The encoder supports three categories of encoded output: Windows Media Audio Standard, Windows Media Audio Professional, and Windows Media Audio Lossless. Micronas Semiconductors, Inc.The Windows Media Audio encoder encodes audio streams. MM SYCOM ACM SYC701 CELP68 S圜om Technologies MM SYCOM ACM SYC701 CELP54 S圜om Technologies MM SYCOM ACM SYC701 G726L S圜om Technologies Windows Media Audio V2 V7 V8 V9 / DivX audio (WMA) / Alex AC3 Audio Compression codesĪ list of defined compression codes is as follows. When the sampling resolution is 32-bit, the data would typically be signed floating point between -1 and 1 and silence would be 0. When the sampling resolution of uncompressed PCM files is 16-bit or 24-bit, the audio samples in the data chunk are signed integers. Thus, audio samples range between 0 and 255 (0x00 and 0xFF) and silence is 127 (0x7F). A note on sampling resolution and data representationīy convention, (although different data representations are possible), when the sampling resolution of uncompressed PCM files (compression code 1) is 8-bit, the audio samples in the data chunk use unsigned integer numbers. If the audio data contains an odd number of bytes, it should be padded with a zero byte, although this byte will not be counted in the size variable. Also, all information has to be word aligned (at every two bytes). This field may or may not be presentĪs with all information in wave files, data is stored little-endian. These bytes define the number of extra format bytes to follow in the format chunk. A typical sampling resolution is 16 bits per sample, but could be anything greater than 1 These bytes define the sampling resolution of the file. For example, a PCM wave that has a sampling resolution of 16 bits (2 bytes) and has 2 channels will record a block of samples in 2 * 2 = 4 bytes For example, a PCM wave file that has a sampling rate of 44100 Hz, 1 channel, and sampling resolution of 16 bits (2 bytes) per sample, will have an average number of bytes equal to 44100 * 2 * 1 = 88,200 An example sampling rate is 44100 = 0x0000AC44 for 44,100 Hz

The typical number of channels is 1 in mono waves and 2 in stereo waves A typical compression code is 1, signifying uncompressed Pulse Code Modulation (PCM). The usual size of the format chunk is 16, unless there are any extra format bytes (see below) The size of the format chunk (number of bytes) less 8 (less the 'chunk ID' and the 'size'). The ASCII character string 'fmt ' (note the space at the end)

The format chunk in the Wave file format has the following structure.

0x0003 ieee float codec