With so many video formats available — MP4, MKV, MOV, WebM, AVI, and more — it can be hard to know which one to use. The truth is, there's no single "best" format. The right choice depends on what you're doing with the video.
Understanding Video Containers vs. Codecs
First, an important distinction:
- Container (format) — the file wrapper: MP4, MKV, MOV, WebM, AVI
- Codec — the compression algorithm inside: H.264, H.265, AV1, VP9
A container can hold different codecs. For example, an MP4 file can contain H.264, H.265, or even AV1 video. The container determines compatibility; the codec determines quality and file size.
MP4 (.mp4)
Best for: Universal sharing, social media, web
MP4 is the most widely supported video format in the world. It plays on every device, browser, and platform without any additional software.
✅ Use MP4 when:
- Sharing on social media (YouTube, Instagram, Facebook, Twitter)
- Sending via email or messaging apps
- Embedding video on a website
- Compatibility is the top priority
❌ Avoid MP4 when:
- You need multiple audio tracks or subtitle streams
- You're archiving with maximum flexibility
MKV (.mkv)
Best for: Home media servers, archiving, multiple tracks
MKV (Matroska) is a flexible container that supports virtually unlimited video, audio, and subtitle tracks. It's the preferred format for Plex, Jellyfin, and Kodi.
✅ Use MKV when:
- Running a home media server
- Archiving movies or TV shows with multiple language tracks
- Storing videos with embedded subtitles
- You want maximum flexibility
❌ Avoid MKV when:
- Sharing with people who may not have a compatible player
- Uploading to social media (most platforms don't accept MKV)
MOV (.mov)
Best for: Apple ecosystem, professional editing
MOV is Apple's native video format, used by iPhones, iPads, and Final Cut Pro. It's essentially Apple's version of MP4 — very similar under the hood.
✅ Use MOV when:
- Working within the Apple ecosystem
- Editing in Final Cut Pro
- Your source footage is from an iPhone
❌ Avoid MOV when:
- Sharing with Windows users who don't have QuickTime
- Uploading to platforms that prefer MP4
WebM (.webm)
Best for: Web video, open-source projects
WebM is Google's open-source container format, designed specifically for web use. It typically contains VP9 or AV1 video with Opus audio.
✅ Use WebM when:
- Embedding video on a website with the
tag - You want a royalty-free format
- Targeting modern browsers
❌ Avoid WebM when:
- Compatibility with older devices or software is needed
- Sharing outside of web contexts
AVI (.avi)
Best for: Legacy compatibility only
AVI is an old Microsoft format from 1992. While it's still widely recognized, it's inefficient and lacks modern features. There's rarely a reason to use AVI for new content.
✅ Use AVI when:
- Working with very old software that only accepts AVI
- Converting legacy AVI files to modern formats
❌ Avoid AVI when:
- Creating new content (use MP4 instead)
- File size matters
Quick Reference Guide
| Use case | Recommended format |
|---|---|
| YouTube upload | MP4 (H.264) |
| Instagram / TikTok | MP4 (H.264) |
| Home media server | MKV (H.265) |
| iPhone footage | MOV or MP4 |
| Website embed | WebM (AV1) or MP4 |
| Email attachment | MP4 (H.264, compressed) |
| Long-term archive | MKV (H.265) |
| Editing project | MOV or MKV |
Converting Between Formats
FinalConvert supports all major video formats. Click the Format button to select your output container and codec, then click Convert.