AVS Editor
License Agreement
NO COMMERCIAL USE: This License Agreement grants our community members the right to use the Software downloaded from DivX Labs for personal use only in order to evaluate and provide feedback about it to DivX, Inc. Commercial use of the Software or of the work products resulting from its use is not permitted under the Terms of Use of DivX Labs.- To read the full Terms of Use please visit the Terms of Use page.
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I read the excellent guide "DivX H.264 Encoder Alpha 1 & Tutorial" and I want to contribute by pointing out a very good editor for avs files called AvsP. It allows not only to edit scripts with powerful options like function completion, but it also has a preview that allows to view immediately changes to the script.
I think is better than using Notepad and VirtualDub.
It can be found at http://avisynth.org/qwerpoi/