Convexy

How to convert HEIC to AVIF on iPhone

These two formats are close relatives: both are a single video frame wrapped in a HEIF-style container. The difference that decides everything is not compression — it is patent licensing.

The same idea, two codecs

HEIC is an image encoded with HEVC (H.265) in a HEIF container. Apple made it the iPhone camera default in iOS 11.

AVIF is an image encoded with AV1 in a HEIF-style container. AV1 comes from the Alliance for Open Media — Google, Mozilla, Netflix, Amazon, Apple and others — and was designed from the outset to be royalty-free.

Architecturally they are the same trick: take a modern video codec, encode a single intra-frame with it, and put it in a container. Both are far more efficient than JPG. Both support transparency, HDR and 10-bit colour.

The split is legal. HEVC is patent-encumbered, with licensing costs that browser vendors would not accept — so no mainstream browser will render a HEIC. AV1 has no such burden, so browsers adopted AVIF and the web has been moving to it steadily. That is the whole story, and it is why this conversion exists.

When to do it

When not to: if the photo is staying on your iPhone, HEIC is already excellent and converting achieves nothing but a lossy re-encode. And if the destination is an older system, AVIF may be too new — that is what JPG is for.

This is a lossy-to-lossy re-encode. Your camera already compressed the image once with HEVC. Converting decodes it and compresses it again with AV1. AVIF is an efficient codec, so at a sensible quality setting the second generation is hard to see — but it is a second generation, and the loss is cumulative. If the shot also exists as a ProRAW DNG, encode AVIF from that instead: one lossy generation always beats two.

Will the file get smaller?

Maybe, maybe not — and anyone who promises you a definite answer is guessing. HEVC and AV1 are close in efficiency, with AV1 usually a little ahead on stills. But you are re-encoding an image that has already been through one lossy codec, and the quality setting you pick matters more than the codec difference does. Expect the AVIF to land in the same broad neighbourhood as the HEIC. Some images shrink; some grow slightly.

Convert to AVIF for compatibility with the web and for the best codec available at the destination — not on the assumption of a guaranteed size win over HEIC.

AVIF or WebP for the web? AVIF compresses better. WebP has broader support in older software outside the browser. If your audience is on current browsers, AVIF is the better file. If you need one format that will not surprise anyone, WebP is the safer bet. Convexy writes both — WebP through the bundled libwebp, since Apple's frameworks have no WebP encoder at all.

What does not survive

Live Photo motion and depth maps are HEIC-specific extras with no equivalent in the AVIF you get out — you are converting the still image, not the bundle around it. Metadata (EXIF, GPS, IPTC) is stripped by default, which is the correct default for an image you are about to publish: intact EXIF in a web-published photo can reveal exactly where it was taken. Turn the toggle off in Options if you specifically need the tags kept.

The whole conversion runs on your device with Apple's imaging frameworks — no upload, no account, no server.

How to do it

  1. Pick the HEIC

    Tap Browse files or choose from Photos. Select several at once to convert a set of images as a batch — useful when preparing a gallery for a site.

  2. Choose AVIF

    AVIF appears among the formats a HEIC can become. Tap it.

  3. Set the quality

    AVIF holds up well at aggressive settings, which is its main advantage. Do not push it to the floor on an image that has already been through one lossy encode.

  4. Resize if this is for the web

    An iPhone photo is far bigger than any web layout needs. Capping the maximum dimension in Options saves more bytes than any codec choice can.

  5. Convert, then save or share

    Compare the sizes on the result screen, then save to Files or push the image straight into your publishing tool.

Common questions

What's the difference between HEIC and AVIF?

They use the same architecture — a single video frame in a HEIF-style container — but different codecs. HEIC uses HEVC (H.265), which is patent-encumbered, so no browser will display it. AVIF uses AV1, which is royalty-free, so browsers support it. The compression is broadly comparable, with AV1 usually a little ahead on still images. Licensing, not technology, is what separates them in practice.

Will the AVIF be smaller than the HEIC?

Possibly, but do not count on it. The two codecs are close in efficiency, and you are re-encoding an image that has already been compressed once. The quality setting you choose affects the result more than the codec difference does. Convert to AVIF because you need a format browsers can actually display — not for a guaranteed size reduction.

Can browsers display AVIF?

Yes — every current mainstream browser supports it, which is the entire point of the format. This is the decisive practical difference from HEIC, which no browser will render because of HEVC's patent licensing. Support outside browsers is patchier: some older desktop software and upload forms still do not handle AVIF.

Does converting HEIC to AVIF lose quality?

Yes, technically. Both are lossy codecs, so the image is decoded and re-compressed — a second lossy generation on top of the camera's original encode. AVIF is efficient enough that at a reasonable quality setting the difference is invisible. As always, if you have a less-compressed original (a ProRAW DNG, for instance), encode from that instead of from the HEIC.

Should I use AVIF or WebP on my website?

AVIF compresses noticeably better and supports HDR properly, so it produces the smaller, better file. WebP has been around longer and is supported by more non-browser software, so it is less likely to surprise anyone. Many sites serve AVIF with a WebP or JPG fallback. Convexy can write all three.