- Does converting MOV to MP4 lower the quality?
- Almost never. MOV and MP4 are containers — they hold video and audio but don't decide how it's compressed. When the video inside is H.264, H.265, AV1, or VP9, this tool copies it into the MP4 bit for bit, the same way you'd move a file into a different folder. Audio in AAC, MP3, Dolby Digital, Opus, or FLAC is copied the same way. The only track that gets re-encoded is uncompressed PCM audio, which MP4 has no standard slot for, and the AAC that replaces it at 192 kbps is transparent for speech and all but indistinguishable for music. The plan shows you exactly which case your file is in before you click Convert.
- Why won't my MOV play on Windows or Android in the first place?
- It's the container, not the video. MOV is Apple's format, and while modern Windows can often open one, plenty of software still refuses on sight — older editing apps, upload forms that check the file extension, TVs, projectors, and most Android media players. The frustrating part is that the H.264 video inside would play fine on all of them. Rewrapping it as MP4 changes the label on the box without touching what's in it, which is why this takes seconds rather than the half hour a real re-encode would.
- Is my video uploaded anywhere?
- No. The page reads the MOV from your disk in small pieces and builds the MP4 on your device. You can open your browser's network tab while it runs and watch — the video isn't sent to any server. That's also what makes large files practical: nothing has to travel over the internet, in either direction. An 8 GB camera file would take well over an hour just to upload to a typical online converter before it even started working.
- It says my MOV uses ProRes. What do I do?
- ProRes is Apple's professional editing format, and it's the single most common reason a MOV can't be converted in a browser — no browser ships a ProRes decoder, so there's nothing to copy and nothing to re-encode from. You'll see it on footage from Final Cut Pro, an ATOMOS recorder, a BlackMagic camera, or an iPhone 15 Pro or later shooting in ProRes mode. The fix is to export H.264 from whatever app made the file, which every one of those apps can do, or run it through a desktop converter like HandBrake. The same applies to the other Apple-era formats you occasionally find in old MOVs: Apple Animation, DV, and Motion JPEG.
- Why did my file get smaller?
- Because of the audio. Cameras, field recorders, and QuickTime screen recordings made before macOS Catalina commonly store sound as linear PCM — completely uncompressed. A stereo 48 kHz 24-bit PCM track runs about 2.3 megabits per second; the AAC that replaces it runs 192 kilobits. Over a ten-minute clip that's roughly 150 MB of pure overhead removed, and on long recordings it can be gigabytes. If your MOV already has AAC audio, nothing shrinks and the estimate will say the size stays about the same.
- What's the biggest file I can convert?
- In desktop Chrome and Edge, up to 64 GB — enough for a long take off a camera card. Those browsers can write the MP4 straight to a file on your disk, so the video is never held in memory. Other browsers, including Safari, Firefox, and every phone browser, have to build the MP4 in memory before offering the download, and holding a second copy of a large video can crash the tab, so the limit there is 2 GB. If your file is bigger, open this page in Chrome or Edge on a computer.
- My iPhone video is a MOV. Will this work on it?
- Yes, and it's the easiest case there is. iPhones record H.264 or, since iOS 11 in High Efficiency mode, H.265 — both of which MP4 carries natively, so every track gets copied and the quality is untouched. One thing to know about H.265: it plays on iPhones, Macs, Android, and most TVs, but some Windows PCs need Microsoft's HEVC extension installed first. The tool shows a note when your file is H.265 so that doesn't catch you out after you've sent it to someone.
- My MOV has several audio tracks. Which ones end up in the MP4?
- All of them that MP4 can carry, in the same order. Multi-camera and multi-mic shoots often produce a MOV with separate tracks per source, and the MP4 keeps each one so an editor can still split them out. Apple Lossless is the exception — browsers can't decode ALAC, so those tracks are left out, and the plan tells you which track numbers are affected before you convert rather than after.
