MP4 and WebM are containers: they hold video, audio, subtitles, and technical metadata. Quality and compatibility depend not only on the extension but also on the codecs inside the file.
What each container commonly holds
- MP4 often contains H.264 or H.265 video with AAC audio.
- WebM commonly uses VP9 or AV1 video with Opus audio.
The same resolution does not guarantee the same file size. A newer codec may compress better, but take longer to process and fail on older devices.
When to choose MP4
MP4 with H.264 and AAC remains the most predictable option when a file must open across phones, computers, televisions, and editing software. It is usually the safer choice when you cannot check the recipient’s device.
When to choose WebM
WebM is useful when a smaller file at comparable visual quality matters and recipients have modern VP9 or AV1 support. Some editors and older media players handle WebM less reliably than MP4.
Why video and audio may be separate
YouTube can store higher resolutions as video-only streams. Audio arrives separately, and a complete file is created by combining both streams. This is why a 1080p or higher option can take longer to prepare than a smaller version.
Send as media or as a file
When sent as regular media, Telegram may prepare the video for convenient playback. Send it as a document when preserving the received file without another conversion matters. The recipient still needs software that supports its codecs.
A practical choice
- Maximum compatibility: MP4 with H.264/AAC.
- Smaller file and modern devices: WebM with VP9/Opus.
- Editing: use the original master whenever possible instead of a recompressed copy.
- Unsure: start with MP4.
For vertical clips, apply the same rules and also check the YouTube Shorts guide.