How does the number of threads affect quality?
x264 implements threading with two models. The first is Avisynth input threading, and the second is parallel frames encoding. • Threaded Avisynth input: If the input is an .avs script, this setting will tell x264 to decode the avs in its own thread. This is especially useful for CPU intensive scripts, but also gives a slight advantage for even the fastest script. In MeGUI, this option is always on as it cannot reduce encoding speed nor quality. • Parallel frames encoding: The parallel frames encoding method was introduced in recent x264 revisions and is similar to the Xvid 1.2 implementation of multithreaded encoding. It is more efficient in both speed and final quality than the previously used slicing method implementation. This option is in MeGUI’s x264 codec config. The commandline switch is –threads n.
