HEIC to AVIF
An iPhone file opens right in the tab and saves as AVIF. Nothing is uploaded anywhere, and portrait shots do not come out sideways. On our corpus a 1200×800 frame in AVIF averages 45 kB for a photograph and 1 kB for flat graphics — 40% of what JPEG takes at the same quality.
How to do it
- Pick a HEIC file, drag it in, or paste with Ctrl+V
- The format is already set to AVIF — adjust the quality if you like
- Take the finished file. Several at once works too — you get a ZIP
Frequently asked questions
- How much smaller will the file be?
- On our corpus a 1200×800 frame in AVIF averages 45 kB for a photograph and 1 kB for flat graphics — 40% of what JPEG takes at the same quality.
- How visible is the loss?
- On flat graphics at quality 80, AVIF reaches a peak channel deviation of 112 with 0.43% of pixels visibly off. On a photograph that is imperceptible; on a diagram or screenshot with hard edges it shows, and PNG is the safer choice there.
- Why does HEIC need converting at all?
- The iPhone shoots HEIC because it compresses about twice as well as JPEG. Half the software out there will not open it. Here it is decoded inside your tab by libheif — the file is never sent anywhere. We cannot write HEIC: libheif only reads.
- Why do phone photos sometimes come out sideways?
- Because the orientation lives in a separate EXIF tag rather than in the pixels, and most converters ignore it. Here the tag is read and applied before anything else, so a portrait shot stays portrait.