Aird: A computation-oriented mass spectrometry data format enables a higher compression ratio and less decoding time

We describe "Aird", an opensource and computation-oriented format with controllable precision, flexible indexing strategies, and high compression rate. Aird provides a novel compressor called Zlib-Diff-PforDelta (ZDPD) for m/z data. Compared with Zlib only, m/z data size is about 55% lower in Aird on average. With the high-speed decoding and encoding performance brought by the Single Instruction Multiple Data(SIMD) technology used in the ZDPD, Aird merely takes 33% decoding time compared with Zlib. We used the open dataset HYE, which contains 48 raw files from SCIEX TripleTOF 5600 and TripleTOF6600. The total file size is 206GB as the vendor format. The total size increases to 854GB after converting to mzML with 32-bit encoding precision. While it takes only 189GB when using Aird. Aird uses JavaScript Object Notation (JSON) for metadata storage. Aird-SDK is written in Java and AirdPro is a GUI client for vendor file converting which is written in C#. They are freely available at https://github.com/CSi-Studio/Aird-SDK and https://github.com/CSi-Studio/AirdPro.