diff --git a/libaegisub/audio/provider.cpp b/libaegisub/audio/provider.cpp
index 3c027470b..78d3facc2 100644
--- a/libaegisub/audio/provider.cpp
+++ b/libaegisub/audio/provider.cpp
@@ -31,7 +31,7 @@ void AudioProvider::GetAudioWithVolume(void *buf, int64_t start, int64_t count,
 
 	auto buffer = static_cast<int16_t *>(buf);
 	for (size_t i = 0; i < (size_t)count; ++i)
-		buffer[i] = util::mid<int>(-0x8000, buffer[i] * volume + 0.5, 0x7FFF);
+		buffer[i] = util::mid(-0x8000, static_cast<int>(buffer[i] * volume + 0.5), 0x7FFF);
 }
 
 void AudioProvider::ZeroFill(void *buf, int64_t count) const {
diff --git a/libaegisub/audio/provider_convert.cpp b/libaegisub/audio/provider_convert.cpp
index 1de536643..b45d8a852 100644
--- a/libaegisub/audio/provider_convert.cpp
+++ b/libaegisub/audio/provider_convert.cpp
@@ -39,7 +39,10 @@ public:
 		bytes_per_sample = sizeof(Target);
 	}
 
-	void FillBuffer(void *buf, int64_t start, int64_t count) const override {
+	void FillBuffer(void *buf, int64_t start, int64_t count64) const override {
+		auto count = static_cast<size_t>(count64);
+		assert(count == count64);
+
 		src_buf.resize(count * src_bytes_per_sample * channels);
 		source->GetAudio(src_buf.data(), start, count);
 
@@ -60,9 +63,9 @@ public:
 			}
 
 			if (static_cast<size_t>(src_bytes_per_sample) > sizeof(Target))
-				sample /= 1 << (src_bytes_per_sample - sizeof(Target)) * 8;
+				sample /= 1LL << (src_bytes_per_sample - sizeof(Target)) * 8;
 			else if (static_cast<size_t>(src_bytes_per_sample) < sizeof(Target))
-				sample *=  1 << (sizeof(Target) - src_bytes_per_sample ) * 8;
+				sample *=  1LL << (sizeof(Target) - src_bytes_per_sample ) * 8;
 
 			dest[i] = static_cast<Target>(sample);
 		}
@@ -80,7 +83,10 @@ public:
 		float_samples = false;
 	}
 
-	void FillBuffer(void *buf, int64_t start, int64_t count) const override {
+	void FillBuffer(void *buf, int64_t start, int64_t count64) const override {
+		auto count = static_cast<size_t>(count64);
+		assert(count == count64);
+
 		src_buf.resize(count * channels);
 		source->GetAudio(&src_buf[0], start, count);
 
@@ -111,7 +117,10 @@ public:
 		channels = 1;
 	}
 
-	void FillBuffer(void *buf, int64_t start, int64_t count) const override {
+	void FillBuffer(void *buf, int64_t start, int64_t count64) const override {
+		auto count = static_cast<size_t>(count64);
+		assert(count == count64);
+
 		src_buf.resize(count * src_channels);
 		source->GetAudio(&src_buf[0], start, count);
 
diff --git a/libaegisub/audio/provider_dummy.cpp b/libaegisub/audio/provider_dummy.cpp
index 7c11b325c..c068d3b4b 100644
--- a/libaegisub/audio/provider_dummy.cpp
+++ b/libaegisub/audio/provider_dummy.cpp
@@ -52,11 +52,11 @@ class DummyAudioProvider final : public AudioProvider {
 		if (noise) {
 			std::default_random_engine e;
 			std::uniform_int_distribution<int16_t> uniform_dist(-5000, 5000);
-			for (size_t i = 0; i < count; ++i)
+			for (int64_t i = 0; i < count; ++i)
 				static_cast<short *>(buf)[i] = uniform_dist(e);
 		}
 		else
-			memset(buf, 0, count * bytes_per_sample);
+			memset(buf, 0, static_cast<size_t>(count) * bytes_per_sample);
 	}
 
 public:
diff --git a/libaegisub/lua/modules/lpeg.c b/libaegisub/lua/modules/lpeg.c
index d5c426082..8d67335ab 100644
--- a/libaegisub/lua/modules/lpeg.c
+++ b/libaegisub/lua/modules/lpeg.c
@@ -1200,7 +1200,7 @@ static Instruction *fix_l (lua_State *L, int t) {
   }
   lua_pushvalue(L, base + 2);  /* get initial rule */
   lua_gettable(L, base + 1);  /* get its position in postions table */
-  i = lua_tonumber(L, -1);  /* convert to number */
+  i = lua_tointeger(L, -1);  /* convert to number */
   lua_pop(L, 1);
   if (i == 0)  /* is it defined? */
     luaL_error(L, "initial rule not defined in given grammar");