diff --git a/aegisub/audio_display.cpp b/aegisub/audio_display.cpp
index 714f6da6a..36f720e71 100644
--- a/aegisub/audio_display.cpp
+++ b/aegisub/audio_display.cpp
@@ -2362,4 +2362,4 @@ void AudioDisplay::UpdateTimeEditCtrls() {
 	grid->editBox->StartTime->SetTime(curStartMS,true);
 	grid->editBox->EndTime->SetTime(curEndMS,true);
 	grid->editBox->Duration->SetTime(curEndMS-curStartMS,true);
-}
\ No newline at end of file
+}
diff --git a/aegisub/audio_provider_convert.cpp b/aegisub/audio_provider_convert.cpp
index f91c957b0..54e2eb8a4 100644
--- a/aegisub/audio_provider_convert.cpp
+++ b/aegisub/audio_provider_convert.cpp
@@ -34,9 +34,6 @@
 //
 
 
-#pragma once
-
-
 ///////////
 // Headers
 #include "audio_provider_convert.h"
diff --git a/aegisub/audio_provider_pcm.cpp b/aegisub/audio_provider_pcm.cpp
index 949b1ada5..b91430f81 100644
--- a/aegisub/audio_provider_pcm.cpp
+++ b/aegisub/audio_provider_pcm.cpp
@@ -119,7 +119,7 @@ public:
 		// Read header
 		file.Seek(0);
 		RIFFChunk header;
-		if (file.Read(&header, sizeof(header)) < sizeof(header)) throw _T("RIFF PCM WAV audio provider: file is too small to contain a RIFF header");
+		if (file.Read(&header, sizeof(header)) < (ssize_t) sizeof(header)) throw _T("RIFF PCM WAV audio provider: file is too small to contain a RIFF header");
 
 		// Check that it's good
 		if (strncmp(header.ch.type, "RIFF", 4)) throw _T("RIFF PCM WAV audio provider: File is not a RIFF file");
@@ -141,7 +141,7 @@ public:
 		while (data_left) {
 			file.Seek(filepos);
 			ChunkHeader ch;
-			if (file.Read(&ch, sizeof(ch)) < sizeof(ch)) break;
+			if (file.Read(&ch, sizeof(ch)) < (ssize_t) sizeof(ch)) break;
 
 			// Update counters
 			data_left -= sizeof(ch);
@@ -152,7 +152,7 @@ public:
 				got_fmt_header = true;
 
 				fmtChunk fmt;
-				if (file.Read(&fmt, sizeof(fmt)) < sizeof(fmt)) throw _T("RIFF PCM WAV audio provider: File ended before end of 'fmt ' chunk");
+				if (file.Read(&fmt, sizeof(fmt)) < (ssize_t) sizeof(fmt)) throw _T("RIFF PCM WAV audio provider: File ended before end of 'fmt ' chunk");
 
 				if (fmt.compression != 1) throw _T("RIFF PCM WAV audio provider: Can't use file, not PCM encoding");
 
diff --git a/aegisub/audio_spectrum.cpp b/aegisub/audio_spectrum.cpp
index 951ec1ebb..585ebd1bf 100644
--- a/aegisub/audio_spectrum.cpp
+++ b/aegisub/audio_spectrum.cpp
@@ -157,13 +157,6 @@ public:
 
 		unsigned int overlap_offset = line_length / overlaps * 2; // FIXME: the result seems weird/wrong without this factor 2, but why?
 
-		// Raw sample data
-		short *raw_sample_data = NULL;
-		float *sample_data = NULL;
-		// Real and imaginary components of the output
-		float *out_r = NULL;
-		float *out_i = NULL;
-
 		FFT fft; // Use FFTW instead? A wavelet?
 
 		for (unsigned int overlap = 0; overlap < overlaps; ++overlap) {
diff --git a/aegisub/auto4_ruby.h b/aegisub/auto4_ruby.h
index 8538b9352..1d67146bc 100644
--- a/aegisub/auto4_ruby.h
+++ b/aegisub/auto4_ruby.h
@@ -38,7 +38,9 @@
 #ifndef _AUTO4_RUBY_H
 #define _AUTO4_RUBY_H
 
