Better Portable Graphics

Better Portable Graphics
Filename extension .bpg
Magic number 42 50 47 fb
Initial release 2014 (2014)
Latest release
0.9.6
(September 2015 (2015-09))
Type of format lossy lossless bitmap image format
Extended from HEVC
Open format? Yes
Website bellard.org/bpg

Better Portable Graphics (BPG) is a file format for coding digital images, which was created by programmer Fabrice Bellard in 2014. Its purpose is to be a more compression-efficient replacement for the JPEG image format when quality or file size is an issue.[1] It is based on the intra-frame encoding of the High Efficiency Video Coding (HEVC) video compression standard.[2] Tests on photographic images have shown that BPG produces significantly smaller files for a given quality than any other graphics file format.[3]

While there is not yet built-in native support for BPG in any mainstream browsers, websites can still use BPG images in all browsers by including a 56KB (after gzipping) JavaScript library made by Bellard.[1]

High Efficiency Video Coding and BPG

HEVC already has several profiles defined for still-picture coding using HEVC's intra-frame encoding for various bit depths and color formats, including the progressively more capable Main Still Picture, Main 4:4:4 Still Picture, and Main 4:4:4 16 Still Picture profiles.

BPG is essentially a wrapper for uses of the HEVC's Main 4:4:4 16 Still Picture profile up to 14 bits per sample.

Specifications

BPG's container format is intended to be more suited to a generic image format than the raw bitstream format used in HEVC (which is otherwise ordinarily used within some other wrapper format, such as the .mp4 file format).[2][4]

BPG supports the color formats known as 4:4:4, 4:2:2, and 4:2:0.[2] Support for a separately coded extra channel is also included for an alpha channel or the fourth channel of a CMYK image.[2] Metadata support is included for Exif, ICC profiles, and XMP.[2]

Color space support is included for YCbCr with ITU-R BT.601, BT.709, and BT.2020 (non-constant luminance) definitions, YCgCo, RGB, CMYK, and grayscale.

Support for HEVC's lossy and lossless data compression is included.

BPG supports animation.[1]

Patents

BPG is believed to be covered by some of the patents on HEVC, and as such, any device which is licensed to support HEVC will also be covered for BPG. Yet some sites such as LWN.net conclude that it is unlikely that BPG will replace JPEG, despite BPG's technical superiority.[4] There doesn't seem to be any evaluation available online of which patents affect BPG. This also means that it is not yet known when any patents will expire, and BPG would therefore become patent-free. Given the 20-year term of US patents and the 2014 publishing date of BPG, the expiry date of latest HEVC patent should be no later than 2034.

Other proposed JPEG replacements

Several previous image formats are also technically superior to JPEG for similar uses, though not by the same margin as BPG. They have found some niche uses, but have crucially not gained acceptance on the web. Investigations for a possible JPEG replacement have included:[3][5]

References

  1. 1 2 3 "BPG Image format". Fabrice Bellard. 2014. Retrieved 2016-04-02.
  2. 1 2 3 4 5 "BPG specification". Retrieved December 2014.
  3. 1 2 "Lossy Compressed Image Formats Study". Mozilla Corporation. Retrieved 2015-02-10.
  4. 1 2 "BPG, a still-image format from video compression". LWN.net.
  5. ↑ "BPG Image Comparison". Retrieved 2015-02-10.

External links

This article is issued from Wikipedia - version of the Saturday, April 02, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.