i am currently working on .net application which contains one audio & video file.
audio file is split as in to small section as per database entries. then we have to merge this files on video file at specific positions.we what something like windows movie maker
it will be nice if someone suggest some .net based sdk for this.
You can use ffmpeg for this purpose. But you will need a .net wrapper to make it usable in C#.
You can use ffmpeg-sharp or SolidFFMpeg. its a a wrapper library over the FFmpeg multimedia suite that provides easy to use wrappers for use in C#.
Datastead Software's TVideoGrabber Video SDK has this feature.
"join several video clips and/or audio clips into a single one, in full or by specifying respective start times and end times"
http://www.datastead.com/products/tvideograbber/features.html
The engine behind Windows Movie Maker is DirectShow Editing Services. You can use it via DirectShow.NET.