MOV File (.mov): What It Is, How It Works + Sample Files

The basics

What is a MOV file?

MOV is the file format of Apple's QuickTime. iPhones save their videos as MOV, Macs save screen recordings as MOV, and professional cameras and editing apps use it to carry high-quality ProRes video. Like MP4, a MOV file is a container: it holds one or more tracks (video, audio, timecode, captions) and the index that keeps them in sync, while the compression is done by a codec such as H.264, HEVC or ProRes.

MOV and MP4 are close relatives. When the MPEG committee needed a file format for MPEG-4, it based it on QuickTime, so the two share the same structure of nested atoms (boxes, in MP4 terms) and the same index tables. The differences are in the details: MOV is identified by the brand qt , has a few atoms of its own, and accepts codecs that MP4 doesn't officially carry, such as ProRes and uncompressed PCM audio.

Why it matters

The .mov extension tells you the container, not the codec. A MOV with H.264 inside plays almost anywhere; one with ProRes inside is an editing file that most phones and browsers can't play at all.

Anatomy

What's inside a MOV file

A MOV file is a sequence of atoms: blocks that start with a 4-byte size and a 4-letter type, some of which contain other atoms. MP4 inherited this design and calls them boxes. Here is the atom tree of sample-720p-h264-aac.mov, our 10-second sample, as read from the file. Offsets and sizes are in bytes; a few atoms in the audio track are left out to save space.

sample-720p-h264-aac.mov (atom tree)

offset      size        atom
0           20          ftyp   file type
                               00 00 00 14 66 74 79 70 71 74 20 20
                               00 00 02 00 71 74 20 20
20          12,354      moov   the movie atom: the index
28          108           mvhd   movie header: timescale, duration
136         5,066         trak   track 1: video
144         92              tkhd   1280×720, display matrix
236         36              edts   edit list
272         4,930           mdia
312         45                hdlr   media handler "vide"
357         4,845             minf
385         44                  hdlr   data handler "url "
429         36                  dinf   data reference: this file
465         4,737               stbl   sample table
473         173                   stsd   sample description "avc1" (H.264)
646         24                    stts   timing: 300 frames, equal length
670         36                    stss   5 keyframes
706         2,024                 ctts   display offsets (B-frames)
2,770       1,220                 stsz   size of every frame
3,990       1,212                 stco   where each chunk starts
5,202       6,865         trak   track 2: audio
5,378       45                hdlr   media handler "soun"
5,535       186                   stsd   sample description "mp4a" (AAC-LC)
12,067      307           udta   title, artist, comment
12,374      8           wide   room for a 64-bit mdat size
12,382      1,187,889   mdat   the media: H.264 and AAC frames

100 00 00 14 66 74 79 70
Size and type
The first atom is 20 bytes (0x14) long and of type ftyp. As in MP4, the type sits at byte 4, so file-type detectors look there. A reader skips any atom it doesn't understand by jumping ahead by its size.
271 74 20 20 (qt )
The QuickTime brand
qt , with two spaces, is what marks this as a QuickTime movie rather than an MP4, whose brands are things like isom and mp41. Older MOVs have no ftyp at all and begin straight away with moov, mdat, free or wide, so detectors have to accept those too.
3moov
The movie atom: the index
Tracks, codecs, durations and tables that say where every frame is. A player can't show anything until it has read moov. Here it comes first because the file was written for the web; cameras and editors usually put it at the end, as in our ProRes sample.
4tkhd
The track header
Holds the display size and a transformation matrix. An iPhone filming in portrait stores landscape frames and a 90° rotation here, rather than turning the pixels.
5hdlr "vide" … hdlr "url "
Two handlers per track
A QuickTime detail MP4 dropped: each track has a media handler (vide, soun, tmcd for timecode) and a data handler for fetching the media. Here the data handler is url , and the data reference that follows says the media is in this same file.
6dinf
The data reference
In QuickTime, a track's media doesn't have to be in the same file. A reference movie points to media in other files; copy it to another computer without them and it plays nothing.
7stsd "avc1"
The sample description: which codec
Names the codec of each track. avc1 is H.264, hvc1 is HEVC, apcn, apch and apco are ProRes flavours, rle is the old Animation codec. This line decides whether a given player or browser can show the file.
8stts, stss, ctts, stsz, stco
The sample tables
Frame timing, which frames are keyframes, display offsets for B-frames, the size of every frame and where each chunk starts. Seeking is a lookup in these tables, exactly as in MP4.
9udta
User data: metadata
Title, artist and comment as ©nam, ©ART and ©cmt entries. iPhones also write keyed metadata such as com.apple.quicktime.location.ISO6709, the place where a video was recorded.
10wide
A placeholder
An 8-byte atom readers skip. If the media grows past 4 GB, the writer turns wide and the mdat header into one 64-bit size header, without moving anything else.
11mdat
The media data
1.2 MB of H.264 and AAC frames, interleaved, with no structure of their own. Without moov they can't be decoded.

