Filters in FFmpeg are inmplemented via libavfilter library. For optimal performance they are often used in filterchains and filtergraphs. with filtergraphs can be used the labeled links that can substitute an input in the filterchains that follows, a special [in] link label is created by default and denotes the input entered with -i option. Combining filters to filterchains and filtergraphs is more preferred than repeated processing that involves slight changes caused by compression algorithms.
The list of filters is in the 2nd chapter and is showed by: ffmpeg -filter video filters can be divided accourding to several criteria and the general classification is in the next table:
|Prefilters||used before enoding||contrast adjustment ,
scale (downsample, upsample)
|Intrafilters||used in encoding (usually part of a video codec)||deblock|
|Postfilters||used after encoding||deblock, deinterlace, dering|
More information about filters (FFmpeg Filters Documentation)