New Ultra Fast Lossless Audio Codec (HALAC)

HALAC (High Availability Lossless Audio Compression)

2023-12-31 21:12:23

I'm new in this forum. I am glad it was such a special forum on Audio. I am the writer of the lossless image codec called HALIC(High Availability Lossless Image Compression). It is a work that can offer a good compression ratio quite quickly. This time I would like to introduce my work called HALAC(High Availability Lossless Audio Compression).

In the past(2018-2019), I had been working on the lossless audio compression. However, I could not bring together the work I did. Now I have a little time and I think I developed a fast codec. I worked on 16 bit, 2 channel audio data (.wav). Higher bit and channel options can be added if necessary. As a result, the approach is the same.

HALAC, like the HALIC, focuses on a reasonable compression ratio and high processing speed. The compression rate for audio data is usually limited. So I wanted a solution that can work faster with a few percent concessions.

I used a quick estimation with ANS(FSE). I don't know if there are other codecs using ANS, but the majority uses "Rice Coding". However, in my tests, Rice Coding(my own implementation) is a bit behind in terms of speed(0.6x - 0.7x), but it gives better results as compression rate(1% - 2%). The loss of speed in the Rice Coding is due to the calculation of adaptive parameter. I am really happy with ANS right now because speed is more important to me. In addition, I do not think that I use ANS fully efficiently.

GPU or SIMD was not used. Also now in the single-thread version. In the next version, I can add the Multithread option. I couldn't compile the Linux version because my Linux machine collapsed. I tried to find the middle way by working with different music genres.
Below are the comparisons (from original wav, 16 bit, 2 channel, 44100 bps) with FLAC, ALAC and WAVPACK (Pazera_Free_Audio_Extractor ver. 2.11).

Test Machine (2012): i7 3770k, 3.9 ghz, 16 gb ram, 256 gb ssd
Encode Usage: halac_encode.exe input.wav out.halac
Decode Usage: halac_decode.exe out.halac original.wav