New interface (AudioDecoderFactory), with an implementation

webrtc/modules/audio_coding/codecs/audio_format.h

Index: webrtc/modules/audio_coding/codecs/audio_format.h
diff --git a/webrtc/modules/audio_coding/codecs/audio_format.h b/webrtc/modules/audio_coding/codecs/audio_format.h
new file mode 100644
index 0000000000000000000000000000000000000000..7ad7edd4293df8ec6cce49081f626303ff0aefc7
--- /dev/null
+++ b/webrtc/modules/audio_coding/codecs/audio_format.h
@@ -0,0 +1,48 @@
+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_AUDIO_CODING_CODECS_AUDIO_FORMAT_H_
+#define WEBRTC_MODULES_AUDIO_CODING_CODECS_AUDIO_FORMAT_H_
+
+#include <map>
+#include <ostream>
+#include <string>
+#include <utility>
+
+namespace webrtc {
+
+// SDP specification for a single audio codec.
+// NOTE: This class is still under development and may change without notice.
+struct SdpAudioFormat {
+  // TODO(kwiberg): Get rid of the default constructor when rtc::Optional no
+  // longer requires it.
+  SdpAudioFormat();
+  SdpAudioFormat(const SdpAudioFormat&);
+  SdpAudioFormat(SdpAudioFormat&&);
+  SdpAudioFormat(const char* name, int clockrate_hz, int num_channels);
+  ~SdpAudioFormat();
+
+  SdpAudioFormat& operator=(const SdpAudioFormat&);
+  SdpAudioFormat& operator=(SdpAudioFormat&&);
+
+  using Parameters = std::map<std::string, std::string>;
+  std::string name;
+  int clockrate_hz;
+  int num_channels;
+  Parameters parameters;
+  // Parameters feedback_parameters; ??
+};
+
+void swap(SdpAudioFormat& a, SdpAudioFormat& b);
+std::ostream& operator<<(std::ostream& os, const SdpAudioFormat& saf);
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_CODING_CODECS_AUDIO_FORMAT_H_