Nex5 File Format

NeuroExplorer Version 5.016 (released on July 3, 2015) supports new .nex5 data file format that is more flexible than .nex file format.

The new new .nex5 file format overcomes the following limitations of .nex file format:

Maximum File Size

  • .nex files are limited to 2 GB size; .nex5 files can be as big as 16 TB

Maximum Duration of Recording Session

  • .nex files use 32-bit timestamps and the maximum timestamp value is 2**31 time ticks which corresponds to about 15 hours when using 40 KHz sampling rate. In .nex5 files, the timestamps can be saved as 64-bit integers and maximum timestamp corresponds to more than 7 million years.

Limited Precision of Continuous Channel Values

  • .nex files use 16-bit integers to save continuous values. In .nex5 files, continuous channels values can be saved as 32-bit floating values.

Limited Channel Metadata

  • .nex files can store only a few metadata values for each channel (wire number, unit number, etc). In .nex5 files, unlimited metadata for the whole file and for every file variable can be stored.

nex5 format is designed to be similar to nex format so that the code that reads and writes .nex files would need only small modifications to implement reading and writing .nex5 files.

Full .nex5 file format specification as well as C++ code, Matlab code and Python code for reading and writing .nex5 files are available in the following files: