以编程方式将G729音频转换为WAV PCM

I have G729 encoded audio files. I need to programmatically convert them to WAV PCM (16bit 8kHz mono) in the flow of a tool that is doing other thing too. I have an executable that will do that for me. But spawning that external process every time I convert is too heavy on resources. Especially if I need many of them being done in parallel. Looking for a .NET library or code that will let me call this inside my process.I have G729 encoded audio files. I need to prog