┌────────────────────────────────────────────────┐
│ The Microsoft Multimedia WAV Sound File Format │
└────────────────────────────────────────────────┘
Written for the PC-GPE by Mark Feldman
e-mail address : u914097@student.canberra.edu.au
myndale@cairo.anu.edu.au
┌───────────────────────────────────────────┐
│ THIS FILE MAY NOT BE DISTRIBUTED │
│ SEPARATE TO THE ENTIRE PC-GPE COLLECTION. │
└───────────────────────────────────────────┘
┌────────────┬───────────────────────────────────────────────────────────────
│ Disclaimer │
└────────────┘
I assume no responsibility whatsoever for any effect that this file, the
information contained therein or the use thereof has on you, your sanity,
computer, spouse, children, pets or anything else related to you or your
existance. No warranty is provided nor implied with this information.
┌──────────────────────┬─────────────────────────────────────────────────────
│ The RIFF File Format │
└──────────────────────┘
WAV files use the RIFF file structure. The RIFF format was designed
for multi-media purposes. A RIFF files consists of a number of "chunks":
┌────────────────────────────────────────────────────────────────────────┐
│ Byte Length │
│ Offset Name (in bytes) Description │
├────────────────────────────────────────────────────────────────────────┤
│ 00h rID 4h Contains the characters "RIFF" │
│ 04h rLen 4h The length of the data in the next chunk │
│ 08h rData rLen The data chunk │
└────────────────────────────────────────────────────────────────────────┘
┌──────────────────────────┬─────────────────────────────────────────────────
│ The WAVE Form Definition │
└──────────────────────────┘
The rData chunk in a WAV file is split up into several further chunks:
┌─────────────────────────────────────────────────────────────────────────┐
│ rData │
│ Byte Length │
│ Offset Name (in bytes) Description │
├─────────────────────────────────────────────────────────────────────────┤
│ 00h wID 4h Contains the characters "WAVE" │
│ 04h Format 14h Contains data which specifies the format │
│ Chunk of the Data in the Data Chunk │
│ 18h WAVE Data ? Contains the WAV audio data │
│ Chunk │
└─────────────────────────────────────────────────────────────────────────┘
┌──────────────────┬─────────────────────────────────────────────────────────
│ The Format Chunk │
└──────────────────┘
The Format Chunk is split up into these fields:
┌─────────────────────────────────────────────────────────────────────────┐
│ Format │
│ Chunk Length │
│ Offset Name (in bytes) Description │
├─────────────────────────────────────────────────────────────────────────┤
│ 00h fId 4 Contains the characters "fmt" │
│ 04h fLen 4 Length of data in the format chunk │
│ 08h wFormatTag 2 * │
│ 0Ah nChannels 2 Number of channels, 1=mono, 2=stereo │
│ 0Ch nSamplesPerSec 2 Playback frequency │
│ 0Eh nAvgBytesPerSec 2 ** │
│ 10h nBlockAlign 2 *** │
│ 12h FormatSpecific 2 Format specific data area │
└─────────────────────────────────────────────────────────────────────────┘
* The wFormatTag specifies the wave format, eg 1 = Pulse Code Modulation
(or in plain english, regular 8 bit sampled uncompressed sound)
** Indicates the average number of bytes a second the data should be
transferred at = nChannels * nSamplesPerSec * (nBitsPerSample / 8)
*** Indicates the block alignment of the data in the data chunk. Software
needs to process a multiplt of nBlockAlign at a time.
nBlockAlign = nChannels * (nBitsPerSample / 8)
┌────────────────┬───────────────────────────────────────────────────────────
│ The Data Chunk │
└────────────────┘
The Data Chunk is split up into these fields:
┌─────────────────────────────────────────────────────────────────────────┐
│ Data │
│ Chunk Length │
│ Offset Name (in bytes) Description │
├─────────────────────────────────────────────────────────────────────────┤
│ 00h dId 4 Contains the characters "data" │
│ 02h dLen 4 Length of data in the dData field │
│ 00h dData dLen The actual waveform data │
└─────────────────────────────────────────────────────────────────────────┘
In mono 8-bit files each byte represents one sample. In stereo 8-bit files
two bytes are stored for each sample, the first byte is the left channel
value, the next is the right channel value.