Softgenlock: Active Stereo and GenLock for PC Cluster

Abstract

In this paper, we present SoftGenLock, an open source software that enables genlock and active stereo on commodity graphics cards. SoftGenLock is implemented on top of Linux. It does not require any hardware modification of the graphics card. Rather than to gain total control on signal generation, which would make the software deeply dependent on the graphics card specification, SoftGenLock applies continuous small modifications to converge and maintain genlocked video signals. To be properly synchronized with each video retrace, SoftGenLock is executed as a real-time task. The genlock signal is propagated along the different machines using the parallel port, a low latency device present on all PCs. It results in a software that only requires access to few specific registers on a graphics card: it can be ported with minimal effort on potentially any graphics card.