AVIF: HDR, Deep Color, Transparency and Browser Support

HDR: what it is and why a picture needs it

HDR (High Dynamic Range) is an image's ability to store a far wider spread of brightness than an ordinary SDR photo. In a regular picture the brightest pixel is simply "white." In HDR, a white sky, a glint on metal and a candle flame can differ in brightness by tens of times, just like in real life.

JPEG can't do this at all — it's designed for the standard range. AVIF, by contrast, was built around video technology, where HDR has long been the norm, and it inherits that capability. On an HDR display an AVIF photo looks three-dimensional: the sun truly dazzles, and the deep shadows keep details that JPEG would simply crush to black.

PQ and HLG: two roads to HDR

HDR in AVIF is implemented through so-called transfer curves from the Rec. 2100 standard. There are two, and each serves a purpose:

• PQ (Perceptual Quantizer) — an absolute curve: it specifies a precise brightness in nits (up to 1000 nits and beyond). Used in HDR10 and Dolby Vision, ideal for film and studio content.
• HLG (Hybrid Log-Gamma) — a hybrid curve, backward-compatible with SDR screens. Designed for broadcast: one signal looks decent on both an old and a new TV.

For the user the difference is small — both deliver "real HDR." What matters is that AVIF understands both curves, so it suits studio photography and smartphone content alike.

Deep color: 10 and 12 bit against banding

Color depth is the number of brightness gradations per channel (red, green, blue). It sounds dry, but it's exactly what decides whether ugly bands appear on smooth transitions.

JPEG's 8 bits give just 256 levels per channel. On a sunset sky or a smooth gradient that isn't enough — the eye sees stair-step bands, which is what banding means. AVIF, with 10 or 12 bits, gives thousands of gradations and the transition becomes truly smooth. For photographers and designers working with subtle tonal transitions this is a decisive argument.

Wide gamut: BT.2020 and P3

Color depth governs smoothness; the color gamut governs saturation. Gamut is the boundary of which colors a format can show at all. JPEG is usually limited to the old sRGB space. AVIF supports modern wide gamuts:

A wide gamut like Display P3 (the standard on modern phones and laptops) or BT.2020 lets you show the vivid green of grass and a saturated red that would look washed out in sRGB. On a wide-gamut display the difference is clearly visible.

Transparency and animation

AVIF isn't only about photos. It inherits two useful bonuses from its container:

• Transparency (alpha channel). Like PNG — you can make logos and icons with a transparent background. But AVIF is noticeably lighter than PNG, which is valuable for the web.
• Animation. AVIF can store short animated sequences and can replace a bulky GIF at a fraction of the weight.

The result is a surprisingly versatile format: a single AVIF can cover the jobs that used to require JPEG (photos), PNG (transparency) and GIF (animation).

Browser support: an honest map

All these capabilities are useless if there's nowhere to show them. So, honestly, about support. Basic AVIF opens in most modern browsers:

What happens on a regular screen

A fair question: what if I don't have an HDR monitor? No problem. HDR-AVIF on a regular SDR display is shown via tone-mapping — the brightness range is carefully compressed into the standard one so the photo doesn't come out blown-out. You'll see a normal picture, just without the "wow" of the extended range.

The same happens when converting to formats without HDR. When you turn an HDR-AVIF into JPG, our converter performs perceptual tone-mapping: highlights are gently rolled off, shadows stay put, and the output is a properly exposed SDR photo with no blown-out areas.

If transparency matters, choose AVIF to PNG; for a light web version with an alpha channel, AVIF to WebP works well. The full list is on the all formats page.