I have more then 1000 videos that i want to use for radio over Shoutcast.
Recommend a software to batch demux audio from video files to mp3 or aac. Video are original formats for TV broadcasting so the quality of the sound is excellent.
As leftaroundabout said, use ffmpeg (or avconv - the one is forked off the other). It is command line based, which makes it useful for batch operations. On my Linux box the batch command would be something similar to:
for FILE in *.mp4 do ffmpeg -i $FILE $FILE.mp3 done
Use the -c:a copy option if you just want to strip away video and use the audio codec as-is.
I don't know how the loop would look in Windows.
I you don't want to use the command line, just google for some utility. There are probably hundreds.