add debug msg

cgo/ffmpeg/audio.go

@@ -401,6 +401,7 @@ func (self *AudioEncoder) Encode(frame av.AudioFrame) (pkts [][]byte, err error)
 	var pkt []byte
 
 	if frame.SampleFormat != self.SampleFormat || frame.ChannelLayout != self.ChannelLayout || frame.SampleRate != self.SampleRate {
+		fmt.Printf("%+v\n", self)
 		if frame, err = self.resample(frame); err != nil {
 			return
 		}