diff --git a/aegisub/src/audio_controller.cpp b/aegisub/src/audio_controller.cpp
index 92dae866d..2453d5d38 100644
--- a/aegisub/src/audio_controller.cpp
+++ b/aegisub/src/audio_controller.cpp
@@ -92,7 +92,6 @@ class AudioMarkerProviderKeyframes : public AudioMarkerProvider {
 			keyframe_samples.push_back(AudioMarkerKeyframe(
 				controller->SamplesFromMilliseconds(vc->TimeAtFrame(raw_keyframes[i]))));
 		}
-		std::sort(keyframe_samples.begin(), keyframe_samples.end());
 		AnnounceMarkerMoved();
 	}
 
diff --git a/aegisub/src/mkv_wrap.cpp b/aegisub/src/mkv_wrap.cpp
index 980b3cb0c..e406f0c79 100644
--- a/aegisub/src/mkv_wrap.cpp
+++ b/aegisub/src/mkv_wrap.cpp
@@ -199,43 +199,17 @@ void MatroskaWrapper::Parse() {
 		}
 	}
 
-	// Copy raw
+	rawFrames.reserve(frames.size());
+	std::copy(frames.begin(), frames.end(), std::back_inserter(rawFrames));
+
+	// Process timecodes and keyframes
+	frames.sort();
+	int i = 0;
 	for (std::list<MkvFrame>::iterator cur=frames.begin();cur!=frames.end();cur++) {
-		rawFrames.push_back(*cur);
-	}
-
-	bool sortFirst = true;
-	if (sortFirst) {
-		// Process timecodes and keyframes
-		frames.sort();
-		MkvFrame curFrame(false,0,0);
-		int i = 0;
-		for (std::list<MkvFrame>::iterator cur=frames.begin();cur!=frames.end();cur++) {
-			curFrame = *cur;
-			if (curFrame.isKey) keyFrames.push_back(i);
-			bytePos.Add(curFrame.filePos);
-			timecodes.push_back(curFrame.time);
-			i++;
-		}
-	}
-
-	else {
-		// Process keyframes
-		MkvFrame curFrame(false,0,0);
-		int i = 0;
-		for (std::list<MkvFrame>::iterator cur=frames.begin();cur!=frames.end();cur++) {
-			curFrame = *cur;
-			if (curFrame.isKey) keyFrames.push_back(i);
-			bytePos.Add(curFrame.filePos);
-			i++;
-		}
-
-		// Process timecodes
-		frames.sort();
-		for (std::list<MkvFrame>::iterator cur=frames.begin();cur!=frames.end();cur++) {
-			curFrame = *cur;
-			timecodes.push_back(curFrame.time);
-		}
+		if (cur->isKey) keyFrames.push_back(i);
+		bytePos.Add(cur->filePos);
+		timecodes.push_back(cur->time);
+		i++;
 	}
 }
 
diff --git a/aegisub/src/video_slider.cpp b/aegisub/src/video_slider.cpp
index 379bc5e49..6828af349 100644
--- a/aegisub/src/video_slider.cpp
+++ b/aegisub/src/video_slider.cpp
@@ -346,26 +346,14 @@ void VideoSlider::OnKeyDown(wxKeyEvent &event) {
 		// Snap to keyframe
 		if (shift && !ctrl && !alt) {
 			if (direction != 0) {
-				// Prepare
-				int prevKey = 0;
-				int nextKey = max;
-				int keys = keyframes.size();
+				std::vector<int>::iterator pos = std::lower_bound(keyframes.begin(), keyframes.end(), val);
 
-				// Find previous keyframe
-				// This algorithm does unnecessary loops, but it ensures it works even if keyframes are out of order.
-				for (int i=0;i<keys;i++) {
-					int temp = keyframes[i];
-					if (temp < val && temp > prevKey) prevKey = temp;
-				}
+				if (direction < 0 && val != 0 && (pos == keyframes.end() || *pos == val))
+					--pos;
+				if (direction > 0 && pos != keyframes.end())
+					++pos;
 
-				// Find next keyframe
-				for (int i=0;i<keys;i++) {
-					int temp = keyframes[i];
-					if (temp > val && temp < nextKey) nextKey = temp;
-				}
-
-				if (direction == -1) VideoContext::Get()->JumpToFrame(prevKey);
-				if (direction == 1) VideoContext::Get()->JumpToFrame(nextKey);
+				VideoContext::Get()->JumpToFrame(pos == keyframes.end() ? max : *pos);
 				return;
 			}
 		}