How can I create links like this?

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Hello, I have a YouTube MP3 search script where only the links are a bit messy, for example: site.com/rihanna_mp3_download/dwqWQDswq(this was a YouTube video). It should be: site.com/5485/rihanna_mp3_download.html. I tried with .htaccess but it didn't work; I have no knowledge of MySQL to do this I will provide the MP3 search script to whoever does it.