OptimFROG

OptimFROG is a proprietary, lossless audio codec developed by Florin Ghido. OptimFROG is optimized for high compression (small file sizes) at the expense of encoding and decoding speed, and consistently measures among the highest compressing lossless codecs.^[3][4] OptimFROG comes with three compressors: a lossless codec for integer LPCM format in WAV files, one for IEEE 754 floating-point WAV files, and third codec called DualStream.

OptimFROG

Developer(s)	Florin Ghido
Stable release	5.100 / September 2, 2016; 8 years ago (2016-09-02)
Operating system	FreeBSD, Linux, OS X, Microsoft Windows
Type	Audio codec
Website	losslessaudio.org

OptimFROG Audio file format

Filename extensions	.off (OptimFROG Float) .ofr (OptimFROG Lossless) .ofs (OptimFROG Small,  a/k/a DualStream)
Internet media type	audio/x-off audio/x-ofr audio/x-ofs
Developed by	Florin Ghido
Initial release	December 20, 2001; 23 years ago (2001-12-20)[1]
Latest release	5.100 September 2, 2016; 8 years ago (2016-09-02)
Type of format	Audio codec
Compression	Lossless/lossy hybrid
Open format?	No[2]
Free format?	Yes[2]
Website	losslessaudio.org

OptimFROG DualStream is lossy, but fill the gap between perceptual coding and lossless coding by producing a correction file. In combination with the main, lossy-encoded file, the correction file provides for lossless decoding. The lossless decoding is computationally intense and cannot be done in real time on contemporary hardware.^[5] The rival audio codecs WavPack. MPEG-4 SLS, and DTS-HD Master Audio also offer correction file generation.

The OptimFROG file formats use APEv2 tags to store the metadata. ID3 is also possible.