What you should know
H.264 is the safest general choice for browser and device support. H.265 can deliver similar quality at a smaller size but has uneven browser support, while AV1 is efficient and modern but can be slower to encode and unsupported on older devices.
When it is useful
Before uploading, define what the other person actually needs to do: watch the video, download it, verify information or keep it for longer.
- Choose H.264 when the recipient's hardware and browser are unknown.
- Choose H.265 for compatible devices and storage-sensitive workflows.
- Choose AV1 for modern web delivery when encoding time and device support have been tested.
Recommended process
A short, verifiable workflow reduces failures and avoids unnecessary re-uploads.
- Identify the devices and browsers that must play the file.
- Make a short test encode with the intended codec.
- Compare quality, size and playback CPU use.
- Keep an H.264 fallback when compatibility matters.
Practical checks
Compatibility depends on more than the filename extension. The codec, connection, browser and device also matter.
- The MP4 container does not guarantee that H.265 will play everywhere.
- Hardware decoding greatly affects battery use and smoothness.
- AV1 support is improving but old devices remain a concern.
Limits, privacy and responsibility
More efficient compression is not automatically better if the recipient cannot decode it. Encoding time can also outweigh file-size savings for quick transfers.
Frequently asked questions
Is H.265 always half the size of H.264?
No. Savings depend on content, settings and quality targets.
Can I put AV1 inside MP4?
Yes in some workflows, but player support still needs to be checked.