Why iPhone videos won't play everywhere — and how to fix it
Updated · 4 min read
The video plays perfectly on your iPhone, then a Windows PC shows a black screen, a TV says the format isn't supported, or an upload form rejects the file outright. Usually nothing is wrong with the video. It's a mismatch between how the iPhone saved it and what the other device or site expects — and the fix depends on which part is the problem.
Container vs codec: two different problems
Every video file has two layers. The container is the box — MOV, MP4, MKV or WebM — and it's what the file extension tells you. Inside the box, the picture is compressed with a codec, such as H.264 (also called AVC) or HEVC (also called H.265). A player needs to understand both.
iPhones save videos as MOV files. With the camera's default High Efficiency setting, the picture inside is HEVC, which gives smaller files than H.264 at the same quality. Apple devices play both without a second thought, but not everything else does:
- The container is the problem when a site or app refuses the file before even trying it — an upload form that only lists MP4, or an editor that doesn't open .mov files.
- The codec is the problem when the file opens but the picture doesn't: a black screen with sound, a message about a missing codec, or a TV that lists the file and then won't play it. On many Windows PCs, HEVC playback depends on an extra codec extension, and older TVs and players often can't decode it at all.
Check what's inside your video
Before converting anything, find out which case you have. Video Info reads a file in your browser and lists its file type, duration, size, overall bitrate, video codec, resolution, rotation, frame rate and audio details — handy when an app or site rejects a file without saying why.
| Video codec shown | What it is | Plays widely? |
|---|---|---|
| avc | H.264 | Yes — phones, computers, TVs, editors and upload sites |
| hevc | HEVC / H.265 | On Apple devices and many newer ones; often not on older PCs, TVs and players |
Nothing to set — add the file and read the details.
What MOV to MP4 conversion does here
Video Converter changes the container. When the video and sound inside can go straight into the new format, they're copied as they are — fast and lossless — and only re-encoded when they have to be. MP4 can hold both H.264 and HEVC, so an iPhone MOV becomes an MP4 with the same picture inside. The ready-made MOV to MP4 page has MP4 already selected.
That solves container problems: the site that only accepts .mp4 will now take it, with no loss of quality. It doesn't change the codec, though — an HEVC video is still HEVC afterwards, so a player that can't decode HEVC still won't play it. If Video Info showed avc, converting to MP4 is all you need. If it showed hevc and the problem is playback, read on.
When you need H.264: re-encode the video
Getting from HEVC to H.264 means decoding every frame and encoding it again. Compress Video always does this and always writes an MP4. It uses the most widely supported codec the browser can encode — H.264 first — so in practice the result is an H.264 MP4. Check it afterwards with Video Info to be sure.
- Open Compress Video and add the iPhone video.
- Set Quality to High to keep as much detail as possible.
- Leave Resolution on Keep original, or choose 1080p for 4K clips — 1080p is sharp on phones and laptops and makes a much smaller file.
- Click Compress, download the MP4, and check the codec with Video Info.
Two things to know. First, the browser has to be able to decode HEVC to re-encode it: Safari, or Chrome or Edge on a computer with HEVC support, usually can; if yours can't, you get a clear message rather than a broken file. Second, H.264 needs more data than HEVC for the same quality, so at full resolution the result can come out no smaller than the original — in that case Compress Video tells you instead of handing you a bigger file. Choosing 1080p usually gets past that.
Tip: Re-encoding costs a little quality, while changing only the container doesn't. Use Video Converter when the container is the problem, and re-encode only when the codec is.
Stop it happening: the Most Compatible setting
If you regularly share videos with Windows PCs, TVs or sites that struggle with HEVC, change the camera setting on the iPhone: Settings › Camera › Formats › Most Compatible. New videos are then recorded in H.264 (and new photos as JPEG instead of HEIC). Files are larger, and some high-resolution or high-frame-rate recording modes are only available with High Efficiency. Videos you've already recorded aren't changed — those still need converting.
If a video plays but appears sideways, that's a different issue: the rotation is stored as information the player is supposed to follow. Video Info shows the rotation, and Rotate Video turns it the right way up.
Questions
Will converting MOV to MP4 lower the quality?
Not with Video Converter when the streams can be copied, which is the usual case for iPhone videos — the picture and sound are moved into the new container untouched. Re-encoding to H.264 with Compress Video does process the video again, so set Quality to High.
Why does it say my browser can't decode the video?
iPhones often record HEVC (H.265), which some browsers can't decode. Safari, or Chrome or Edge on a computer with HEVC support, usually can — try one of those.
Is my video uploaded?
No. Video Info, Video Converter and Compress Video all run in your browser, so the file stays on your device.