If you need one video format that plays everywhere, the answer is MP4 with H.264 video and AAC audio. It is the most universally compatible video format in existence.
Why MP4/H.264 is universal
H.264 (also called AVC) was standardized in 2003. Over the next decade, hardware H.264 decoders were built into every smartphone, tablet, smart TV, game console, and computer processor. Every web browser supports H.264 natively. Every major operating system includes H.264 decoders.
This ubiquity means an MP4/H.264 file created today will play on: - Any iPhone or iPad (all models) - Any Android phone (Android 3.0+, which is every device in use) - Windows (7, 8, 10, 11) - macOS (all versions) - Linux (with codecs installed, which most distributions include) - Chrome, Firefox, Safari, Edge (all versions) - Smart TVs (Samsung, LG, Sony, etc.) - Game consoles (PlayStation, Xbox, Nintendo Switch) - Car infotainment systems
No other video format has this level of support.
Format compatibility comparison
MP4/H.264: Plays everywhere. Moderate compression efficiency.
MP4/H.265 (HEVC): Plays on most modern devices (2017+). Better compression (40-50% smaller files at the same quality). Some older devices and browsers lack support. Safari supports it. Chrome added support in 2022.
WEBM/VP9: Plays in Chrome, Firefox, Edge. Limited support in Safari. Not supported on most smart TVs. Excellent compression.
WEBM/AV1: Plays in newest browsers and devices. Limited hardware decoder support. Best compression of any format. Not yet universal.
MKV: Open container format. Plays on computers and many smart TVs. Not supported in browsers or iOS. Flexible (supports almost any codec).
AVI: Legacy format from 1992. Large files. Limited codec support in the container. Mostly obsolete but still sometimes encountered.
When to use something other than MP4/H.264
H.265: When file size matters more than compatibility. Ideal for personal archives, where you control the playback devices.
VP9/AV1: For web delivery where you can serve format-specific versions (WEBM for Chrome/Firefox, MP4 for Safari). YouTube internally uses VP9 and AV1 for streaming.
MKV: For personal media libraries managed by software like Plex, Kodi, or VLC. MKV supports subtitle tracks, multiple audio tracks, and chapter markers better than MP4.
ProRes: For professional video editing. High quality, fast encoding/decoding, designed for editing workflows rather than delivery.
When universal playback across every device, browser, and platform is the priority, the MediaBrew format conversion tool converts source files directly to standard MP4 with H.264 and AAC.