Abstract: Audio-visual systems including a motion picture film projector and a tape player, the film having optical cues and program reference notches for stopping film advancement, and the tape having start cues for starting film advancement. The optical stop cues are detected dynamically and with cue length discrimination. A program select control causes the system to search for a program reference notch and to ignore optical stop cue until the notch is detected. Other features include a pause-run control, a variable frame rate control with a single-frame advance option, and remote controls. Optical stop cue detection systems include a light transmissive system, a light reflective system, a polarized light system, and a colored light system.

Abstract: In an endless-roll film cartridge the problem of cyclical variation in film stepping distance (tick-tocking) is overcome by isolating the inertia of the coil of film from the segment of the film loop engaged by the drive claw, and by storing energy in the film segment returning to the coil each time the film is advanced by the claw and then releasing the energy to move the coil preparatory to the next advancement of the film by the claw. Variable blends provide compliance in the film path at opposite ends of the segment engaged by the claw, one of the bends being controlled by a pocket in a guide defining the path of the film segment returning to the coil.