timeBase was propagated incorrectly, so replaced it by a more robust, proper MetaData system that separates frame rate from time base

Author: Raveler

source/ffmpeg-cpp/ffmpeg-cpp/Demuxing/AudioInputStream.cpp

@@ -2,8 +2,8 @@
 
 namespace ffmpegcpp
 {
-	AudioInputStream::AudioInputStream(AudioFrameSink* frameSink, AVStream* stream)
-		: InputStream(stream)
+	AudioInputStream::AudioInputStream(AudioFrameSink* frameSink, AVFormatContext* format, AVStream* stream)
+		: InputStream(format, stream)
 	{
 		SetFrameSink(frameSink);
 	}

source/ffmpeg-cpp/ffmpeg-cpp/Demuxing/AudioInputStream.h

@@ -11,7 +11,7 @@ namespace ffmpegcpp
 
 	public:
 
-		AudioInputStream(AudioFrameSink* frameSink, AVStream* stream);
+		AudioInputStream(AudioFrameSink* frameSink, AVFormatContext* format, AVStream* stream);
 		~AudioInputStream();
 
 	protected:

source/ffmpeg-cpp/ffmpeg-cpp/Demuxing/InputStream.cpp

@@ -6,9 +6,10 @@ using namespace std;
 
 namespace ffmpegcpp
 {
-	InputStream::InputStream(AVStream* stream)
+	InputStream::InputStream(AVFormatContext* format, AVStream* stream)
 	{
 		this->stream = stream;
+		this->format = format;
 
 		// find decoder for the stream
 		AVCodec* codec = CodecDeducer::DeduceDecoder(stream->codecpar->codec_id);
@@ -85,14 +86,43 @@ namespace ffmpegcpp
 			av_frame_free(&frame);
 			frame = nullptr;
 		}
+		if (metaData != nullptr)
+		{
+			delete metaData;
+			metaData = nullptr;
+		}
 	}
 
 	void InputStream::SetFrameSink(FrameSink* frameSink)
 	{
 		output = frameSink->CreateStream();
 	}
 
-	int inputSampleCount = 0;
+	StreamData* InputStream::DiscoverMetaData()
+	{
+		/*metaData = new StreamData();
+
+		AVRational* time_base = &timeBaseCorrectedByTicksPerFrame;
+		if (!timeBaseCorrectedByTicksPerFrame.num)
+		{
+			time_base = &stream->time_base;
+		}
+
+		metaData->timeBase.num = time_base->num;
+		metaData->timeBase.den = time_base->den;*/
+
+		AVRational overrideFrameRate;
+		overrideFrameRate.num = 0;
+
+		AVRational tb = overrideFrameRate.num ? av_inv_q(overrideFrameRate) : stream->time_base;
+		AVRational fr = overrideFrameRate;
+		if (!fr.num) fr = av_guess_frame_rate(format, stream, NULL);
+
+		StreamData* metaData = new StreamData();
+		metaData->timeBase = tb;
+		metaData->frameRate = fr;
+		return metaData;
+	}
 
 	void InputStream::DecodePacket(AVPacket *pkt)
 	{
@@ -122,16 +152,16 @@ namespace ffmpegcpp
 				frame->sample_aspect_ratio = stream->sample_aspect_ratio;
 			}
 
-			AVRational* time_base = &timeBaseCorrectedByTicksPerFrame;
-			if (!timeBaseCorrectedByTicksPerFrame.num)
+			// the meta data does not exist yet - we figure it out!
+			if (metaData == nullptr)
 			{
-				time_base = &stream->time_base;
+				metaData = DiscoverMetaData();
 			}
 
 			// push the frame to the next stage.
 			// The time_base is filled in in the codecContext after the first frame is decoded
 			// so we can fetch it from there.
-			output->WriteFrame(frame, time_base);
+			output->WriteFrame(frame, metaData);
 		}
 	}
 

source/ffmpeg-cpp/ffmpeg-cpp/Demuxing/InputStream.h

@@ -11,7 +11,7 @@ namespace ffmpegcpp
 
 	public:
 
