A big refactor of the Open() method on Readers, and the constructor of Readers. All resource consuming code has been moved into the Open() methods, so the Clips and Timeline can control them better.

src/FFmpegReader.cpp

@@ -2,7 +2,7 @@
 
 using namespace openshot;
 
-FFmpegReader::FFmpegReader(string path) throw(InvalidFile, NoStreamsFound, InvalidCodec)
+FFmpegReader::FFmpegReader(string path)
 	: last_frame(0), is_seeking(0), seeking_pts(0), seeking_frame(0),
 	  audio_pts_offset(99999), video_pts_offset(99999), working_cache(12), final_cache(24), path(path),
 	  is_video_seek(true), check_interlace(false), check_fps(false), enable_seek(true),
@@ -13,12 +13,6 @@ FFmpegReader::FFmpegReader(string path) throw(InvalidFile, NoStreamsFound, Inval
 
 	// Initialize FFMpeg, and register all formats and codecs
 	av_register_all();
-
-	// Open the file (if possible)
-	Open();
-
-	// Get 1st frame
-	GetFrame(1);
 }
 
 // Init a collection of software rescalers (thread safe)
@@ -46,7 +40,7 @@ void FFmpegReader::RemoveScalers()
 	image_rescalers.clear();
 }
 
-void FFmpegReader::Open()
+void FFmpegReader::Open() throw(InvalidFile, NoStreamsFound, InvalidCodec)
 {
 	// Open reader if not already open
 	if (!is_open)
@@ -136,6 +130,9 @@ void FFmpegReader::Open()
 
 		// Mark as "open"
 		is_open = true;
+
+		// Get 1st frame
+		GetFrame(1);
 	}
 }
 
@@ -279,8 +276,12 @@ void FFmpegReader::UpdateVideoInfo()
 
 }
 
-Frame* FFmpegReader::GetFrame(int requested_frame)
+Frame* FFmpegReader::GetFrame(int requested_frame) throw(ReaderClosed)
 {
+	// Check for open reader (or throw exception)
+	if (!is_open)
+		throw ReaderClosed("The FFmpegReader is closed.  Call Open() before calling this method.", path);
+
 	// Check the cache for this frame
 	if (final_cache.Exists(requested_frame))
 		// Return the cached frame