View Full Version : Re: Altering Headers on VAD files

05-11-2008, 10:59 PM
Dear Dave McGurl and others,

Motion Lab Systems supported the original VAD file structure for files produced by the Vicon 370 systems but the format changed at some point and Vicon have not, to my knowledge, documented the changes. As a result our support for VAD files is limited to RData2 - sales of the RData2 product for VAD support are non-existent.

Instead of trying to modify the proprietary VAD format I'd suggest that you consider using your Vicon system to create C3D files containing the analog data - and then modify the C3D files. Although C3D is considered as 3D file format, it works extremely well as an analog data only format.

The C3D format is a public format (documented on the www.c3d.org website) and is well supported with documentation (a printable manual can be downloaded) and several free tools. The MLSviewer displays the contents of the file - full data, data parameters and header information and the C3Dserver allows the C3D files to be created and modified (including adding channels of data) from within most other applications - VB, Java, C++, C#, MATLAB, etc and includes a simple C3D file editor with full VB source code. These applications, and others, can be downloaded from our website.

Full Disclosure Statement: Motion Lab Systems sells several C3D applications including EMG Analysis programs, a full featured C3D file editor and other C3D related applications. The MLSviewer application is supplied at no charge, the C3Dserver SDK is available in two versions, the slower version is free, we offer a faster version for sale.

Edmund Cramp - eac@motion-labs.com
Motion Lab Systems, Inc. - http://www.motion-labs.com
15045 Old Hammond Highway, Baton Rouge, LA 70816 USA
Tel: (Central Time Zone, GMT-6)

> -----Original Message-----
> From: * Biomechanics and Movement Science listserver
> [mailto:BIOMCH-L@NIC.SURFNET.NL] On Behalf Of Dave McGurl
> Sent: Friday, May 09, 2008 8:57 AM
> Subject: [BIOMCH-L] Altering Headers on VAD files
> Dear Subscribers,
> We are currently using a Vicon system to capture motion data
> in our lab.
> Vicon saves the analog data as a .vad file. These files are
> in a binary format that I am unfamiliar with. We currently
> have several subjects where the sampling frequency and other
> parameters that are contained in the header of these files
> were changed during testing. I need to find a way to alter
> the header of these files to change the number of
> channels/sampling frequency/etc.
> I currently have tried such programs from Motion Lab Systems
> (RDATA2, C3DViewers, etc) but none of these files allow me to
> alter the header and resave the data, at least from what I have found.
> Does anyone have any experience with these vad files or has
> figured out a way to decode the binary header?
> Any suggestion would be greatly appreciated.
> Thank You,
> Dave McGurl
> --
> (412) 624-9898
> University of Pittsburgh
> Department of Bioengineering
> 749 Benedum Hall
> 3700 O'Hara Street
> Pittsburgh, PA 15261
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