A Complete Guide to Video Formats: MP4, WebM, MOV, & AVI

Think of a container like a shipping box (e.g., .mp4, .mov). Inside that box, you have at least two things: the compressed video stream (a video codec like H.264) and the compressed audio stream (an audio codec like AAC).

The "format" is just the type of box. Its job is to hold everything together and tell the video player how the audio and video are synchronized. Some formats are universally accepted (like MP4), while others are specialized for specific jobs (like MOV for editing).

Here's a breakdown of the formats you need to know and when to use them.

1. MP4 (MPEG-4 Part 14)

Best For: Almost everything, especially web streaming and sharing.

Common Codecs: H.264 (most common), H.265 (HEVC), AV1 (video); AAC (audio).

MP4 is the undisputed king of video formats. It offers an excellent balance of high quality and small file size, thanks to efficient codecs like H.264. Its biggest strength is universal compatibility. An .mp4 file will play on virtually every browser, smartphone, smart TV, and operating system.

When to use it:

• Web Streaming: This is the #1 format for YouTube, Netflix, and embedding video on your website.
• Social Media: The recommended format for Instagram, X (Twitter), Facebook, and TikTok.
• Sharing: If you're sending a video to a friend or colleague, this is your safest bet.
• General Storage: It's a great all-around format for saving your videos.

2. WebM (Web Media)

Best For: A modern, open-source alternative to MP4 for web streaming.

Common Codecs: VP8, VP9, AV1 (video); Vorbis, Opus (audio).

WebM was developed by Google specifically for the web. It's built on open-source, royalty-free codecs, which is a big deal for browser and platform developers. It often provides better compression than MP4 (meaning smaller file sizes at the same quality), especially when using the VP9 or AV1 codecs.

It's now supported by all major browsers (Chrome, Firefox, Safari, Edge), making it a fantastic, high-performance choice for HTML5 video.

When to use it:

• HTML5 Web Video: Use it alongside an MP4 as a fallback to give modern browsers the smallest, fastest-loading file.

<video controls>
  <source src="video.webm" type="video/webm">
  <source src="video.mp4" type="video/mp4">
</video>

• Replacing GIFs: Animated WebM videos are a fraction of the size of old-school GIFs and look much better.

3. MOV (Apple QuickTime Format)

Best For: High-quality video editing, especially in the Apple ecosystem.

Common Codecs: ProRes, H.264 (video); PCM, AAC (audio).

The .mov format was created by Apple for its QuickTime player. Its power lies in its ability to store extremely high-quality, often "visually lossless" video tracks, like those from the Apple ProRes codec. This makes it a favorite in professional video production and editing.

While MOV files (especially those using H.264) will play on many devices, they are not ideal for web streaming due to their potential for massive file sizes.

When to use it:

• Video Editing: This is the standard format for editing in software like Final Cut Pro. Adobe Premiere Pro also handles it perfectly.
• Master Files: When you export your "final" high-resolution master copy from your editing software, MOV (ProRes) is a perfect choice for archiving.
• Apple Ecosystem: It's the native format for recording video on iPhones and Macs.

4. AVI (Audio Video Interleave)

Best For: Legacy use and some Windows-based archiving.

Common Codecs: DivX, XviD, MJPEG (and many other older codecs).

AVI is a legacy format. Developed by Microsoft in 1992, it was one of the first popular video formats. Its main issue is that it's an older, less efficient "box." It doesn't support modern codecs as well as MP4, can result in huge file sizes, and has very poor support for web streaming.

Today, there are very few reasons to choose AVI for a new project. Its main use is for playing or archiving older video files from that era.

When to use it:

• Legacy Systems: If you're working with very old hardware or software that specifically requires .avi files.
• Playing Old Files: You may have old home movies or downloads in this format. Modern players like VLC can still handle them.
• Avoid for all modern uses (web, sharing, editing).

Quick Comparison: At-a-Glance