misc: fix mismatched-tags warnings

Change-Id: I32f59646ad7059dc7440aa6f278fd2e210c8108e

src/media/media_buffer.h

@@ -25,7 +25,7 @@
 #include <memory>
 #include <functional>
 
-class AVFrame;
+struct AVFrame;
 
 namespace DRing {
 struct FrameBuffer; //  from dring/videomanager_interface.h

src/media/media_decoder.h

@@ -40,17 +40,17 @@
 #include <memory>
 #include <chrono>
 
-class AVCodecContext;
-class AVStream;
-class AVDictionary;
-class AVFormatContext;
-class AVCodec;
+struct AVCodecContext;
+struct AVStream;
+struct AVDictionary;
+struct AVFormatContext;
+struct AVCodec;
 enum AVMediaType;
 
 namespace ring {
 
 struct AudioFrame;
-class AudioFormat;
+struct AudioFormat;
 class RingBuffer;
 class Resampler;
 class MediaIOHandle;

src/media/media_filter.h

@@ -28,9 +28,9 @@
 #include <string>
 #include <vector>
 
-class AVFilterContext;
-class AVFilterGraph;
-class AVFilterInOut;
+struct AVFilterContext;
+struct AVFilterGraph;
+struct AVFilterInOut;
 
 namespace ring {
 

src/media/media_io_handle.h

@@ -28,7 +28,7 @@
 #include <vector>
 
 #ifndef AVFORMAT_AVIO_H
-class AVIOContext;
+struct AVIOContext;
 #endif
 
 typedef int(*io_readcallback)(void *opaque, uint8_t *buf, int buf_size);

src/media/video/video_scaler.h

@@ -25,7 +25,7 @@
 #include "noncopyable.h"
 
 
-class SwsContext;
+struct SwsContext;
 
 namespace ring { namespace video {