diff --git a/webrtc/api/objc/RTCDataChannel.h b/webrtc/api/objc/RTCDataChannel.h
index 8ab4b34be7..43f5767702 100644
--- a/webrtc/api/objc/RTCDataChannel.h
+++ b/webrtc/api/objc/RTCDataChannel.h
@@ -46,7 +46,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /** The data channel's |bufferedAmount| changed. */
 - (void)dataChannel:(RTCDataChannel *)dataChannel
-    didChangeBufferedAmount:(NSUInteger)amount;
+    didChangeBufferedAmount:(uint64_t)amount;
 
 @end
 
diff --git a/webrtc/api/objc/RTCDataChannel.mm b/webrtc/api/objc/RTCDataChannel.mm
index 98599058ee..4be3a227be 100644
--- a/webrtc/api/objc/RTCDataChannel.mm
+++ b/webrtc/api/objc/RTCDataChannel.mm
@@ -34,8 +34,8 @@ class DataChannelDelegateAdapter : public DataChannelObserver {
 
   void OnBufferedAmountChange(uint64_t previousAmount) override {
     id<RTCDataChannelDelegate> delegate = channel_.delegate;
-    if ([delegate
-            respondsToSelector:@selector(channel:didChangeBufferedAmount:)]) {
+    SEL sel = @selector(dataChannel:didChangeBufferedAmount:);
+    if ([delegate respondsToSelector:sel]) {
       [delegate dataChannel:channel_ didChangeBufferedAmount:previousAmount];
     }
   }
diff --git a/webrtc/api/objc/RTCIceCandidate.h b/webrtc/api/objc/RTCIceCandidate.h
index 41ea69e991..e521ae04f6 100644
--- a/webrtc/api/objc/RTCIceCandidate.h
+++ b/webrtc/api/objc/RTCIceCandidate.h
@@ -24,7 +24,7 @@ NS_ASSUME_NONNULL_BEGIN
  * The index (starting at zero) of the media description this candidate is
  * associated with in the SDP.
  */
-@property(nonatomic, readonly) NSInteger sdpMLineIndex;
+@property(nonatomic, readonly) int sdpMLineIndex;
 
 /** The SDP string for this candidate. */
 @property(nonatomic, readonly) NSString *sdp;
@@ -35,7 +35,7 @@ NS_ASSUME_NONNULL_BEGIN
  * Initialize an RTCIceCandidate from SDP.
  */
 - (instancetype)initWithSdp:(NSString *)sdp
-              sdpMLineIndex:(NSInteger)sdpMLineIndex
+              sdpMLineIndex:(int)sdpMLineIndex
                      sdpMid:(nullable NSString *)sdpMid
     NS_DESIGNATED_INITIALIZER;
 
diff --git a/webrtc/api/objc/RTCIceCandidate.mm b/webrtc/api/objc/RTCIceCandidate.mm
index b0b8abc8ca..ecc128f8b2 100644
--- a/webrtc/api/objc/RTCIceCandidate.mm
+++ b/webrtc/api/objc/RTCIceCandidate.mm
@@ -21,7 +21,7 @@
 @synthesize sdp = _sdp;
 
 - (instancetype)initWithSdp:(NSString *)sdp
-              sdpMLineIndex:(NSInteger)sdpMLineIndex
+              sdpMLineIndex:(int)sdpMLineIndex
                      sdpMid:(NSString *)sdpMid {
   NSParameterAssert(sdp.length);
   if (self = [super init]) {
@@ -33,9 +33,9 @@
 }
 
 - (NSString *)description {
-  return [NSString stringWithFormat:@"RTCIceCandidate:\n%@\n%ld\n%@",
+  return [NSString stringWithFormat:@"RTCIceCandidate:\n%@\n%d\n%@",
                                     _sdpMid,
-                                    (long)_sdpMLineIndex,
+                                    _sdpMLineIndex,
                                     _sdp];
 }
 
diff --git a/webrtc/api/objc/RTCOpenGLVideoRenderer.mm b/webrtc/api/objc/RTCOpenGLVideoRenderer.mm
index 56a6431ffa..b4a7c7b13a 100644
--- a/webrtc/api/objc/RTCOpenGLVideoRenderer.mm
+++ b/webrtc/api/objc/RTCOpenGLVideoRenderer.mm
@@ -148,7 +148,7 @@ static const GLsizei kNumTextures = 3 * kNumTextureSets;
   NSOpenGLContext *_context;
 #endif
   BOOL _isInitialized;
-  NSUInteger _currentTextureSet;
+  GLint _currentTextureSet;
   // Handles for OpenGL constructs.
   GLuint _textures[kNumTextures];
   GLuint _program;
@@ -313,10 +313,10 @@ static const GLsizei kNumTextures = 3 * kNumTextureSets;
       frame.chromaHeight == _lastDrawnFrame.chromaHeight) {
     return YES;
   }
-  GLsizei lumaWidth = frame.width;
-  GLsizei lumaHeight = frame.height;
-  GLsizei chromaWidth = frame.chromaWidth;
-  GLsizei chromaHeight = frame.chromaHeight;
+  GLsizei lumaWidth = static_cast<GLsizei>(frame.width);
+  GLsizei lumaHeight = static_cast<GLsizei>(frame.height);
+  GLsizei chromaWidth = static_cast<GLsizei>(frame.chromaWidth);
+  GLsizei chromaHeight = static_cast<GLsizei>(frame.chromaHeight);
   for (GLint i = 0; i < kNumTextureSets; i++) {
     glActiveTexture(GL_TEXTURE0 + i * 3);
     glTexImage2D(GL_TEXTURE_2D,
@@ -361,11 +361,11 @@ static const GLsizei kNumTextures = 3 * kNumTextureSets;
 
 - (void)uploadPlane:(const uint8_t *)plane
             sampler:(GLint)sampler
-             offset:(NSUInteger)offset
+             offset:(GLint)offset
               width:(size_t)width
              height:(size_t)height
              stride:(int32_t)stride {
-  glActiveTexture(GL_TEXTURE0 + offset);
+  glActiveTexture(static_cast<GLenum>(GL_TEXTURE0 + offset));
   // When setting texture sampler uniforms, the texture index is used not
   // the texture handle.
   glUniform1i(sampler, offset);
@@ -382,8 +382,8 @@ static const GLsizei kNumTextures = 3 * kNumTextureSets;
       glTexImage2D(GL_TEXTURE_2D,
                    0,
                    RTC_PIXEL_FORMAT,
-                   width,
-                   height,
+                   static_cast<GLsizei>(width),
+                   static_cast<GLsizei>(height),
                    0,
                    RTC_PIXEL_FORMAT,
                    GL_UNSIGNED_BYTE,
@@ -403,8 +403,8 @@ static const GLsizei kNumTextures = 3 * kNumTextureSets;
   glTexImage2D(GL_TEXTURE_2D,
                0,
                RTC_PIXEL_FORMAT,
-               width,
-               height,
+               static_cast<GLsizei>(width),
+               static_cast<GLsizei>(height),
                0,
                RTC_PIXEL_FORMAT,
                GL_UNSIGNED_BYTE,
@@ -412,7 +412,7 @@ static const GLsizei kNumTextures = 3 * kNumTextureSets;
 }
 
 - (BOOL)updateTextureDataForFrame:(RTCVideoFrame *)frame {
-  NSUInteger textureOffset = _currentTextureSet * 3;
+  GLint textureOffset = _currentTextureSet * 3;
   NSAssert(textureOffset + 3 <= kNumTextures, @"invalid offset");
 
   [self uploadPlane:frame.yPlane