diff --git a/SDAVAssetExportSession.m b/SDAVAssetExportSession.m
index e99993b..c368e20 100755
--- a/SDAVAssetExportSession.m
+++ b/SDAVAssetExportSession.m
@@ -305,11 +305,19 @@ - (AVMutableVideoComposition *)buildDefaultVideoComposition
         trackFrameRate = 30;
     }
 
-	videoComposition.frameDuration = CMTimeMake(1, trackFrameRate);
-	CGSize targetSize = CGSizeMake([self.videoSettings[AVVideoWidthKey] floatValue], [self.videoSettings[AVVideoHeightKey] floatValue]);
-	CGSize naturalSize = [videoTrack naturalSize];
-	CGAffineTransform transform = videoTrack.preferredTransform;
-	// Workaround radar 31928389, see https://github.com/rs/SDAVAssetExportSession/pull/70 for more info
+    videoComposition.frameDuration = CMTimeMake(1, trackFrameRate);
+    CGSize targetSize = CGSizeMake([self.videoSettings[AVVideoWidthKey] floatValue], [self.videoSettings[AVVideoHeightKey] floatValue]);
+    CGSize naturalSize = [videoTrack naturalSize];
+    CGAffineTransform transform = videoTrack.preferredTransform;
+	
+    // Fix for mp4 video black screen with audio, see https://github.com/rs/SDAVAssetExportSession/issues/79 for more info
+    CGRect rect = {{0, 0}, naturalSize};
+    CGRect transformedRect = CGRectApplyAffineTransform(rect, transform);
+    // transformedRect should have origin at 0 if correct; otherwise add offset to correct it
+    transform.tx -= transformedRect.origin.x;
+    transform.ty -= transformedRect.origin.y;
+    
+    // Workaround radar 31928389, see https://github.com/rs/SDAVAssetExportSession/pull/70 for more info
 	if (transform.ty == -560) {
 		transform.ty = 0;
 	}