Software lossy and lossless compression in DAQmx.

[lukko]

Right now lossy and lossless compression can be achieved as presented here: Data Compaction for High-Speed Streaming to Disk where AI.RawDataCompressionType and AI.LossyLSBRemoval.CompressedSampleSize are used (see figure below).

In this case raw data are stored and additional header info has to be added. The idea is to implement and optimize it in DAQmx (DAQmx Configure Logging VI). This will allow high-speed streaming and to save disk space for higher sampling rates or long-term measurements.

Afterward implementation in the TDMS API could help to read directly compressed raw data without additional operations in LV. This will allow to work on TDMS files in Excel or Matlab using nilibdds.dll.

The issue is discussed a little here: Why the TDMS file is larger than it should be.

What do you think about it?

Lukasz Kocewiak