What Is AV1? How It Compares to H.265 and VP9

If you have looked at the codec stats in YouTube's "Stats for nerds", you have probably seen av01. That is AV1, the newest widely deployed video codec. It produces smaller files than H.264 and H.265 at the same quality, and nobody has to pay a license fee to use it. So why does almost every phone still record H.264 or H.265?

Where AV1 came from

AV1 was released in 2018 by the Alliance for Open Media, a group that includes Google, Netflix, Amazon, Microsoft, Apple, Meta, and major chip makers. It built on Google's VP9 and other research codecs. The main motivation was licensing: H.265 is covered by several patent pools with complicated fees, which held back its use on the web. AV1 is royalty-free.

How much smaller are AV1 files?

Results depend on the content and the encoder settings, but independent tests commonly find AV1 around 20 to 30% smaller than H.265 and around 50% smaller than H.264 at similar visual quality. The gains are largest at high resolutions and low bitrates, which is exactly what streaming services care about.

The catch: encoding speed

AV1's efficiency comes from searching through far more ways to describe each frame, and that search is expensive. Early encoders were hundreds of times slower than H.264. Modern encoders such as SVT-AV1 (from Intel and Netflix) are dramatically faster and usable on a desktop, but at good quality presets AV1 still takes noticeably longer than H.265 on the same CPU. Hardware AV1 encoders in recent GPUs close the gap for streaming and recording.

Where AV1 plays

• •Browsers: Chrome, Edge, and Firefox decode AV1 in software or hardware. Safari supports it on Apple devices with AV1 hardware, such as iPhone 15 Pro and later and Macs with M3 chips or newer.
• •Graphics cards: NVIDIA RTX 30 series and later, AMD Radeon RX 6000 and later, and Intel Arc decode AV1 in hardware.
• •Phones and TVs: many devices released since about 2021 decode AV1 in hardware. Older devices may play it in software with high battery or CPU use, or not at all.
• •Platforms: YouTube, Netflix, and many other services stream AV1 to devices that support it.

Should you compress your own videos to AV1?

It depends on where the file goes. For a personal archive played on recent devices, AV1 in MKV or MP4 saves real space. For files you send to other people, H.265 or H.264 is still the safer choice, because you cannot know what device will open them. For anything you upload to YouTube or social media, the codec you upload matters little, since the platform re-encodes it anyway.

Trying AV1 yourself with FFmpeg

ffmpeg -i input.mp4 -c:v libsvtav1 -preset 8 -crf 35 -c:a libopus -b:a 128k output.mkv

Lower preset numbers are slower and slightly more efficient; higher CRF values give smaller, softer files. Our CRF vs bitrate guide explains how CRF works.

Summary

AV1 is the most efficient widely supported codec today and it is royalty-free, which is why streaming giants adopted it first. For everyday sharing, its slower encoding and incomplete support on older devices keep H.265 and H.264 as the practical defaults for now.