AVSync drops incorrect packets to make A/V sync.

FilterDemuxer wraps origin Demuxer and Filter into a new Demuxer, when read this Demuxer filters will be called.

FixTime fixes incorrect packet timestamps.

WaitKeyFrame drops packets until first video key frame arrived.

Walltime makes packets reading speed as same as walltime, effect like ffmpeg -re option.

Filters type combines multiple Filters into one, ModifyPacket will be called in order.