Related formats

MOV vs MP4: what's actually different

	MOV (QuickTime)	MP4 (MPEG-4 Part 14)
Structure	Atoms: `ftyp`, `moov`, `mdat`…	The same design, standardised as the ISO base media file format
Brand in `ftyp`	`qt`	`isom`, `mp41`, `mp42` and others
Owner	Apple	ISO/IEC (an international standard)
Typical codecs	H.264, HEVC, ProRes, PCM, AAC, Animation, many legacy codecs	H.264, HEVC, AV1, AAC
Extras	Timecode tracks, reference movies, QuickTime-only metadata	Fragmented MP4 for streaming
Browser support	Safari; other browsers only unofficially, see below	Every current browser
Best for	Recording and editing on Apple devices, professional post-production	Sharing and the web

Because the structures match, a MOV that contains H.264 or HEVC video and AAC audio can be turned into an MP4 without re-encoding, which is called remuxing: ffmpeg -i input.mov -c copy -movflags +faststart output.mp4. It takes seconds and loses nothing. ProRes video and PCM audio aren't standard in MP4, so a ProRes MOV has to be re-encoded instead (for example to H.264 with -c:v libx264 -crf 20 -c:a aac).

Codecs

What's in your MOV: iPhone HEVC, H.264 and ProRes

The codecs you're most likely to find in a MOV file
Codec	Code in the file	Where it comes from	Plays in browsers?
H.264	`avc1`	iPhones set to Most Compatible, older Macs, screen recordings, exports	Usually, if the page or server labels it as MP4
HEVC (H.265)	`hvc1`	iPhones set to High Efficiency, the default setting	Safari; elsewhere only with a hardware decoder
Apple ProRes	`apco`, `apcs`, `apcn`, `apch`, `ap4h`, `ap4x`	Professional cameras, editing apps, iPhone Pro models in ProRes mode	Not in Chrome, Edge or Firefox
Animation	`rle`	Older motion-graphics work that needed transparency	No
AAC audio	`mp4a`	Almost all phone and consumer recordings	Yes
PCM audio	`lpcm`, `in24`, `twos`, `sowt`	Cameras and editing exports, usually alongside ProRes	Not in a MOV

iPhone video. Under Settings → Camera → Formats, High Efficiency records HEVC (since iOS 11, on iPhone 7 and later) and Most Compatible records H.264. Both are saved as MOV. HEVC was designed to need about half the bit rate of H.264 for similar quality, but a MOV that plays fine on the phone can show a black picture or nothing at all in Chrome or on an older PC. When you send a video by AirDrop, Messages or email, iOS may convert it to H.264 automatically if the receiving device can't handle HEVC. The video half of a Live Photo is a short MOV as well.

ProRes is Apple's family of editing codecs, introduced in 2007. Every frame is compressed on its own, which makes editing and scrubbing fast but files very large. At 1080p and 29.97 fps, Apple gives target data rates of about 45 Mbit/s for ProRes 422 Proxy, 147 Mbit/s for ProRes 422, 220 Mbit/s for 422 HQ and 330 Mbit/s for 4444; a minute of ProRes 422 HQ is over 1.5 GB. ProRes 4444 and 4444 XQ can carry an alpha channel (transparency). Our sample-prores-422-proxy.mov uses the smallest flavour and is still the largest file per second on this page.

Which codec is in my file?

On a Mac, open it in QuickTime Player and choose Window → Show Movie Inspector. Elsewhere, VLC shows it under Tools → Codec Information, and ffprobe file.mov (part of FFmpeg) lists every track.

On the web

Why some MOV files don't play in a browser

Safari plays MOV files natively. Chrome, Edge and Firefox don't officially support QuickTime: they answer "" (no) when a page asks canPlayType("video/quicktime"), so a <source type="video/quicktime"> is skipped before it is even downloaded. Because a MOV with H.264 and AAC is built like an MP4, it usually plays if the page labels it video/mp4 instead, and Chrome often plays one that is linked directly. What decides the rest is the codec:

H.264 + AAC: plays in practice almost everywhere, once the browser is willing to try. For a public page, remuxing to MP4 removes any doubt.
HEVC: Safari, and other browsers only on devices with a hardware HEVC decoder. Convert to H.264 for everyone else.
ProRes, Animation, PCM audio: editing formats. Browsers on Windows, Linux and Android can't decode them; export an H.264 MP4 for viewing.

Transparent video on the web

Safari can play HEVC with alpha in a MOV or MP4, which is how Apple devices show transparent video. Chrome, Edge and Firefox use VP9 with alpha in WebM instead, so sites that need transparency usually offer both.

