Arapahoe County Sheriff/AP Photo

Accused Aurora, Colo., theater shooter James Holmes appeared in court today where a judge set a preliminary hearing for January 7 that is expected to last several days.

Hundreds of people including witnesses, victims and families are expected to attend.

Prosecutors say part of the evidence presented at the preliminary hearing will include recordings of calls to 911 and approximately 30 hours of video from inside the Century 16 multiplex.

Holmes was in court for Wednesday's hearing, his brown hair slightly grown out from his last appearance and now wearing a full beard. He did not speak and sat quietly at the defense table in a maroon jumpsuit and shackles.

Both sides told judge William Sylvester that they are ready to proceed on January 7.

At a preliminary hearing, prosecutors must convince the judge there is enough evidence against Holmes to proceed to a trial. As part of that process, law enforcement investigators are expected to testify about details of the case that have never been revealed before.

The preliminary hearing will be held in the largest courtroom available in Arapahoe County Colorado, which holds about 100 people. Overflow crowds will be able to watch the proceeding on a video and audio feed in several rooms around the court complex, including a jury assembly room that has room for about 300 people.

Holmes is accused of murdering 12 people and wounding 58 when he allegedly opened fire at a midnight screening of the Batman film "The Dark Knight Rises". His defense team believes Holmes is mentally ill. He has not entered a plea.

Read our full coverage of the shootings.

The theater where the shooting occurred is set to reopen January 17.