-		InputStream(AVStream* stream);
+		InputStream(AVFormatContext* format, AVStream* stream);
 		~InputStream();
 
 		void Open();
@@ -33,11 +33,16 @@ namespace ffmpegcpp
 
 		AVRational timeBaseCorrectedByTicksPerFrame;
 
+		AVFormatContext* format;
 		AVStream* stream;
 
 		FrameSinkStream* output;
 
 		AVFrame* frame;
+
+		StreamData* metaData = nullptr;
+
+		StreamData* DiscoverMetaData();
 
 		void CleanUp();
 	};

source/ffmpeg-cpp/ffmpeg-cpp/Demuxing/StreamData.cpp

@@ -0,0 +1,12 @@
+#pragma once
+
+#include "ffmpeg.h"
+
+namespace ffmpegcpp
+{
+	struct StreamData
+	{
+		AVRational timeBase;
+		AVRational frameRate;
+	};
+}

source/ffmpeg-cpp/ffmpeg-cpp/Demuxing/StreamData.h

@@ -2,8 +2,8 @@
 
 namespace ffmpegcpp
 {
-	VideoInputStream::VideoInputStream(VideoFrameSink* frameSink, AVStream* stream)
-		: InputStream(stream)
+	VideoInputStream::VideoInputStream(VideoFrameSink* frameSink, AVFormatContext* format, AVStream* stream)
+		: InputStream(format, stream)
 	{
 		SetFrameSink(frameSink);
 	}

source/ffmpeg-cpp/ffmpeg-cpp/Demuxing/VideoInputStream.cpp

@@ -11,7 +11,7 @@ namespace ffmpegcpp
 
 	public:
 
-		VideoInputStream(VideoFrameSink* frameSink, AVStream* stream);
+		VideoInputStream(VideoFrameSink* frameSink, AVFormatContext* format, AVStream* stream);
 		~VideoInputStream();
 
 	protected:

source/ffmpeg-cpp/ffmpeg-cpp/Demuxing/VideoInputStream.h

@@ -26,7 +26,7 @@ namespace ffmpegcpp
 		finalBitRate = bitRate;
 	}
 
-	void AudioEncoder::OpenLazily(AVFrame* frame, AVRational* timeBase) 
+	void AudioEncoder::OpenLazily(AVFrame* frame, StreamData* metaData)
 	{
 		// configure the parameters for the codec based on the frame, our settings & defaults
 		int bitRate = finalBitRate;
@@ -92,12 +92,12 @@ namespace ffmpegcpp
 		return oneInputFrameSink->CreateStream();
 	}
 
-	void AudioEncoder::WriteFrame(int streamIndex, AVFrame* frame, AVRational* timeBase)
+	void AudioEncoder::WriteFrame(int streamIndex, AVFrame* frame, StreamData* metaData)
 	{
 		// if we haven't opened the codec yet, we do it now!
 		if (codec == nullptr)
 		{
-			OpenLazily(frame, timeBase);
+			OpenLazily(frame, metaData);
 		}
 
 		// set the PTS properly

source/ffmpeg-cpp/ffmpeg-cpp/Frame Sinks/AudioEncoder.cpp

@@ -21,7 +21,7 @@ namespace ffmpegcpp
 		virtual ~AudioEncoder();
 
 		FrameSinkStream* CreateStream();
-		void WriteFrame(int streamIndex, AVFrame* frame, AVRational* timeBase);
+		void WriteFrame(int streamIndex, AVFrame* frame, StreamData* metaData);
 		void Close(int streamIndex);
 
 		virtual void WriteConvertedFrame(AVFrame* frame);
@@ -30,7 +30,7 @@ namespace ffmpegcpp
 
 	private:
 
-		void OpenLazily(AVFrame* frame, AVRational* timeBase);
+		void OpenLazily(AVFrame* frame, StreamData* metaData);
 
 		void CleanUp();