If it's time, storage, and compute sensitive to generate it beforehand why on this green earth would you want to do it at stream runtime? Do you enjoy the thought of waiting 5-10 minutes for a stream to start or causing continual buffering problems during the stream? Also to my understanding the way it is built requires that the encoding be done for the entire length of the stream before any benefits are shown, so starting the process at stream launch would be less than useful even under the best circumstances. I think what you want to do is to sort your library into two, one you want to watch, and an archive. From there you can enable trickplay on just the "want to watch" library.