You can do it in three ways
1.Use NSData length
ALAssetRepresentation *rep = [alasset defaultRepresentation];
Byte *buffer = (Byte*)malloc(rep.size);
NSError *error = nil;
NSUInteger buffered = [rep getBytes:buffer fromOffset:0.0 length:rep.size error:&error];
NSData *data = [NSData dataWithBytesNoCopy:buffer length:buffered freeWhenDone:YES];
NSLog(@"Size of video %d",data.length);
2.Make use of ALAssetRepresentationsize
3.Worst-Case Scenario: Use the videoPathURL
that points to the saved video file, retrieve it again using ALAsset
and caliculate the size.