HEVC vs AV1: Equal-Quality Bitrate Test
At approximate matched SSIM 0.992, AV1 used 3,402.6 kbps and HEVC used 3,758.5 kbps on the same animated excerpt. AV1 was about 9.5% smaller in this run. That does not establish a universal codec ranking, and HEVC may still be the usable choice where a device or upload surface documents HEVC but not AV1.
Short answer
AV1 was about 9.5% smaller than HEVC at matched SSIM 0.992 on our test clip, 3,402.6 kbps against 3,758.5 kbps. HEVC can still be the usable choice where a device or upload surface documents HEVC but not AV1.
Measured data
The video run used a 10 second, 1920 x 1080, 30 fps excerpt of Big Buck Bunny, an animated film rather than camera footage, licensed CC BY 3.0 by the Blender Foundation. Results describe this clip and these encoder settings, not every video or any platform pipeline.
| Codec and encoder | Measured SSIM | Interpolated bitrate | CRF rungs |
|---|---|---|---|
| HEVC, libx265 medium | 0.992 | 3,758.5 kbps | 18 and 24 |
| AV1, libsvtav1 preset 8 | 0.992 | 3,402.6 kbps | 18 and 24 |
The equal-quality figures are approximate linear interpolation between the two bracketing points from each measured curve.
Arithmetic: (1 - 3,402.6 / 3,758.5) x 100 = 9.5% smaller for AV1 on this run.
When to use each option
Use HEVC for a documented HEVC workflow
HEVC is useful when capture, editing, playback and the exact upload surface all name it. Do not infer acceptance from MOV or MP4 alone.
Use AV1 for an explicit AV1 path
The local result favored AV1, but decode coverage and upload support still decide whether the file is usable.
Use neither as an interchange default
If recipients or platforms are unknown, a verified H.264 export is usually the lower-risk handoff.
Questions people ask
Is AV1 always better than HEVC?
No. It was smaller at matched SSIM in this encoder run. Other content, presets and implementations can change the result.
Why is this not an equal-file-size test?
This page fixes measured quality and compares bitrate. Fixing size and comparing quality is a different experiment.
Can HEVC and AV1 be inside MP4?
Both can be carried by MP4, but that does not mean a destination accepts both codecs.
What footage was measured?
A 10 second Big Buck Bunny excerpt, which is animation rather than camera footage, under CC BY 3.0.
Measured vs sourced
Cells marked measured are Koldflux Media Lab measurements. Cells marked sourced derive from each platform / codec standards body. Cells marked guidance are expert guidance, not measured.
Sources
- FFmpeg codec documentation (read 2026-10-08)
- Alliance for Open Media: AV1 features (read 2026-10-08)
- Blender Foundation: Big Buck Bunny and CC BY 3.0 (read 2026-10-08)
Verified at 2026-10-08.
Next steps
Inspect my file: /tools/validate
Convert / make correct version: /tools/convert
Create all target versions: /tools/pack