+#ifdef _MSC_VER
 #pragma warning(disable: 4311 4312)
+#endif
 
 #include "auto4_base.h"
 #include <wx/thread.h>
diff --git a/aegisub/dialog_dummy_video.cpp b/aegisub/dialog_dummy_video.cpp
index fc11d74fc..d0a54cfe8 100644
--- a/aegisub/dialog_dummy_video.cpp
+++ b/aegisub/dialog_dummy_video.cpp
@@ -238,7 +238,7 @@ void DialogDummyVideo::OnLengthChange(wxCommandEvent &evt)
 void DialogDummyVideo::UpdateLengthDisplay()
 {
 	double fpsval;
-	int lengthval;
+	int lengthval = 0;
 	if (!length_display) return;
 	if ((fps->GetValue().ToDouble(&fpsval)) && (lengthval = length->GetValue()) && fpsval > 0 && lengthval > 0) {
 		int tt = int(lengthval / fpsval * 1000); // frames / (frames/seconds) * 1000 = milliseconds
diff --git a/aegisub/subtitle_format_dvd.cpp b/aegisub/subtitle_format_dvd.cpp
index f4fc67643..a1ab9579f 100644
--- a/aegisub/subtitle_format_dvd.cpp
+++ b/aegisub/subtitle_format_dvd.cpp
@@ -34,9 +34,6 @@
 //
 
 
-#pragma once
-
-
 ///////////
 // Headers
 #include "subtitle_format_dvd.h"
@@ -102,7 +99,9 @@ void DVDSubtitleFormat::GetSubPictureList(std::vector<SubPicture> &pics) {
 
 	// Write lines
 	int i;
+#ifdef _OPENMP
 	#pragma omp parallel for shared(diags,pics,provider) private(i)
+#endif
 	for (i=0;i<count;i++) {
 		// Dialogue
 		AssDialogue *current = diags[i];
@@ -111,7 +110,9 @@ void DVDSubtitleFormat::GetSubPictureList(std::vector<SubPicture> &pics) {
 		AegiVideoFrame dst;
 		dst.CopyFrom(srcFrame);
 		double time = (current->Start.GetMS()/1000.0 + current->End.GetMS()/1000.0)/2.0;
+#ifdef _OPENMP
 		#pragma omp critical
+#endif
 		{
 			provider->DrawSubtitles(dst,time);
 		}
@@ -132,7 +133,7 @@ void DVDSubtitleFormat::GetSubPictureList(std::vector<SubPicture> &pics) {
 		for (int y=h;--y>=0;) {
 			bool hasData = false;
 			int lineStartX = 0;
-			int lineEndX;
+			int lineEndX = 0;
 
 			// Scan line
 			for (int x=w;--x>=0;) {
diff --git a/aegisub/utils.cpp b/aegisub/utils.cpp
index 09baf800e..6c10dad99 100644
--- a/aegisub/utils.cpp
+++ b/aegisub/utils.cpp
@@ -285,13 +285,13 @@ void GetWordBoundaries(const wxString text,IntPairVector &results,int start,int
 /////////////////////
 // String to integer
 // wxString::ToLong() is slow and not as flexible
-int StringToInt(const wxString &str,size_t start,size_t end) {
+int StringToInt(const wxString &str,int start,int end) {
 	// Initialize to zero and get length if end set to -1
 	int sign = 1;
 	int value = 0;
 	if (end == -1) end = str.Length();
 
-	for (size_t pos=start;pos<end;pos++) {
+	for (int pos=start;pos<end;pos++) {
 		// Get value and check if it's a number
 		int val = (int)(str[pos]);
 		if (val == _T(' ') || val == _T('\t')) continue;
@@ -309,7 +309,7 @@ int StringToInt(const wxString &str,size_t start,size_t end) {
 
 /////////////////////////
 // String to fixed point
-int StringToFix(const wxString &str,size_t decimalPlaces,size_t start,size_t end) {
+int StringToFix(const wxString &str,size_t decimalPlaces,int start,int end) {
 	// Parts of the number
 	int sign = 1;
 	int major = 0;
@@ -319,7 +319,7 @@ int StringToFix(const wxString &str,size_t decimalPlaces,size_t start,size_t end
 	int *dst = &major;
 	size_t mCount = 0;
 
