feat: add support of codec plugin

ext-codec/Opus.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2016-present The ZLMediaKit project authors. All Rights Reserved.
+ *
+ * This file is part of ZLMediaKit(https://github.com/ZLMediaKit/ZLMediaKit).
+ *
+ * Use of this source code is governed by MIT-like license that can be found in the
+ * LICENSE file in the root of the source tree. All contributing project authors
+ * may be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef ZLMEDIAKIT_OPUS_H
+#define ZLMEDIAKIT_OPUS_H
+
+#include "Extension/Frame.h"
+#include "Extension/Track.h"
+
+namespace mediakit {
+
+/**
+ * Opus帧音频通道
+ */
+class OpusTrack : public AudioTrackImp{
+public:
+    using Ptr = std::shared_ptr<OpusTrack>;
+    OpusTrack() : AudioTrackImp(CodecOpus,48000,2,16){}
+
+private:
+    //克隆该Track
+    Track::Ptr clone() const override {
+        return std::make_shared<OpusTrack>(*this);
+    }
+    //生成sdp
+    Sdp::Ptr getSdp(uint8_t payload_type) const override ;
+};
+
+}//namespace mediakit
+#endif //ZLMEDIAKIT_OPUS_H