MediaJoin 

Easily join / combine all popular audio and video formats into a single merged file. Formats supported include MP3, WMA, WAV, OGG, AVI, MPEG-1, MPEG-2, and WMV. Optionally include audio tag information for the combined output audio file.
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JFuse AVI, MPEG Joiner / Mpeg Splitter 

Joins or splits media files. Merge small movie files together so they can be viewed as one clip.
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