"So there is no negotiation going on with all the other putative infringers because there have been no other lawsuits filed."
Your comment made me think there must be a way to search all U.S. districts simultaneously for any litigation involving e.Digital. I found such a search engine on PACER and when I typed in e.Digital, the only case found was the Vivitar case in eastern TX.
Was the digEcor case not identified because they are defendants, not plaintiffs? I would think all cases involving e.Digital would make the list. I'll contact PACER and ask the question.