BPG Image format
BPG (Better Portable Graphics) is a new image format. Its purpose is
to replace the JPEG image format when quality or file size is an
issue. Its main advantages are:
- High compression ratio. Files are much smaller than JPEG for
(gzipped size: 56 KB).
- Based on a subset of
open video compression standard.
- Supports the same chroma formats as JPEG (grayscale, YCbCr 4:2:0,
4:2:2, 4:4:4) to reduce the losses during the conversion. An alpha
channel is supported. The RGB, YCgCo and CMYK color spaces are also
- Native support of 8 to 14 bits per channel for a higher dynamic range.
- Lossless compression is supported.
- Various metadata (such
as EXIF, ICC profile, XMP)
can be included.
- Animation support.
The following archive contains the source code of the bpgenc,
bpgdec and bpgview command line utilities (for
Linux) and the associated libbpg library (read the README
file in the archive). It also includes the source code of the
Binary distribution for Windows (64 bit only): bpg-0.9.8-win64.zip
Unofficial Github mirror.
For Mac users, the BPG utilities are available in the libbpg Homebrew formula.
- Mozilla did
of various lossy compressed image formats. HEVC (hence BPG) was a
clear winner by a wide margin. BPG files are actually a little
smaller than raw HEVC files because the BPG header is smaller than
the corresponding HEVC header.
- BPG natively supports 8 to 14 bits per channel when most other
formats use 8 bits (including most of the JPEG implementations
and WEBP). 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 (10 tap Lanczos filter) and
interpolation (7 tap Lanczos filter) to handle the chroma samples in
4:2:2 and 4:2:0 formats.
- BPG can be supported in hardware with standard HEVC decoders and
encoders (it uses a subset of the Main 4:4:4 16 Still Picture Profile,
The specification of the BPG file format is
- The BPG decoding library uses a modified version of FFmpeg
released under the LGPL version 2.1 as HEVC decoder. The BPG decoding
library excluding the FFmpeg code is released under the BSD license.
- The BPG encoder as a whole is released under the GPL version 2
license. The BPG encoder sources excluding x265 are released under the
license. The x265
library is released under the GPL version 2 license. The optional
JCTVC HEVC reference
encoder is released under the BSD license.
- Some of the HEVC algorithms may be protected by patents in some
countries (read the FFmpeg
Patent Mini-FAQ for more information). Most devices already include
or will include hardware HEVC support, so we suggest to use it if
patents are an issue.
Fabrice Bellard - http://bellard.org/