Troubleshooting

Why won't my MOV play? Common problems and fixes

Symptom	Usual cause	Fix
Sound but black picture on Windows or in Chrome	HEVC video from an iPhone, and no HEVC decoder on that device.	Install Microsoft's HEVC Video Extensions on Windows, or re-encode: `ffmpeg -i in.mov -c:v libx264 -crf 20 -c:a aac out.mp4`.
Plays on the Mac, not in a web page	The page uses `type="video/quicktime"`, or the codec is ProRes or HEVC.	Remux H.264 files to MP4; re-encode the rest.
File is enormous	ProRes or another editing codec, or a screen recording at a high bit rate.	Export a viewing copy in H.264 or HEVC. Keep the ProRes original for editing.
Opens but shows nothing, or "media not found"	A reference movie whose media files didn't come along.	Copy the media files too, or export a self-contained movie from the editor.
Sideways video	The rotation is stored in the track header, and the app ignores it.	Use a player that respects it, or bake the rotation in by re-encoding.
Won't open after a crash or a dead battery	The recording stopped before `moov` was written at the end.	Repair tools can rebuild the index using a good file from the same device as a template.

How to

How to open, edit and convert a MOV file

macOS: QuickTime Player opens it, trims it (Edit → Trim) and exports it (File → Export As). iMovie and Final Cut Pro edit it.
Windows: the Media Player app plays MOV files with H.264 inside; HEVC needs the HEVC Video Extensions from the Microsoft Store. VLC plays nearly all MOVs, including ProRes. Apple's old QuickTime for Windows is unsupported and has known security holes, so don't install it.
Linux: VLC or mpv.
iPhone and Android: iPhones play their own MOVs in Photos. On Android, most gallery apps play H.264 MOVs, and VLC handles the rest.
Convert to MP4: remux with ffmpeg -i in.mov -c copy out.mp4 when the codecs are H.264 or HEVC plus AAC; otherwise re-encode, with FFmpeg or with HandBrake, a free app with ready-made presets.
Edit: DaVinci Resolve, Premiere Pro and Final Cut Pro all work with ProRes MOVs natively.

Renaming isn't converting

Renaming an H.264 .mov to .mp4 often works, because the structure is so similar, but the file still says qt inside and may carry QuickTime-only atoms. Remuxing with -c copy is just as fast and gives you a real MP4.

Security

Is a MOV file safe? Privacy and security

Location and device metadata. iPhone videos record where they were shot (com.apple.quicktime.location.ISO6709), the device model, software version and recording time. Check before you publish a video filmed at home: ffprobe lists the tags, and ffmpeg -i in.mov -map_metadata -1 -c copy out.mov removes them without re-encoding. Our sample-hevc.mov carries a made-up location so you can test exactly that.
Old QuickTime software. Apple stopped supporting QuickTime 7 for Windows in 2016 and it has unpatched vulnerabilities. Uninstall it if it's still on a PC.
Decoder bugs. A MOV can't run code by itself, but a crafted file could exploit a flaw in a video decoder. Keep your operating system and players updated.
Fake videos. A file named clip.mov.exe is a program. Turn on file name extensions in Windows File Explorer so you can see the real one.

Free downloads

Sample MOV files to download

Free sample MOV files for testing players, browsers, upload forms and transcoding pipelines. All are made from FFmpeg test patterns and generated tones, with the format written on screen. Each was checked with ffprobe and fully decoded without errors.

sample-720p-h264-aac.mov · 1.1 MBDownload Open

What's inside sample-720p-h264-aac.mov

A 10-second, 1280×720 QuickTime movie at 30 fps: H.264 High profile video and AAC stereo audio, with the index at the front. It's the kind of MOV that converts to MP4 without re-encoding.

The label
The bottom band names the resolution, frame rate, container and codecs, so you can see at a glance if a pipeline changed something.
Timecode and frame counter
Burned into the top of each frame. Skipped or repeated frames show up as jumps in the counter.
The flash and the beep
A white square flashes in the top right for 3 frames on every whole second, in step with a 1 kHz beep. If they drift apart, audio and video are out of sync.
Stereo test tones
440 Hz on the left channel and 660 Hz on the right, so swapped or mixed-down channels are easy to hear.
QuickTime brand
The ftyp atom says qt , so tools that check the brand see a real MOV, not an MP4 with a different extension.
Index first
moov starts at byte 20, before the media, so the file can start playing while it downloads.
Metadata
Title, artist and a comment naming this page, in the udta atom. Run ffprobe on it to see them.

