AV1 vs H.264
In this test, AV1 at 500 kbps (VMAF 88.93) beats H.264 at double the bitrate (VMAF 81.26). That is what fifteen years of codec research buys: the same quality for half the bill.
Bitrate target
Both codecs get the identical budget; the slider shows what each does with it. 500 kbps for 720p is deliberately starved.
H.264
x264 · 2003
1,174 KB encoded
AV1
SVT-AV1 · 2018
1,088 KB encoded · 86 KB smaller
VMAF scores perceived quality 0–100 against the pristine source; above about 93 is generally indistinguishable from the original.
Quality per kilobit
VMAF against the encode's actual achieved bitrate. H.265 is measured but not shown in the player: browser HEVC playback depends on hardware, so a visual demo would silently fail for many readers.
View as table
| Encode | Actual kbps | VMAF |
|---|---|---|
| H.264 (x264) @ 500k | 451 | 64.54 |
| H.264 (x264) @ 1000k | 939 | 81.26 |
| H.264 (x264) @ 2500k | 2,382 | 91.15 |
| H.265 (x265) @ 500k | 498 | 76.73 |
| H.265 (x265) @ 1000k | 985 | 86.63 |
| H.265 (x265) @ 2500k | 2,449 | 93.16 |
| AV1 (SVT-AV1) @ 500k | 464 | 88.93 |
| AV1 (SVT-AV1) @ 1000k | 870 | 93.22 |
| AV1 (SVT-AV1) @ 2500k | 2,072 | 96.16 |
Methodology
The source is a 10-second, 1080p30 excerpt of Big Buck Bunny (© Blender Foundation, CC-BY 3.0), scaled once to a near-lossless 720p reference. Each codec then encodes that reference at 500, 1000 and 2500 kbps: x264 and x265 at preset medium with a 1.5× rate cap, SVT-AV1 at preset 6 in plain ABR, all 4:2:0, using FFmpeg 8.1. VMAF is computed against the same reference, and the chart plots each encode's actual achieved bitrate rather than the nominal target.
Fair-fight caveats: one short animated clip is not a corpus; animation compresses differently than camera footage (and tends to flatter modern codecs). Encoder presets matter enormously, and the source itself is a high-bitrate H.264 master, not a pristine original. Treat this page as an honest demonstration of the shape of the gap, not a benchmark to cite in a codec war.
Why not show H.265 in the player?
Chrome and Firefox only decode HEVC when the operating system or GPU provides a licensed decoder, so an HEVC demo would silently show nothing for a large share of readers. It is measured in the chart, where no playback is required; the licensing story behind that gap is its own lesson in why AV1 exists.