Added Decoder.ReadStereo() / Decoder.ReadStereoFloat32() using stereo decoding API

stream.go

@@ -171,6 +171,52 @@ func (s *Stream) ReadFloat32(pcm []float32) (int, error) {
 	return int(n), nil
 }
 
+// ReadStereo is the same as Read, but decodes to always two channels
+func (s *Stream) ReadStereo(pcm []int16) (int, error) {
+	if s.oggfile == nil {
+		return 0, fmt.Errorf("opus stream is uninitialized or already closed")
+	}
+	if len(pcm) == 0 {
+		return 0, nil
+	}
+	streams.Save(s)
+	defer streams.Del(s)
+	n := C.op_read_stereo(
+		s.oggfile,
+		(*C.opus_int16)(&pcm[0]),
+		C.int(len(pcm)))
+	if n < 0 {
+		return 0, StreamError(n)
+	}
+	if n == 0 {
+		return 0, io.EOF
+	}
+	return int(n), nil
+}
+
+// ReadStereoFloat32 is the same as ReadStereo, but decodes to float32 instead of int16.
+func (s *Stream) ReadStereoFloat32(pcm []float32) (int, error) {
+	if s.oggfile == nil {
+		return 0, fmt.Errorf("opus stream is uninitialized or already closed")
+	}
+	if len(pcm) == 0 {
+		return 0, nil
+	}
+	streams.Save(s)
+	defer streams.Del(s)
+	n := C.op_read_float_stereo(
+		s.oggfile,
+		(*C.float)(&pcm[0]),
+		C.int(len(pcm)))
+	if n < 0 {
+		return 0, StreamError(n)
+	}
+	if n == 0 {
+		return 0, io.EOF
+	}
+	return int(n), nil
+}
+
 func (s *Stream) Close() error {
 	if s.oggfile == nil {
 		return fmt.Errorf("opus stream is uninitialized or already closed")