely the problem. What matters is how the video inside was compressed, which is called the codec.
iPhones can record in two codecs. HEVC (also called H.265) makes smaller files, and H.264 is older but plays almost everywhere. Apple's Camera settings let you choose between High Efficiency, which records HEVC, and Most Compatible, which records H.264. Apple describes this in its own support pages, and settings can move between iOS versions.
When a computer, an older phone, a TV or a website cannot decode HEVC, you see the usual symptoms: sound with a black picture, a file that will not open at all, or an upload form that rejects the video. Some upload forms also refuse the MOV extension even when the video inside is H.264.
Step by step in ClipCut
1. Open ClipCut's Video Converter (or the MOV to MP4 page) and drop in your MOV. The file stays on your device and is not uploaded.
2. ClipCut reads the file header first. If your browser cannot show a preview, the file details say preview is not available for this format, but conversion still works. That is normal for HEVC in some browsers.
3. In the Convert to row, keep MP4 selected. The other choices are WebM, MOV, MKV and AVI, but MP4 is the safest choice for sharing.
4. Press Convert video (on the MOV to MP4 page the button says Convert to MP4).
5. The result card shows the file size on the Download button. Use Before and After to compare the two, then download. If you want to try another format, press Keep editing.
What the conversion actually does
ClipCut checks the codec before it converts. If the video is already H.264 and the sound is AAC or MP3, it does not re-encode anything. It copies the video and sound into a new MP4 box, which takes seconds and keeps the quality identical to the original.
If the video is HEVC or another codec, ClipCut re-encodes it to H.264 with AAC sound, because that is the combination most players accept. This takes longer, depending on the length and resolution of the clip and on your device. The resolution is not changed.
A re-encoded MP4 is not always smaller. H.264 needs more data than HEVC for a similar picture, so the MP4 can come out about the same size or larger than the MOV. If you need it smaller to send, run the result through Compress Video afterwards.
How to check the result
Play the converted file on the device or site that refused the original. That is the only test that really matters.
Check the length matches the original and that the sound stays in sync to the end. ClipCut also checks every export before offering it and says so if the result comes out empty or will not play in your browser.
If the original was filmed in HDR, look at the colours. ClipCut shows a note when it detects an HDR video, because edits that re-encode it can look duller than the original. For most sharing this is fine, but it is worth a look.
Limits and what to do if it fails
If you see a message that the video uses a codec ClipCut cannot decode yet, the converter cannot help with that file. This happens with some codecs such as AV1, not with normal iPhone HEVC or H.264.
The converter keeps the main video and the first sound track. Extra sound tracks and subtitles are not carried over.
Re-encoding a long 4K video is slow in a browser and can run out of memory on phones. If ClipCut says your browser ran out of memory, close other tabs and try again, or use a laptop or desktop in a modern browser.
Converting cannot add quality the original never had. It only changes how the video is stored.
Only convert footage you own or have permission to use.
Avoid the problem next time
If you often send iPhone videos to people on other devices, you can switch the iPhone camera to Most Compatible so new videos are recorded in H.264. The files will be larger, so it is a trade off, not a rule.
If you keep High Efficiency, converting before you send is quick, and H.264 files you convert later are copied rather than re-encoded, so they keep their full quality.
Try it on your clip
Free in your browser. Nothing is uploaded, and the file is wiped from the page when you close the editor.
Open the Video Converter →