What is an MP4 file?
MP4 stands for MPEG-4 Part 14 video. It was created by the Moving Picture Experts Group and first released in 2001. MP4 is the most widely supported video format, and H.264 video with AAC audio inside it plays on essentially every device made in the last fifteen years.
| Type | video |
|---|---|
| Compression | Lossy |
| Usually contains | H.264 or H.265 video with AAC audio |
| In a browser | plays in every browser, phone and smart TV |
| Common uses | phone videos, YouTube uploads, social media and streaming |
| MIME type | video/mp4 |
Which format should you convert MP4 to?
- MP4 to MOV to edit in iMovie or Final Cut Pro on a Mac.
- MP4 to MP3 to keep only the soundtrack, for music or a podcast.
- MP4 to GIF to share a short silent clip that loops anywhere.
- MP4 to WebM to embed on a web page with a small file size.
MP4 is already lossy, so converting it to a lossless format makes the file bigger without improving it; pick a lossless target only if a program requires one.
How to open an MP4 file
Whether an MP4 file opens with a double click depends on the device. Here is what works on each, without buying software:
| Windows | Films and TV and Media Player open the common formats; VLC opens almost any video file, MP4 included. |
|---|---|
| Mac | QuickTime Player opens formats Apple supports; VLC or IINA open the rest. |
| iPhone and iPad | The Files app plays formats Apple supports. For others, a player such as VLC for iOS, or converting the file here, is the easiest route. |
| Android | Most gallery and music apps play the common formats; VLC for Android plays almost everything. |
| Web browser | MP4 plays in every browser, phone and smart TV. |
Want the technical details? See what a .mp4 file is, with its MIME type, file signature and a viewer.
MP4 compared with other video formats
How MP4 stacks up against the formats people most often convert it to or from:
| Format | Compression | Usually contains | Released | Best for |
|---|---|---|---|---|
| MP4 | Lossy | H.264 or H.265 video with AAC audio | 2001 | phone videos, YouTube uploads, social media and streaming |
| MOV | Lossy | H.264, HEVC or ProRes video with AAC audio | 1991 | iPhone recordings, Final Cut Pro and screen recordings on Mac |
| MKV | Lossy | almost any codec, often H.264 or H.265 with several audio and subtitle tracks | 2002 | films and TV rips, OBS recordings and anime releases |
| WebM | Lossy | VP8, VP9 or AV1 video with Vorbis or Opus audio | 2010 | web video, screen recorders and browser-based recordings |
| AVI | Lossy | MPEG-4 Part 2 (Xvid, DivX), MJPEG or uncompressed video with MP3 or PCM audio | 1992 | older camcorders, digital cameras and legacy video libraries |
How to use the MP4 converter
- Choose the format you want in the Convert to menu.
- Drop your MP4 files on the box, or press Choose MP4 files. Several files can go in at once.
- Adjust the settings if you need to; the defaults suit most people.
- Press Convert and save each file with its Download button. Nothing is uploaded at any point.
Tips for converting MP4 files without losing quality
MP4 is lossy, so some detail was already discarded when the file was made. Converting it cannot bring that back. Converting to a lossless format preserves what is left exactly but makes the file larger; converting to another lossy format adds a small extra loss, which is invisible at sensible settings.
- Keep the original recording. Every re-encode costs a little detail, so convert from the best copy you have, not from a file that was already converted.
- Know whether you need a new container or a new codec. MOV, MKV and MP4 can all hold H.264 video, and switching between them is fast and lossless; changing the codec means re-encoding, which is slower.
- For sharing, MP4 with H.264 at 1080p or 720p is the safe choice: every phone, browser and social network plays it.
- Phones record at very high bitrates. If a file is too big to send, lowering the resolution to 720p usually shrinks it far more than any quality setting.
Convert MP4 files from the command line
Everything this page does can also be done in a terminal. The most common MP4 conversion, to MP3, looks like this with ffmpeg:
ffmpeg -i input.mp4 -vn -c:a libmp3lame -b:a 192k output.mp3Change the output extension to pick another format. The converter above runs the same ffmpeg engine inside your browser, so you get the result without installing anything.
MP4 converter FAQ
What is an MP4 file?
MP4 stands for MPEG-4 Part 14 video, a video format created by the Moving Picture Experts Group in 2001. MP4 is the most widely supported video format, and H.264 video with AAC audio inside it plays on essentially every device made in the last fifteen years.
How do I open an MP4 file?
MP4 plays in every browser, phone and smart TV. If the program you need will not open it, convert it to a more widely supported format above.
What is the most common MP4 conversion?
MP4 to MP3 is the conversion people search for most. MP3 holds sound only, so the picture is discarded and the soundtrack is encoded as MP3 at 192 kbps.
Does converting MP4 files here upload them?
No. Every conversion on this page runs inside your browser, so your MP4 files never leave your device.
Is the MP4 converter free?
Yes. There is no sign-up and no watermark, and no limit on how many MP4 files you convert. The site is supported by advertising.
Can I convert MP4 files on iPhone or Android?
Yes. Open this page in Safari on iPhone and iPad, or in Chrome on Android, choose your MP4 files and download the results to your Downloads folder.
Can I convert several MP4 files at once?
Yes. Drop as many as you like; they are converted one after another, each with its own download button.