It is a script based video editor. The nice thing about it for me is every project is self documented and you can change anything you like in any order. Something that would be damn hard with most other apps.
Basics:
the scripts are avs files. They are nothing more than text files with a different extension and can be edited accordingly.
Avisynth is now hooked into your system and any time you try to open an avs file avisynth will step in and feed the newly tweaked video to your app of choice (be it encoder or viewer and near enough all of them will open a video using avisynth even if they do not outright support it).
Unlike many other open source apps avisynth has some serious documentation, I am not sure if it will work on your machine (you may have installed it to a different directory) but on mine it is:
file:///C:/Program%20Files/AviSynth%202.5/Docs/english/index.htm
First up you need to open your video, also know as source commands. There are three main methods although the last I suggest you leave until you know what is what.
the most basic one is avisource, it opens avi files and little else.
next up is directshowsource, generally speaking if your machine can view the video directshowsource can as well. The only problem is the framerate calculations are a bit off (not the fault of this app though) and if you need frame specific (it will likely not matter in terms of viewing mind) then you may have problems or you will have to define it yourself.
lastly is the external command ffmpegsource, ffmpeg is one of the most respected video playback pieces of software in existence and this filter has ffmpeg do the decoding. It can open just about everything that is not DRM afflicted and this filter allows you to open files using it and more importantly it is more accurate than directshowsource (helps if you need to target specific frame numbers).
Grab it and read about it here:
http://forum.doom9.org/showthread.php?t=127037
There are a few other filters but if these three do not work then you are probably doing something wrong. In all three cases you can either name your video on the spot or you can add a full path. On the spot means the script has to be in the same directory as the video, full path means the script can be anywhere but changing the path means changing the script.
A sidenote. While I said you can use those filters as a source when playing with DVDs I like to use DGMpgdec source filters, he also did some for the new "HD" formats.
http://neuron2.net/dgmpgdec/dgmpgdec.html
It is not a simple filter but an external program. It is very good though and most scene releases or the good anime groups will use it.
Now you can edit your video, you can do just about anything you can think of here including basic editing.
As you asked
trim is to get rid of frames, a note on trimming: many video encoders/formats require that you
crop is to crop the video
there are many resize filters (if downscaling use the inbuilt, upscaling under 2x consider the inbuilt and over 2x see the doom9 forums and the high end stuff there)
to add video to the end of each other you can use + as in directshowsource("video1.avi")+directshowsource("video2.avi")+directshowsource("video3.avi")
or you can use it by defining video as a letter/some other name
a=directshowsource("video1.avi")
b=directshowsource("video2.avi")
c=directshowsource("video3.avi")
a+b+c
This will give you what you want.
See the documentation for specifics and the formats required.
A note. If you have multiple videos you are making into one then you can target specific videos using object oriented programming, in avisynth you use a "." between commands to chain them together. In the a+b+c case above you could then trim a video and then "a" would be the original video trimmed down first.
You could also add it into the long chain version but it gets nasty to read then.
Finally you get your video into a form you want. It may well already be here but you can convert the colourspace (RGB, yv12, yuy2....) if your encoder requires it, you can dub the video if you have another audio source.
If you are using multiple sources you can tie them together if you have not already.
Here is a basic script I grabbed from my drive but I suggest you look at the very extensive documentation first. Note the # is used to comment the script and it will not parse anything after it.
a=directshowsource("100_0107.MOV").trim(110,200).killaudio().converttorgb32()
v=directshowsource("Queen - Bohemian Rhapsody.408 - .mp3", fps=10).DelayAudio(-244)
audiodub(a,v).trim(0,65)
reduceby2()#MipSmooth(preset = "movieLQ")
The script eventually made this video:
http://www.4shared.com/file/21492108/86398455/bird.html
