CVU file is a CVSD Unfiltered Audio. Continuously Variable Slope Delta modulation (unfiltered) is an alternative handler for CVSD that is unfiltered but can be used with any bit-rate.
WMA is a proprietary audio container format of Microsoft. There are 4 codec used in WMA – WMA, WMA Professional, WMA Lossless and WMA Voice. It uses one of the four WMA codec to encode audio. WMA contains the audio file in Advanced Systems Format (ASF) format. The ASF file decides how the metadata will be encoded.