MOV to MP4 Converter

Is MOV to MP4 lossless?

For most MOV files, yes. A MOV shot on an iPhone, a mirrorless camera or a screen recorder almost always holds H.264 or HEVC video with AAC sound, and all of those are already legal inside an MP4. When that is the case this converter swaps the wrapper and copies the streams through untouched - a remux. Nothing is decoded, nothing is re-encoded, and the picture in the MP4 is bit-for-bit the same as the picture in the MOV.

It is also fast in a way a re-encode never is. Copying is limited by how quickly your machine moves bytes, not by how quickly it compresses them, so a two-hour recording finishes in about the same few seconds as a two-minute one. The tool works this out before you commit: drop a file in and it reads the header, shows the video codec and profile, resolution, frame rate, length, audio codec and size, then states whether it is about to copy your streams or re-encode them, and why. The lossless claim on this page is one you can check on your own file.

What actually separates MOV from MP4

Less than the two extensions suggest. MP4 was standardised out of Apple's QuickTime File Format, and both store everything in nested boxes - Apple calls them atoms - with the same four-character names: ftyp, moov, trak, mdat. At the byte level a remux is mostly a matter of rewriting the index and stamping a different brand into the ftyp box at the front.

The difference that matters is what each container is allowed to carry. QuickTime is Apple's working format, so it accepts things a general-purpose player was never built for: ProRes, Apple Animation, uncompressed PCM audio, alpha channels, several timecode tracks. MP4 is the narrower, standardised set that phones, TVs, browsers, editors, upload forms and car stereos have all agreed on. Converting is not about improving the file; it is about putting it in the box everything else recognises.

The HEVC row is the one that catches people out. Copying an iPhone MOV into an MP4 gives you a genuine MP4, but the codec inside it is unchanged, so a Windows machine without an HEVC decoder or an older Android phone will still refuse it. If that is your problem, the container was never the issue - use the HEVC to H.264 converter instead, which re-encodes the picture into the codec everything can play, and read why HEVC fails on Windows 11 before you decide.

Why the MOV is failing in the first place

Nobody converts a working file. Every search that lands here is a variation on one thing: something in the chain has decided it does not do .mov.

• Windows. QuickTime for Windows was retired in 2016, and although modern Windows plays plenty of MOVs, editors, upload forms and older applications still reject the extension outright. The full explanation is here.
• Android. An iPhone clip sent to an Android phone frequently arrives as something the gallery will not open - usually a codec problem wearing a container problem's clothes.
• Editors and slide decks. Premiere, Resolve and PowerPoint each have their own opinions about which MOV variants they will import, and an MP4 sidesteps most of them.
• Anything with a USB port. Car stereos, TVs and photo frames tend to scan for .mp4 and ignore everything else.

In each case the remux is the right move: the compatible container, without paying a generation of quality for it.

When MOV to MP4 is a real re-encode

Four situations force the encoder to run, and the tool says so before it starts:

1. The video is ProRes, Animation or another editing codec that MP4 cannot hold.
2. The audio is PCM. Here only the sound is re-encoded, to AAC; every video frame is still copied straight across.
3. You change resolution or frame rate in Advanced options. Both mean rebuilding frames.
4. You pick Low, Medium or High instead of the No re-encode chip - usually because you want a smaller file, not a different container.

A re-encode is never lossless, whatever the quality label says, so only ask for one when you actually want it. When you do, the presets are constant-quality CRF values - 20, 23 and 28 for High, Medium and Low - which means the file comes out only as large as the footage needs rather than padded to a fixed bitrate. High is visually close to the source on ordinary phone footage. If shrinking a file is the whole point, our notes on converting MOV without visible quality loss explain which setting to reach for.

What travels across, and what gets dropped

Kept: the first video track, the first audio track, the timing information, and the rotation flag that tells a player your clip was shot upright. MP4 output is written with the index moved to the front of the file, so it starts playing while it is still downloading - which is why a converted MP4 often behaves better in a browser or a chat app than the original did.

Dropped: subtitle tracks, extra audio tracks beyond the first, and container-specific metadata with no MP4 equivalent. The tool counts those during the probe and warns you before conversion rather than after. The phone app drops them too. If keeping every track matters more than compatibility, Matroska is the container built to hold everything, and if you need the file back in QuickTime later, MP4 to MOV is the same instant copy in reverse.

No watermark, no sign-up, no upload

There is nothing to remove and no account to make. The conversion is done by FFmpeg compiled to WebAssembly and running in this tab, so your video is opened by your own browser, on your own machine, and never travels anywhere. That is an architectural fact rather than a promise in a privacy policy: a file that is never transmitted cannot be stored, retained or leaked. Once your first conversion has fetched the engine, you can disconnect from the network entirely and the converter still works.

Most online converters work the other way round because they have to: the conversion happens on their servers, so your file must go up and come back down. That is what the queue times, size ceilings and sign-up walls of free tiers are paying for. There is no queue here because there is no shared machine to queue for. For the longer version of that argument, see whether online video converters are safe.

The honest limits, and when to use the app instead

A browser tab is not infinite. Files over 2 GB are refused, because a 32-bit WebAssembly heap cannot address them. Above roughly 300 MB you get a warning: conversion needs about three times the file size in free memory. The FFmpeg build here is also single-threaded, so a genuine re-encode is slow - roughly real time for 720p, slower than real time for 1080p, and several times worse again for H.265. None of that applies to a remux, which stays near-instant however long the video is, and for MOV to MP4 most people never touch the slow path.

When the slow path is unavoidable - a long 4K clip, anything past the 2 GB line - the phone app is the better tool. It uses FFmpeg with your device's own hardware encoder, VideoToolbox on iPhone and MediaCodec on Android, which is a different order of speed from anything a browser reaches, and it has no size ceiling. It always re-encodes, though, so it cannot do the lossless copy this page does. The iPhone walkthrough covers doing the job entirely on the phone, and the app page has the rest.