added a frame count to the stream info

Author: Raveler

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

@@ -28,23 +28,6 @@ namespace ffmpegcpp
 		}
 
 		codecContext->framerate = stream->avg_frame_rate;
-	}
-
-	InputStream::~InputStream()
-	{
-		CleanUp();
-	}
-
-	void InputStream::ConfigureCodecContext()
-	{
-		// does nothing by default
-	}
-
-	void InputStream::Open(FrameSink* frameSink)
-	{
-		output = frameSink->CreateStream();
-
-		const AVCodec* codec = codecContext->codec;
 
 		// Copy codec parameters from input stream to output codec context
 		int ret;
@@ -76,6 +59,21 @@ namespace ffmpegcpp
 		}
 	}
 
+	InputStream::~InputStream()
+	{
+		CleanUp();
+	}
+
+	void InputStream::ConfigureCodecContext()
+	{
+		// does nothing by default
+	}
+
+	void InputStream::Open(FrameSink* frameSink)
+	{
+		output = frameSink->CreateStream();
+	}
+
 	void InputStream::CleanUp()
 	{
 		if (codecContext != nullptr)
@@ -158,13 +156,26 @@ namespace ffmpegcpp
 			// 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, metaData);
+			if (output == nullptr)
+			{
+				// No frame sink specified - just release the frame again.
+			}
+			else
+			{
+				output->WriteFrame(frame, metaData);
+			}
+			++nFramesProcessed;
 		}
 	}
 
+	int InputStream::GetFramesProcessed()
+	{
+		return nFramesProcessed;
+	}
+
 	void InputStream::Close()
 	{
-		output->Close();
+		if (output != nullptr) output->Close();
 	}
 
 	bool InputStream::IsPrimed()

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

@@ -21,6 +21,7 @@ namespace ffmpegcpp
 		void Close();
 
 		bool IsPrimed();
+		int GetFramesProcessed();
 
 		virtual void AddStreamInfo(ContainerInfo* info) = 0;
 
@@ -41,14 +42,15 @@ namespace ffmpegcpp
 
 		AVRational timeBaseCorrectedByTicksPerFrame;
 
-
-		FrameSinkStream* output;
+		FrameSinkStream* output = nullptr;
 
 		AVFrame* frame;
 
 		StreamData* metaData = nullptr;
 
 		StreamData* DiscoverMetaData();
+
+		int nFramesProcessed = 0;
 
 		void CleanUp();
 

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

@@ -22,6 +22,8 @@ namespace ffmpegcpp
 	{
 		VideoStreamInfo info;
 
+		info.id = stream->id - 1; // starts counting from 1!
+
 		AVRational overrideFrameRate;
 		overrideFrameRate.num = 0;
 

source/ffmpeg-cpp/ffmpeg-cpp/Sources/Demuxer.cpp

@@ -182,6 +182,10 @@ namespace ffmpegcpp
 		// already exists
 		if (inputStreams[streamIndex] != nullptr) return inputStreams[streamIndex];
 
+		// The stream doesn't exist but we already processed all our frames, so it makes no sense
+		// to add it anymore.
+		if (IsDone()) throw new FFmpegException("Demuxer already fully processed... you cannot use it anymore.");
+
 		AVStream* stream = containerContext->streams[streamIndex];
 		AVCodec* codec = CodecDeducer::DeduceDecoder(stream->codecpar->codec_id);
 		if (codec == nullptr) return nullptr; // no codec found - we can't really do anything with this stream!
@@ -303,4 +307,22 @@ namespace ffmpegcpp
 
 		return info;
 	}
+
+	int Demuxer::GetFrameCount(int streamId)
+	{
+		// Make sure all streams exist, so we can query them later.
+		for (int i = 0; i < containerContext->nb_streams; ++i)
+		{
+			GetInputStream(i);
+		}
+
+		// Process the entire container so we can know how many frames are in each 
+		while (!IsDone())
+		{
+			Step();
+		}
+
+		// Return the right stream's frame count.
+		return GetInputStream(streamId)->GetFramesProcessed();
+	}
 }

source/ffmpeg-cpp/ffmpeg-cpp/Sources/Demuxer.h

@@ -30,6 +30,7 @@ namespace ffmpegcpp
 		virtual void Step();
 
 		ContainerInfo GetInfo();
+		int GetFrameCount(int streamId);
 
 	private:
 

source/ffmpeg-cpp/print_info/print_info.cpp

@@ -30,6 +30,7 @@ int main()
 				<< ", bit rate " << stream.bitRate << "kb/s"
 				<< ", fps " << ((float)stream.frameRate.num / (float)stream.frameRate.den)
 				<< ", time base " << stream.timeBase.num  << "/" << stream.timeBase.den
+				<< ", " << demuxer->GetFrameCount(stream.id) << " frames"
 				<< endl;
 		}