When U.S. District Judge Denny Chin threw out the proposed Google Books Settlement earlier this year, he sent authors, publishers and Google back to the negotiating table in order to hammer out an agreement that would allow Google’s digitization efforts to move forward.

But it seems those negotiations are taking too long, and at a conference between the groups today, Judge Chin put pressure on those involved to finalize things, threatening to set a “tight discovery schedule” if things aren’t resolved when the group comes before him next on September 15.

Judge Chin’s frustrations over the delay aren’t surprising. The case has dragged on since the Authors Guild and Association of American Publishers each sued Google for its massive digitization efforts back in 2005. While the groups reached a settlement in 2008, Chin threw it out in March of this year, saying that it “would simply go too far.” In that ruling, Chin said that the settlement, as written, “would give Google a significant advantage over competitors, rewarding it for engaging in wholesale copying of copyrighted works without permission.”

Chin had argued that the settlement should have authors opt in to having their works digitized (and therefore searchable) by Google, rather than have them opt out, as the proposed settlement would have it.

And according to some indications from today’s meeting, an opt-in agreement is in the works. James Grimmelman reports in The Laboratorium that spokesperson Michael Boni, speaking for both Google and the plaintiffs, indicated that “the parties have been aiming for an opt-in settlement.’ What that might mean is not obvious. It could mean an actual opt-in settlement, one that binds only class members who send in claim forms. It could mean a settlement in which Google commits to an open-ended offer to all class members. It could mean a narrower, scanning-and-searching-only settlement, so that copyright owners can ‘opt in’ to book sales by striking their own individual deals with Google.”

Although all parties did tell the judge today that negotiations are moving forward, a resolution to the Google Books case doesn’t seem much closer. Judge Chin, however, seems determined to force things forward come September.