looking for advice on how to learn directshow and ffmpeg.i have compiled some projects available on the internet ,but i still can't quite understand ,especially how to syncronize audio and video ,is timestamp contained in the file container like avi, mpeg,or included somewhere else ,because i notice that rtp protocal aslo has time stamp in its packet.i am really confused with so much conception in my head(codecs ,time syncronization),can any one help me how to learn these stuff ,many thanks...