Fixed crashes for Video with no content

code/FBXConverter.cpp

@@ -1499,7 +1499,7 @@ private:
             path.Set(tex->RelativeFilename());
 
             const Video* media = tex->Media();
-            if(media != 0) {
+            if(media != 0 && media->ContentLength() > 0) {
                 unsigned int index;
 
                 VideoMap::const_iterator it = textures_converted.find(media);

code/FBXDocument.h

@@ -701,7 +701,6 @@ public:
     uint8_t* RelinquishContent() {
         uint8_t* ptr = content;
         content = 0;
-        contentLength = 0;
         return ptr;
     }