Adobe 22011292 User Guide - Page 49

ADOBE AUDITION 35 User Guide Windows PCM (.wav) The Microsoft Windows WAV format supports both mono and stereo files at a variety of resolutions and sample rates. It follows the RIFF (Resource Information File Format) specification, and allows for extra user information to be embedded and saved with the wave file. WAV files contain PCM coded audio - which is pure, uncompressed Pulse Code Modulation formatted data. Options These formatting options are available only to 32-bit files; they'll be disabled ("grayed-out") at other times: • 32-bit 24.0 float (type 1 - 24-bit) saves full 32-bit floats (in the range of +/-8million), but the .wav BitsPerSample field is set to 24 while BlockAlign is still set to 4 bytes per channel. • 32-bit 16.8 float (type 1 - 32-bit) is Adobe Audition's internal format. Floating point values are in the range of +/32768.0, but larger and smaller values are valid and not clipped since the floating point exponent is saved as well. The .wav BitsPerSample field is set to 32 and BlockAlign is set to 4 bytes per channel. • 32-bit 0.24 normalized float (type 3 - 32-bit) is the standard floating point format for type 3 .wav files. Values are normalized to the range +/-1.0 and although values above and below this range are saved, some programs may clip when reading them back in. (Adobe Audition will not clip, but read the same value back if it's beyond this range.) • 24-bit pack int (type 1 - 24-bit) saves straight 24-bit integers so any data beyond the bounds are clipped. The .wav BitsPerSample field is set to 24 and BlockAlign is set to 3 bytes per channel. • 24-bit packed int (type 1 - 20-bit) saves straight 24-bit integers (so any data beyond the bounds is clipped). The .wav BitsPerSample field is set to 20 and BlockAlign is set to 3 bytes per channel. The extra 4 bits that are saved are actually the remaining valid bits when saving, and are used when reading (thus still giving 24-bit accuracy if those bits were actually present when writing). Applications should either fill those last 4 bits with zeros, or with actual data, but generally analog/digital converters that generate 20 bits of valid data automatically set the remaining 4 bits to zero. Any type 1 format with BlockAlign set to 3 bytes per channel is assumed to be packed integers, and a BitsPerSample field between 17 and 24 inclusively will read in all 24 bits and assume the remaining bits are either accurate or set to zero. • 32-bit int (type 1 - 32-bit) saves 32-bit audio as 32-bit integers. • Enable Dithering will dither 32-bit files when saving to a PCM format (20-bit, 24-bit, or 32-bit). This option is only available if you have a 32-bit file and you select to save it as a nonfloating-point type format. The dither used is a Triangular dither, depth 1.0, with no noise shaping. If you wish to apply a noise shaped dither, use Edit > Convert Sample Type... to dither the audio first, then save without dither enabled in the file format options. Windows Media Audio(.wma) The Windows Media Audio filter enables Adobe Audition to directly encode (save) and decode (open) .wma files. When a file is saved as a .wma file, it's encoded and compressed as specified by the .wma settings. As a .wma file is opened, it's decompressed into Adobe Audition's uncompressed internal format. This allows you to save the .wma file back to disk as any file format (including as a standard .wav file). Check your online documentation and help for details on the options for saving Windows Media Audio files.