Video codec comparison
VP9 vs AV1
VP9 and AV1 are both royalty-free codecs from the same engineering tradition (Google-led, with AV1 being the Alliance for Open Media's successor to VP9). AV1 compresses about 30% better than VP9 at the same quality. The trade-offs: AV1 encoding is 5-10x slower than VP9, and hardware decode support is newer (most 2022+ devices but not older). YouTube serves both for the same video on modern browsers; the player picks based on your device's hardware capabilities.
Side-by-side
| Feature | VP9 | AV1 | Winner |
|---|---|---|---|
| Compression efficiency | Better than H.264 by ~30% | Better than VP9 by ~30% | AV1 |
| Encoding speed | Fast (~real-time) | Slow (5-10x VP9 time) | VP9 |
| Hardware decode | Universal (2017+) | 2022+ chips, expanding | VP9 |
| YouTube serves it | Yes (legacy default) | Yes (modern preference) | Tied |
| Licensing | Royalty-free | Royalty-free | Tied |
| Container | WebM | WebM / MP4 | AV1 |
| Software decoder availability | Universal | Universal in modern browsers | VP9 |
VP9 wins on
- Universal hardware decode on every modern phone / laptop since 2017.
- Fast encoding — ~5x faster than AV1 in software.
- Mature ecosystem — every YouTube video has had a VP9 variant since 2015.
- Predictable streaming behavior across all browsers.
AV1 wins on
- ~30% smaller files than VP9 at the same quality.
- Hardware decode in newest chips (iPhone 15+, RTX 4000+, Apple M3+).
- Future-proof: this is what YouTube is migrating to.
- Best compression of any royalty-free codec available today.
Verdict
For downloads: AV1 wins on file size, VP9 wins on encoding speed (matters for content you're re-encoding, doesn't for content you're just storing). For YouTube specifically, pick AV1 when available — the file is smaller and modern devices play it without issue. VP9 remains a solid fallback for older Android devices.