I use to listen music sessions on vimeo.com, normally session of the guys of Dace Tripping TV, but I have two big problems.

The first problem is that I must use the flash player on the web, and I don't like it because we all know that Flash is a pice of shit (and is more shitty if you are running Flash on Linux). 32% of CPU usage (normally I have a 2-3% of CPU usage) and 71ºC of temperature in my processor (50ºC is the usual). For listening music. Bah.

The other problem is that sometimes I really like the session. And every time I want to listen it again I have to open a web browser, download 700MiB for 45 minutes of video and... I'm just interested in the audio!!!

A solution to both problems can be download the video with the Firefox plugin "Flash and Video Download 1.10". I'm not going to explain how to download a video with this plugin because it's dead easy.

You will end up with an MP4 file in you computer. You can reproduce this video using VLC using 9% of CPU. And that's fine. But if you are just interested in the music, you can extract the audio from the video with these commands:

sudo aptitude install ffmpeg  -y

ffmpeg -i vimeo_video-hd.mp4 -f mp3 -ab 192k -vn output_file_audio.mp3

If the file is a FLV you can try executing:

ffmpeg -i 34792213-hd.flv  -ar 44100 -ab 160k -ac 2 extracted_audio_filename.mp3

And that's all. Now you can play you audio file with moc or cmus or you favourite music player ;)

Note: I don't really know the legality of download copyrighted files and extract the audio of them. Take care and check you local laws about that.

[Edit] Interesting link: http://go2linux.garron.me/trim-cut-join-split-mp3-files-with-linux