我用DirectShow转WAV格式为mp3是，发先tag=0xFFFE的格式不能转换，除非加入AC3Filter, 我将这个wav的tag标识修改为0x0001(PCM)，就能播放和转换为mp3了，
请问这种wav格式和PCM格式有什么分别？
------解决方案--------------------------------------------------------
tag(0xFFFE) means the WAVEFORMATEX is enhanced by WAVEFORMATEXTENSIBLE
In general oxFFFE is different from PCM(0x1), eg: DTS,AC-3,AAC etc codecs which may ve bigger than 2 chnnels