Data Input-Output Software

		DataIO/X 4.0
		Data Input-Output ActiveX Control and COM Object

  DataIO/X ActiveX Control implements a number of methods that can be used for reading and writing audio WAV files. This gives application developers the ability to develop software for various purposes such as analyzing speech data. In particular, the control provides methods for:

• Opening and Closing WAV files
• Testing to determine whether a binary file is a valid WAV file or not
• Obtaining WAV summary information (Audio Format, Bits Per Channel, Bytes Per Second, Number of Channels, Sample Rate, Number of Samples, Time Length, Data Length, Bytes Per Sample)
• Reading WAV audio data into arrays
• Creating WAV audio files from arrays and specified parameters including output normalization
• Combine with other controls to create larger applications, eg use it with SpeechAnalysis/X to process data for a speech analysis applications.

Features of DataIO/X

DataIO/X is both an ActiveX Control and a COM object, implemented in a single DLL, yet it can be used in a wide range of programming languages that support these standards. The methods can be called in just one line of code from within Excel, Visual Basic 6, Visual Basic .NET, Visual C#, Visual C++ 6, Visual C++ .NET, Delphi and Borland C++ Builder. 

Source Code Examples

• Visual C#
• Visual Basic .NET
• Visual Basic 6
• Excel (VBA)

The control can also be used to quickly create Windows applications for analyzing speech using a range of well known methods. These methods can form the basis of more sophisticated applications. Contact us if you need assistance in creating your application using this component or any others we provide.

Sample Visual Basic .NET application created using DataIO/X. 
A similar application with full source code in Visual C# is also included with the software.

DataIO/X ActiveX Control

Trial Version

If you do have any questions or concerns about using our controls - all you need to do is email us and we will assist you in learning how to use our controls. Just take a look at our testimonials page to see some of the comments we have received from happy customers. we receive many emails from people who have questions about our products or who need a little assistance to get started using an ActiveX control in their program - don't hesitate to contact us and we will be pleased to help you.

Do you require some function that we don't already have? Contact us and we may be able to extend our controls to do what you require.

In the next section, we provide more technical information on the binary file format used for WAV audio files.

WAV Audio Data Format

A brief introduction to binary audio files

Digital audio information consists of sampled data. This means that raw sound waves which vary continuously in time and in magnitude of intensity, are sampled at regular intervals of time, for example, 44100 samples per second is one standard used for audio data. This information is generally sampled with a number of bits of resolution using an analog to digital converter and then stored in a computer file.

To process digital audio information, it is necessary to use a defined standard file format in which to store the data. While it would be feasible to use a text file to do this, there are many reasons why text files are not generally used for this purpose. Primarily, these reasons are concerned with speed and efficiency of the data storage. Text files, while mostly using the ASCII standard, are in a sense, not well defined. There can be different languages used, different end of line characters used, line feeds in some cases and not others limits used in the length of lines and overall of this, require computationally expensive parsing in order to extract information from the file.

Binary files on the other hand, while not in a convenient human readable form, ensure that data can be stored and retrieved in a very precise manner. Information can be stored and retrieved without having ambiguities of text files or the complex processing of string handling. Moreover, since the data is stored in a precise byte-wise arrangement, it is possible to read and write information in a manner not unlike random access memory (RAM).

The binary file format requires that each sampled data point uses a fixed number of bytes. The number of bytes determines the magnitude resolution. For example if we choose an 8-bit or 1-byte storage resolution, this means that there are 255 possible levels of the signal data. If we use a 16 bit audio format, then 2 bytes per sample per channel are used with a given resolution of 32768 levels. Higher quality sound definition requires that a sufficiently high sample rate is used and a sufficient number of bits are used. However the area of sound quality is complex and we will not discuss this issue here.

There are binary many audio file standards and in the next section, we discuss the WAV standard, which is handled by DataIO/X.

WAV Binary File

The WAV audio standard actually has many variations. Not all of these are in widespread use, and DataIO/X is not designed to be able to process all of them. The WAV audio standard that is able to be processed by DataIO/X is defined in the table below. This WAV file format is sometimes called the Canonical WAV or WAVE file format.

There are numerous variations on this theme, and the DataIO/X component provides some methods which enables the user to determine if the binary file is valid in terms of the above format. It is possible that the file may be a WAV format which uses a different format and in this case, DataIO/X will still report the format as being invalid, that is not able to be processed by DataIO/X.