BPG: better quality at same size as JPEG

image_editor_compWhen it comes to images, JPEG is undoubtedly the most widely use format. Be it the web or pictures taken by your digital camera, JPEG is everywhere. Even Google’s acquired image format WEBP couldn’t challenge the supremacy. The reason is simple – JPEG gives better quality at a smaller size than most of the commonly known image formats. However, JPEG uses a lossy algorithm and there’s always a loss of quality.

BPG (Better Portable Graphics) is a new image file format that intends to challenge the supremacy of JPEG on the web. BPG gives better image quality than JPEG at the same size. The format is a derivative of the HEVC standard video format. Here’s a visual comparison.

Advantages

  • High compression ratio.
  • Supported by most Web browsers with a small Javascript decoder (gzipped size: 76 KB).
  • Based on a subset of the HEVC open video compression standard.
  • Supports the same chroma formats as JPEG to reduce quality loss during the conversion. An alpha channel, RGB, YCgCo and CMYK color spaces are also supported.
  • Native support of 8 to 14 bits per channel for a higher dynamic range. JPEG or WEBP support only 8 channels.
  • Lossless compression supported.
  • Metadata (such as EXIF) can be included.
  • Can handle transparency, which JPEG can’t.

HEVC (and hence BPG) won by a wide margin in Mozilla’s study of various lossy compressed image formats. The files are little smaller than raw HEVC as the BPG header is smaller. It gives a higher dynamic range (which is important for cameras and new displays) and a slightly better compression ratio (because there are less rounding errors in the decoder). BPG uses high quality decimation. Besides the software implementation, BPJ is also supported by hardware with standard HEVC decoders and encoders.

Webpage: BPG

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