H.264 Reverse play

base/include/H264Decoder.h

@@ -1,11 +1,18 @@
 #pragma once
 
 #include "Module.h"
+#include <vector>
 
 class H264DecoderProps : public ModuleProps
 {
 public:
-	H264DecoderProps() {}
+	H264DecoderProps(uint _lowerWaterMark = 300, uint _upperWaterMark = 350)
+	{
+		lowerWaterMark = _lowerWaterMark;
+		upperWaterMark = _upperWaterMark;
+	}
+	uint lowerWaterMark;
+	uint upperWaterMark;
 };
 
 class H264Decoder : public Module
@@ -26,10 +33,42 @@ class H264Decoder : public Module
 	bool shouldTriggerSOS();
 
 private:
+	void bufferDecodedFrames(frame_sp& frame);
+	void bufferBackwardEncodedFrames(frame_sp& frame, short naluType);
+	void bufferAndDecodeForwardEncodedFrames(frame_sp& frame, short naluType);
+
 	class Detail;
 	boost::shared_ptr<Detail> mDetail;
 	bool mShouldTriggerSOS;
 	framemetadata_sp mOutputMetadata;
 	std::string mOutputPinId;
 	H264DecoderProps mProps;
-};
+
+	/* Used to buffer multiple complete GOPs 
+	note that we decode frames from this queue in reverse play*/
+	std::deque<std::deque<frame_sp>> backwardGopBuffer;
+	/* buffers the incomplete GOP */
+	std::deque<frame_sp> latestBackwardGop;
+	/* It buffers only one latest GOP 
+	used in cases where partial GOP maybe in cache and rest of the GOP needs to be decoded
+	note that since there is no buffering in forward play, we directly decode frames from module queue*/
+	std::deque<frame_sp> latestForwardGop;
+	std::map<uint64, frame_sp> decodedFramesCache;
+	void sendDecodedFrame();
+	bool mDirection;
+	bool dirChangedToFwd = false;
+	bool dirChangedToBwd = false;
+	bool foundIFrameOfReverseGop = false;
+	bool flushDecoderFlag = false;
+	bool decodePreviousFramesOfTheForwardGop = false;
+	bool prevFrameInCache = false;
+	void decodeFrameFromBwdGOP();
+	std::deque<uint64_t> incomingFramesTSQ;
+	void clearIncompleteBwdGopTsFromIncomingTSQ(std::deque<frame_sp>& latestGop);
+	void saveSpsPps(frame_sp frame);
+	void* prependSpsPps(frame_sp& iFrame, size_t& spsPpsFrameSize);
+	void dropFarthestFromCurrentTs(uint64_t ts);
+	frame_sp mHeaderFrame;
+	boost::asio::const_buffer spsBuffer;
+	boost::asio::const_buffer ppsBuffer;
+};

base/include/H264Metadata.h

@@ -40,9 +40,12 @@ class H264Metadata : public FrameMetadata
 
 		width = metadata.width;
 		height = metadata.height;
+		direction = metadata.direction;
+		mp4Seek = metadata.mp4Seek;
 		//setDataSize();
 	}
-
+	bool direction = true;
+	bool mp4Seek = false;
 protected:
 	void initData(int _width, int _height, MemType _memType = MemType::HOST)
 	{