Which Video Format Is Actually Smallest? H.264 vs VP9 vs AV1, Measured
"Convert it to MP4 to save space" is advice you hear constantly, and it's mostly wrong. MP4 is a container — a box that holds video, audio and metadata — not a compression method. The thing that actually decides the file size is the codec inside it: H.264, VP9 or AV1. Rename a .webm to .mp4 and you've changed nothing about how big it is. So we measured how much the codec really matters. How we…
The size of video files is determined by codecs rather than containers such as MP4. To compare the codecs H.264, VP9 and AV1, two standard 720p test clips were encoded in each format. Perceptual quality was measured using VMAF, a Netflix metric, allowing for equal perceived quality comparison of file sizes. At a VMAF 90 target, VP9 is about 40% smaller than H.264, while AV1 is roughly 60% smaller than H.264.
The same 10-second clip results in 3.3 MB for H.264, 2.0 MB for VP9, and 1.3 MB for AV1. However, newer codecs come with a CPU cost, making AV1 and VP9 encode times significantly longer than H.264. The choice between codecs depends on the balance between encoding time and bandwidth savings over multiple views. The study was conducted using FFmpeg quality sweeps and VMAF scoring, with the implementation script running entirely in a browser using ffmpeg.wasm.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
