feat: add support of codec plugin

ext-codec/G711.h

@@ -0,0 +1,33 @@
+/*
+ * 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_G711_H
+#define ZLMEDIAKIT_G711_H
+
+#include "Extension/Frame.h"
+#include "Extension/Track.h"
+
+namespace mediakit{
+
+/**
+ * G711音频通道
+ */
+class G711Track : public AudioTrackImp{
+public:
+    using Ptr = std::shared_ptr<G711Track>;
+    G711Track(CodecId codecId, int sample_rate, int channels, int sample_bit) : AudioTrackImp(codecId, 8000, 1, 16) {}
+
+private:
+    Sdp::Ptr getSdp(uint8_t payload_type) const override;
+    Track::Ptr clone() const override;
+};
+
+}//namespace mediakit
+#endif //ZLMEDIAKIT_G711_H