loopback capture audio that is being played on PC adapted from windows sample:capturing a stream 直接抓取电脑上的音频 不需要通过喇叭和麦克风再捕捉，直接内部完成 改自windows的官方例程: https://docs.microsoft.com/en-us/windows/desktop/coreaudio/capturing-a-stream 之后考虑直接转化格式成pcm 16bit 然后用来语音识别