//ffmpeg -i sunpay_connectfail.mp3 -ar 48000 -ac 2 -f s16le -y 48000_ac2_s16le.pcm//ffmpeg -i sunpay_connectfail.mp3 -ar 12800 -ac 1 -f s16le -y 12800_ac1_s16le.pcmar:采样率ac:通道数