即时获取YouTube音频流

I am trying to get an audio stream (in mp3 format with fixed quality) from a YouTube video in PHP.

Notice that I cannot use FFMPEG and also i do not want to save the mp3 on my server, but I need only the audio stream (on the fly use).

Do you have any code or script? I have used many, but the half needs FFMPEG and the other saves the mp3 file in the server.

My plan is to hit on the browser:

http://host.com/process.php?url=<youtubeurl>

and get the audio stream in the page in variable that creating every time

&stream = ......;

It's not PHP, but we've open sourced a simple all-in-one node.js/CoffeeScript web app that can download a YouTube videos from a URL and then convert the video into an MP3 using ffmpeg.

github / demo / blog