diff --git a/src/FFmpegReader.cpp b/src/FFmpegReader.cpp
index 84bbf853..5f54e5d7 100644
--- a/src/FFmpegReader.cpp
+++ b/src/FFmpegReader.cpp
@@ -486,7 +486,7 @@ tr1::shared_ptr<Frame> FFmpegReader::ReadStream(long int requested_frame)
 	// Minimum number of packets to process (for performance reasons)
 	int packets_processed = 0;
 	int minimum_packets = OPEN_MP_NUM_PROCESSORS;
-    int max_packets = 1024;
+    int max_packets = 4096;
 
 	// Set the number of threads in OpenMP
 	omp_set_num_threads(OPEN_MP_NUM_PROCESSORS);
diff --git a/src/Timeline.cpp b/src/Timeline.cpp
index 9b77f2c6..028610af 100644
--- a/src/Timeline.cpp
+++ b/src/Timeline.cpp
@@ -631,10 +631,6 @@ bool Timeline::isEqual(double a, double b)
 // Get an openshot::Frame object for a specific frame number of this reader.
 tr1::shared_ptr<Frame> Timeline::GetFrame(long int requested_frame) throw(ReaderClosed, OutOfBoundsFrame)
 {
-	// Check for open reader (or throw exception)
-	if (!is_open)
-		throw ReaderClosed("The Timeline is closed.  Call Open() before calling this method.", "");
-
 	// Adjust out of bounds frame number
 	if (requested_frame < 1)
 		requested_frame = 1;
@@ -653,6 +649,10 @@ tr1::shared_ptr<Frame> Timeline::GetFrame(long int requested_frame) throw(Reader
 		// Create a scoped lock, allowing only a single thread to run the following code at one time
 		const GenericScopedLock<CriticalSection> lock(getFrameCriticalSection);
 
+		// Check for open reader (or throw exception)
+		if (!is_open)
+			throw ReaderClosed("The Timeline is closed.  Call Open() before calling this method.", "");
+
 		// Check cache again (due to locking)
 		frame = final_cache->GetFrame(requested_frame);
 		if (frame) {
@@ -904,6 +904,9 @@ Json::Value Timeline::JsonValue() {
 // Load JSON string into this object
 void Timeline::SetJson(string value) throw(InvalidJSON) {
 
+	// Get lock (prevent getting frames while this happens)
+	const GenericScopedLock<CriticalSection> lock(getFrameCriticalSection);
+
 	// Parse JSON string into JSON objects
 	Json::Value root;
 	Json::Reader reader;
@@ -928,6 +931,7 @@ void Timeline::SetJson(string value) throw(InvalidJSON) {
 void Timeline::SetJsonValue(Json::Value root) throw(InvalidFile, ReaderClosed) {
 
 	// Close timeline before we do anything (this also removes all open and closing clips)
+	bool was_open = is_open;
 	Close();
 
 	// Set parent data
@@ -983,6 +987,10 @@ void Timeline::SetJsonValue(Json::Value root) throw(InvalidFile, ReaderClosed) {
 		info.duration = root["duration"].asDouble();
 		info.video_length = info.fps.ToFloat() * info.duration;
 	}
+
+	// Re-open if needed
+	if (was_open)
+		Open();
 }
 
 // Apply a special formatted JSON object, which represents a change to the timeline (insert, update, delete)