Ah, I'm sorry to hear about the looping issue. If you don't mind answering some questions, it would help me figure out what's going on. Do you have this issue with any of the other backgrounds? Or is it just the SP-CTRL video background? Is it a pure white flash, or just a brighter frame? What is your operating system and are you on the latest version of StimuWrite?
As for the soundscape suggestions I will definitely consider them!