PL2 Format That Enables Faster Read Time

Plexon’s newsletter from June 28, 2013 that discusses the ability to load large neural data files. 



June 28, 2013

PL2™ is Here! Load Large Neural Data Files Faster Than Ever!

If your lab generates large neural data files – you do not want to miss this! Introducing Plexon’s new PL2™ format enabling much faster read time over PLX files – 10, 100 or even 1000 times faster!

When continuous wideband data is being recorded at a 40KHz sample rate, the data rate for 16 bit samples is 288MB per hour per channel. That translates to 36.8 GB/hour for 128 channels and 73.7 GB/hour for 256 channels – not including other types of data or file system overhead. The file size can quickly become unwieldy. Even when not recording wideband data, the files can become quite large when the channel count is high. Accordingly, these large, high-resolution files can take a very long time to load for analysis.

To address this issue, Plexon has taken the lead, once again, and advanced its original industry-standard recording format to develop a game-changing new file format – PL2 – that significantly improves the efficiency of the analysis process.

The PL2 file format:

  • Is significantly faster in single channel read time depending on file length, types of data, and number of channels.  Individual channels can be loaded from files hundreds or even thousands of times faster.
  • Enables up to 50% faster block level reads, as in reading the file sequentially.
  • Is a more general format representing all existing PLX data plus more channels and additional types of data including system configuration and individual channel metadata.
  • Generates a somewhat smaller file size compared to Plexon’s previous PLX format.
  • Is recorded in real time by Plexon’s OmniPlex® Neural Data Acquisition System .
  • Requires OmniPlex Software v1.9 or later.
  • Is an option – researchers can choose to record using either the new PL2 format or the original PLX format.
  • Can be created by converting an existing PLX file using PlexUtil 4.0.

According to researcher Nick Steinmetz, Stanford University, “For very large recordings I have made (32 channels, several hours duration, 40kHz sampling rate, as large as 50GB), reading data into MATLAB was very time consuming using the old PLX data format. By converting to the new PL2 format, these files can now be read extremely efficiently, enabling some analyses I couldn’t otherwise perform. Using PL2 has been a fantastic improvement!”

Learn more in our white paper PL2 File System Overview . The suite of PL2-compatible software (including OmniPlex 1.9, PlexUtil 4.0 ,Offline Sorter™ 3.3 ,NeuroExplorer® 4.125  and new PL2 SDKs ) is now available online and can be downloaded from the website’s Support section, Software Downloads area. With the appropriate version license key for the corresponding software program, these PL2-compatible releases are available free of charge.

For more information, contact

Record PL2 Files with OmniPlex v1.9

At the heart of the PL2 launch is the newest software release for the OmniPlex Neural Data Acquisition System. OmniPlex Software v1.9 now records files in the both the original PLX and new PL2 formats, and reduces client latency for DigiAmp™ systems to ~1ms!  You are empowered to acquire and analyze data faster than ever before!

The new PL2 format significantly improves efficiency of analysis of large, high-resolution neural data files. In tests, a file containing ten minutes of spike (SPK), wideband (WB), and field potential (FP) data from 256 channels was recorded in both PLX (13.8GB file) and PL2 (11.4GB file) formats. Single channel reads as performed by Offline Sorter™ and MATLAB® programs resulted in the following:
                                    PLX        PL2
SPK channel:  275.0s     0.18s
WB channel:   275.7s