-	for (size_t pos=start;pos<end;pos++) {
+	for (int pos=start;pos<end;pos++) {
 		// Get value and check if it's a number
 		int val = (int)(str[pos]);
 		if (val == _T(' ') || val == _T('\t')) continue;
diff --git a/aegisub/utils.h b/aegisub/utils.h
index 6e759f437..45720e15f 100644
--- a/aegisub/utils.h
+++ b/aegisub/utils.h
@@ -68,8 +68,8 @@ wxString PrettySize(int bytes);
 wxMenuItem *AppendBitmapMenuItem (wxMenu* parentMenu,int id,wxString text,wxString help,wxBitmap bmp,int pos=-1);
 int SmallestPowerOf2(int x);
 void GetWordBoundaries(const wxString text,IntPairVector &results,int start=0,int end=-1);
-int StringToInt(const wxString &str,size_t start=0,size_t end=-1);
-int StringToFix(const wxString &str,size_t decimalPlaces,size_t start=0,size_t end=-1);
+int StringToInt(const wxString &str,int start=0,int end=-1);
+int StringToFix(const wxString &str,size_t decimalPlaces,int start=0,int end=-1);
 wxIcon BitmapToIcon(wxBitmap bmp);
 
 
diff --git a/aegisub/validators.cpp b/aegisub/validators.cpp
index b8bd82fcd..b1263494b 100644
--- a/aegisub/validators.cpp
+++ b/aegisub/validators.cpp
@@ -64,7 +64,9 @@ NumValidator::NumValidator(wxString* _valPtr,bool isfloat,bool issigned) {
 
 ////////////////////
 // Copy constructor
-NumValidator::NumValidator(const NumValidator &from) {
+NumValidator::NumValidator(const NumValidator &from)
+: wxValidator()
+{
 	valPtr = from.valPtr;
 	isFloat = from.isFloat;
 	isSigned = from.isSigned;
diff --git a/aegisub/video_context.cpp b/aegisub/video_context.cpp
index 41462436a..ddb5cbee4 100644
--- a/aegisub/video_context.cpp
+++ b/aegisub/video_context.cpp
@@ -308,7 +308,7 @@ void VideoContext::SetVideo(const wxString &filename) {
 			bool isAllKeyFrames = true;
 			for (unsigned int i=1; i<KeyFrames.GetCount(); i++) {
 				// Is the last keyframe not this keyframe -1?
-				if (KeyFrames[i-1] != (i-1)) {
+				if (KeyFrames[i-1] != (int)(i-1)) {
 					// It's not all keyframes, go ahead
 					isAllKeyFrames = false;
 					break;
diff --git a/aegisub/visual_tool_vector_clip.cpp b/aegisub/visual_tool_vector_clip.cpp
index 7cc7f8ce8..8cfcbd528 100644
--- a/aegisub/visual_tool_vector_clip.cpp
+++ b/aegisub/visual_tool_vector_clip.cpp
@@ -208,8 +208,8 @@ void VisualToolVectorClip::PopulateFeatureList() {
 		// First point
 		if (isFirst) {
 			isFirst = false;
-			feat.x = cur->p1.x;
-			feat.y = cur->p1.y;
+			feat.x = (int)cur->p1.x;
+			feat.y = (int)cur->p1.y;
 			feat.type = DRAG_SMALL_CIRCLE;
 			feat.value = i;
 			feat.value2 = 0;
@@ -218,8 +218,8 @@ void VisualToolVectorClip::PopulateFeatureList() {
 
 		// Line
 		if (cur->type == CURVE_LINE) {
-			feat.x = cur->p2.x;
-			feat.y = cur->p2.y;
+			feat.x = (int)cur->p2.x;
+			feat.y = (int)cur->p2.y;
 			feat.type = DRAG_SMALL_CIRCLE;
 			feat.value = i;
 			feat.value2 = 1;
@@ -232,22 +232,22 @@ void VisualToolVectorClip::PopulateFeatureList() {
 			int size = features.size();
 
 			// Control points
-			feat.x = cur->p2.x;
-			feat.y = cur->p2.y;
+			feat.x = (int)cur->p2.x;
+			feat.y = (int)cur->p2.y;
 			feat.value = i;
 			feat.value2 = 1;
 			feat.brother[0] = size-1;
 			feat.type = DRAG_SMALL_SQUARE;
 			features.push_back(feat);
-			feat.x = cur->p3.x;
-			feat.y = cur->p3.y;
+			feat.x = (int)cur->p3.x;
+			feat.y = (int)cur->p3.y;
 			feat.value2 = 2;
 			feat.brother[0] = size+2;
 			features.push_back(feat);
 
 			// End point
-			feat.x = cur->p4.x;
-			feat.y = cur->p4.y;
+			feat.x = (int)cur->p4.x;
+			feat.y = (int)cur->p4.y;
 			feat.type = DRAG_SMALL_CIRCLE;
 			feat.value2 = 3;
 			features.push_back(feat);