The post-processing algorithm consists of the deblocking and the deringing filters. Post-processing is a CPU-intensive process, which sometimes takes longer than decoding. You may not want to post-process, especially if you prefer the un-post-processed image, or if your Mac is not powerful enough. To cater to user's post-processing preferences, 6 different levels of post-processing have been defined. At the minimum (level 0), no post-processing algorithm is used; at the maximum (level 6), every clever algorithm is tried to enhance the appearance of your frames.
To permit to adopt the amount of post-processing used to the user subjective preferences, 10 different levels of post-processing has been defined. At the minimum level (level 0) any post-processing algorithm is used, at the maximum level (level 6) every clever algorithm is adopted to make your frames look better.
The human eye is less sensitive to the chrominance components of the video signal and more sensitive to the luminance components. For this reason, only the luminance plane is processed at lower post-processing levels (level 1, 2 and 3), while higher levels (levels 4, 5, and 6) activate the same algorithms on the chrominance planes. The post-processing algorithms used are activated in the following order: deblocking horizontal, deblocking vertical, and deringing.
