SOFTWARE

I tried to make the code as simple and as minimal as possible so it would be easy to understand. The code currently supports WAV and MP3 formats. You can find information about both formats on the Internet if you’re interested.

The WAV file format supports a variety of bit resolutions, sample rates, and channels of audio. A WAV file is a collection of a number of different types of chunks. There is a required format (“fmt”) chunk, which contains important parameters describing the waveform, such as its sample rate. The data chunk, which contains the actual waveform data, is also required. The other chunks are optional.

The minimal WAV file consists of a single WAV containing the two required chunks: a format chunk and a data chunk. There are a number of variations on the WAV format, but if you convert from CD to WAV format, then most of the software will create the simplest WAV file.

MP3 is the other popular audio file format for compressed data. MP3 files are composed of a series of frames. Each frame of data is preceded by a header, which has extra information about the data to come. Extra information, which is called ID3 data, may be included at the beginning or end of an MP3 file. Figure 3 (p. 45) shows the MP3 format with a hex representation of bytes and an explanation. You can investigate it by opening the file in any hex editor. I use WinHex because it has a disk utility as well. All of the source code is posted on the Circuit Cellar FTP site.