If you are looking for an online service which could help you to convert a Flash Video /FLV file or YouTube’s videos or etc. to MPEG4 (AVI,MOV,MP4,MP3,3GP), then vixy.net flv2mpeg4 can meet your requirement. You could submit a URL and it will download and convert to the video format then you could download the converted file. It is open source you can also get the source code directly. Then following is the URL if you are interested it why not have a try now?