Add Subtitles to a MOV Video

Where your MOV probably came from

MOV is Apple's QuickTime format, and MP4 was developed from it, so the two share most of their internal structure. What varies from file to file is the codec inside, and that tends to follow the device that made it:

iPhone and iPad camera

HEVC when the camera is set to High Efficiency, H.264 under Most Compatible, with AAC sound. Recent models often record HDR.

Mac screen recordings

Made with the Screenshot toolbar or QuickTime Player, normally H.264 with AAC at the display's full resolution.

Mirrorless and compact cameras

Many save MOV with H.264 or HEVC, and some record uncompressed PCM sound instead of AAC.

Final Cut Pro, Premiere Pro or DaVinci Resolve exports

Either H.264 or HEVC files meant for delivery, or ProRes masters meant for further editing.

Not sure which you have? On a Mac, Finder's Get Info window lists the codecs under More Info. In the editor, the "Ready to render" summary names the sound format and the codec the subtitled copy will use.

What decodes in which browser

The editor reads the MOV in the page and hands the picture to your browser's built-in decoder, so the codec decides whether a file can be rendered:

• H.264 MOVs render in every supported browser.
• HEVC MOVs render in Safari on a Mac as a rule, and in Chrome or Edge when the computer's hardware and operating system can decode HEVC. Elsewhere the editor reports that it can't decode HEVC video.
• ProRes isn't among the codecs browsers decode, so a ProRes MOV gets a can't-decode message too. Export an H.264 or HEVC version from your editing app, or convert it with HandBrake, and subtitle that copy.
• Other editing codecs such as DNxHR, CineForm or uncompressed video are refused in the same way.

iPhone clips have their own quirks, from HDR to getting the file off the phone, and subtitling iPhone video deals with them. H.264 versus H.265 explains why Apple moved its cameras to HEVC.

Subtitling a MOV in five steps

1. Copy the MOV to your computer with AirDrop, Image Capture, a cable or a card reader, and open the editor in Safari, Chrome, Edge or Firefox.
2. Choose the file. If the bar above the preview shows its dimensions, the MOV was read; "Can't render this file" means the codec is the obstacle, as described above.
3. Get the lines in: AI subtitles, Import SRT / VTT, or typing with Enter at the playhead.
4. Correct and style them, keeping clear of anything the camera or the app placed in the lower part of the frame.
5. Click Render video, confirm the summary, and download the MP4 when it's ready.

Why you get an MP4 back

The editor writes MP4 and nothing else. For an H.264 or HEVC MOV that changes very little in practice: QuickTime Player, Photos, iMovie, Final Cut Pro and the major upload pages all accept MP4, and the picture inside is the same kind of stream a MOV would carry. The new file is named after your original with -subtitled.mp4 on the end, so the MOV stays untouched beside it.

If a later step in your workflow insists on a .mov extension, the streams can be moved into a MOV without another encode: ffmpeg -i clip-subtitled.mp4 -c copy clip-subtitled.mov rewraps the picture and sound. MP4 versus MOV covers the small practical differences between the two containers.

Camera sound, HDR and other MOV quirks

• Uncompressed PCM audio, common in camera MOVs, is copied into the MP4 as it is, because MP4 can store it. The file stays larger than it would with AAC, and some players and phones are less comfortable with PCM inside an MP4. If one plays the picture in silence, convert only the sound: ffmpeg -i clip-subtitled.mp4 -c:v copy -c:a aac clip-aac.mp4. When an exported video has no sound lists other causes.
• HDR footage, including Dolby Vision and HLG clips from iPhones, is rendered in standard dynamic range. The summary warns you first, and colours can look a little different from the original on an HDR screen.
• Log footage, the flat-looking profile many cameras offer for grading, is treated as ordinary video. Grade it in your editor before subtitling, because the text is burned onto whatever picture you give the editor.
• A MOV shot in portrait with a rotation flag renders upright, at the shape you see when it plays.
• Long full-resolution recordings make big files. Where the browser allows it, the render streams to its storage on your disk, so check free space before you start; large video files has more on limits.

Three MOV jobs

If you only need the words

To get a transcript rather than subtitles from a MOV, MOV to text works on the file directly, and the AI subtitle generator produces an SRT or VTT without rendering a video. Doing everything on a Mac? Adding subtitles on a Mac compares iMovie, Final Cut Pro and this browser route.

About the subtitle editor on this page

Opens

MP4, MOV, M4V, WebM, MKV videos your browser can decode

Subtitles from

AI (from the speech, optionally translated into one of 21 languages), an SRT or VTT file, or typing them in

You download

An MP4 with the subtitles drawn into the picture at the original resolution and frame rate, plus SRT and VTT files

Cost

Editing, styling, rendering and SRT/VTT export are free, with no account and no watermark. AI subtitles cost 1 credit per minute (5-credit minimum per video); signing in with Google gives 100 free credits and accounts get 10 free credits a day

Privacy

The video never leaves your device and is rendered in your browser. Only for AI subtitles is the audio sent, over HTTPS, and it is deleted within 30 minutes of delivery

Rendering needs

Chrome or Edge 94+, Safari 16.4+, or Firefox 130+ on a computer. Editing and SRT/VTT export work in any current browser