Codec Compatibility Matrix

Compatibility table for containers (MP4 / MKV / MOV / WebM / AVI) and codecs (H.264 / H.265 / AV1 / VP9 / etc).

✓ Supported

△ Limited / Non-standard

✗ Not supported

Container	H.264	H.265	AV1	VP9	MPEG-4	ProRes	AAC	MP3	Opus
.mp4	✓	✓	✓	△	✓	△	✓	△	△
.mkv	✓	✓	✓	✓	✓	✓	✓	✓	✓
.mov	✓	✓	△	✗	✓	✓	✓	△	✗
.webm	✗	✗	✓	✓	✗	✗	✗	✗	✓
.avi	✓	△	✗	✗	✓	✗	△	✓	✗
.ts	✓	✓	✗	✗	✓	✗	✓	✓	✗
.flv	✓	✗	✗	✗	△	✗	✓	✓	✗

MP4 + VP9: Technically possible but non-standard; can cause browser compatibility issues
MP4 + ProRes: Playable on macOS but not recommended for general use
MP4 + MP3: Allowed by older specs but AAC is strongly preferred
MP4 + Opus: Relatively new support; some players do not support it yet
MOV + AV1: Supported on Apple Silicon and newer Apple devices; not on older hardware
AVI + H.265: Unofficial support only; works in VLC and some other players
MKV is the most flexible container and can hold virtually any codec combination

Popular uses

Diagnose playback incompatibilityChoose container and codec pairsCheck web delivery compatibility

Next tools

Video Format Converter Video Compressor Bitrate Calculator

What this tool does

Container × codec matrix
Browser / SNS / OS notes
When-to-use guidance

How to use

1
Pick the container you need
MP4 has the broadest support.
2
Check the codecs
See what works inside that container.
3
Re-mux if needed
Sometimes only the container needs to change — no re-encode required.

What each setting means

Container

MP4 / MKV / MOV / etc — the wrapper file.

Codec

H.264 / H.265 / AV1 — the compression scheme.

Recommended settings

Phone / SNS sharing

MP4 + H.264

Plays on virtually anything.

Web embed

WebM + VP9 / AV1

Transparency + high compression.

Editorial pipeline

MOV + ProRes / DNxHD

Edit-friendly mezzanine codecs.

Common pitfalls

Symptom: No audio after MP4 conversion

Cause: AC-3 / DTS / Vorbis isn't a standard MP4 audio codec.

Fix: Transcode audio to AAC.

Symptom: AV1 won't play

Cause: Older OS / browsers lack AV1 decode.

Fix: Fall back to H.264 / H.265.

Equivalent FFmpeg commands

Reference commands you can run on the desktop FFmpeg CLI.

Just change container

ffmpeg -i input.mkv -c copy output.mp4

Browser support & limits

Compatibility shown is a general reference; double-check for newest codecs and OS / browser combinations.

Privacy

This tool only does math in your browser. Inputs stay on your device — nothing is uploaded. Read the privacy policy →

Frequently asked questions

Fastest way to convert MKV → MP4?

If the codecs are H.264 + AAC, just remux with -c copy.

AV1 vs H.265?

AV1 is ~20% smaller at equivalent quality but has narrower hardware support today.