All sample MOV files

720p H.264 + AAC
sample-720p-h264-aac.mov · 1.1 MB (1,200,271 bytes)
10 seconds at 1280×720, 30 fps. H.264 High profile with AAC-LC stereo at 128 kbps, brand qt , moov at the start.
- Checking a player, host or upload form accepts MOV
- Testing a MOV-to-MP4 remux step
Download Open
HEVC, iPhone-style
sample-hevc.mov · 152.9 KB (156,595 bytes)
4 seconds at 640×360, HEVC Main profile tagged hvc1 with AAC audio, and Apple-style metadata keys, including a made-up recording location (the Royal Observatory, Greenwich) and a creation date.
- Testing HEVC support in a browser or on a device
- Checking that an upload pipeline strips location metadata
Download Open
ProRes 422 Proxy + PCM + timecode
sample-prores-422-proxy.mov · 668.1 KB (684,156 bytes)
2 seconds at 320×180, 25 fps, in Apple ProRes 422 Proxy (apco), with 24-bit PCM mono audio and a timecode track starting at 01:00:00:00. Written like a camera file, with moov at the end. Most browsers can't play it.
- Testing editing and transcoding tools with ProRes input
- Checking how a site handles a MOV it can't preview
Download
Transparent video (Animation codec)
sample-animation-alpha.mov · 213.2 KB (218,276 bytes)
2 seconds at 320×180 in the QuickTime Animation codec (rle ) with an alpha channel: a moving box on a fully transparent background, plus a 50% transparent band. Lossless.
- Testing alpha support in editors and compositing tools
- Checking that a converter keeps (or deliberately drops) transparency
Download

Ways to test with them

Browser support: open sample-720p-h264-aac.mov and sample-hevc.mov in each browser you care about. Then try them in a page with type="video/quicktime" and with type="video/mp4" to see the difference the label makes.
Metadata stripping: upload sample-hevc.mov and download the result; ffprobe shouldn't find com.apple.quicktime.location.ISO6709 any more if your pipeline removes location data.
Unplayable input: sample-prores-422-proxy.mov is a valid MOV that most browsers can't decode. Use it to check thumbnails, error messages and fallbacks.
Transparency: convert sample-animation-alpha.mov with your tool of choice; the corners should stay fully transparent and the band half-transparent.
Sync: in the featured file, the white square and the beep should coincide on every second.

Free to use for testing, teaching and demos, commercially or not, with no attribution needed. A link back to this page is always appreciated.

Put it online

Have a MOV file? Give it a link.

Drop a MOV on 99helpers and it gets its own address that you can send instead of a large attachment. Visitors' browsers play it if they support its codec; for one link that plays everywhere, convert H.264 MOVs to MP4 first.

Put a MOV online

Questions

MOV files, frequently asked

What is a MOV file?

A video file in Apple's QuickTime format. It's a container that holds video, audio and sometimes timecode or caption tracks. iPhones and Macs create MOV files by default.

Is MOV the same as MP4?

Almost. MP4 was based on QuickTime, so the internal structure is the same, but MOV is Apple's format with its own brand and extras, and it can hold codecs such as ProRes that MP4 doesn't officially support. MP4 is the better choice for sharing.

How do I convert MOV to MP4?

If it holds H.264 or HEVC with AAC, remux it without quality loss: ffmpeg -i in.mov -c copy out.mp4. Otherwise re-encode with HandBrake or FFmpeg. On a Mac, QuickTime Player's File → Export As also makes a more compatible copy.

Why won't my iPhone video play on Windows?

It's probably HEVC. Install Microsoft's HEVC Video Extensions, use VLC, or set the iPhone to Settings → Camera → Formats → Most Compatible so it records H.264.

Can I play a MOV file in Chrome?

Often, if it contains H.264 and AAC. Chrome doesn't officially support QuickTime, so it ignores sources labelled video/quicktime, and it can't decode ProRes. Converting to MP4 is the reliable fix.

Why are MOV files so big?

Usually because of the codec. ProRes, used for editing, needs tens to hundreds of megabits per second. Screen recordings and high-frame-rate iPhone videos are large too. Re-encoding to H.264 or HEVC makes a much smaller viewing copy.

Can a MOV file have a transparent background?

Yes. ProRes 4444, HEVC with alpha and the older Animation codec can all store transparency in a MOV. On the web only Safari plays transparent MOVs; other browsers use WebM with VP9 alpha.

Does a MOV file contain my location?

Videos recorded on a phone often do, along with the device model and time. Remove it with ffmpeg -i in.mov -map_metadata -1 -c copy out.mov or a metadata tool before sharing publicly.

Related formats

Other file types explained

MP4 file WebM file MKV file AVI file HEIC file All file types

Keep going

Host a MOV file

Put a video online at its own address.

Share a MOV file

Send a video as a link instead of an attachment.

Host a presentation

Put slides and the videos they use online together.

Sources

Last reviewed 27 October 2026.