Thanks for the extremely fast response. I completely missed the difference in the subfile_open of the two streams in my first glance. So it should just be a simple exercise of replicating big with fdopen.

If I really want to strive for the speed in stream I could see if Android supports any method of FILE* to fstream. How much of an improvement do you think there is? It's Android, so linux, if the improvement only lies in Win.

Thanks again!