WebP vs AVIF: Encoding, Compression, and Browser Support

WebP uses VP8 intra-encoding, which is based on predictive residual coding. It divides images into 16x16 luma blocks and corresponding chroma blocks, provides only 4 intra prediction modes, has a relatively simple encoding process, and lower computational complexity.

AVIF uses AV1 intra-encoding, supports variable size block partitioning from 4x4 to 64x64, provides up to 56 intra prediction directions, and adds new modes such as angular prediction and directional prediction, which can fit local texture details of images more accurately.

VP8 intra-encoding does not use in-loop filtering optimization. AV1 intra-encoding adds in-loop deblocking filtering and noise reduction, which can reduce blocking artifacts and contour distortion caused by compression, resulting in smoother subjective image quality at the same bitrate.

Public measured data from domestic CDN vendors shows that at the same subjective image quality, AVIF file sizes are 15% to 30% smaller than WebP. The compression ratio improvement for natural photographic images is higher than that for vector and graphic images.

WebP file sizes are 25% to 35% smaller than traditional JPEG. AVIF has a more obvious compression ratio advantage in high-definition photography and large-size image scenarios. In low-quality preview scenarios, the compression ratio difference between the two narrows to less than 10%.

In current public test results, no case of AVIF having a larger file size than WebP at equal image quality has been recorded. Only in graphics images where solid color blocks account for more than 80% of the area, the compression ratio difference between the two is less than 5%.

Both formats support alpha channels and animation, but there are differences in detailed implementation. WebP supports 8-bit alpha transparency, while AV1 supports 10-bit and 12-bit alpha transparency, resulting in smoother transparency gradients.

In terms of HDR support, WebP only supports basic storage of static HDR, and full PQ and HLG decoding adaptation has not been widely implemented. AVIF natively supports 10-bit color depth, HDR10 and wide color gamut, and is adapted to current wide-gamut display devices.

In terms of animation support, WebP has lower single-frame encoding complexity, and playback decoding resource usage is lower than AVIF animation. AVIF animation has a file size about 20% smaller than WebP animation at the same image quality.

As of 2024, the global browser support coverage for WebP exceeds 96%, and most mainstream browser versions can parse and display WebP images normally.

The browser support coverage for AVIF is approximately 84%, which is lower than WebP. AVIF images cannot be displayed normally on older macOS and iOS devices running Safari versions lower than 16.4.

For e-commerce product large images and marketing banner scenarios, prioritize AVIF with a WebP fallback solution. This reduces storage and bandwidth costs while covering users on older browsers, and ensures cost control for high-traffic scenarios.

For product list thumbnails and product detail page icon scenarios, WebP is sufficient to meet requirements. In this scenario, individual image sizes are already small, the benefit from improved compression ratio is limited, and WebP has faster decoding speed.

For product display animated images and advertising animated images, choose AVIF when bandwidth is a priority and compatibility requirements are low, and choose WebP when wide coverage and high decoding performance are required. You can use OKfmt's WebP to AVIF converter to complete pre-conversion format testing.