iTunes U: How can I extract audio from video lectures?

Question

I download lots of lectures from iTunes U. The problem is, they usually come with video and there is no audio-only version for many.

How can I, using any software available for Snow Leopard, free or paid, extract the audio from a series of video files and end up with a series of audio files?

Any ideas?

Answer 1

Please try it with VLC, see Extract Audio in the Videolan wiki.

Answer 2

I suggest using Max or ffmpegx, which is a GUI for ffmpeg.

You can also use ffmpeg from the shell:

for f in *.mp4; do ffmpeg -i "$f" -vn -c copy "${f%mp4}m4a"; done

-vn (video none) removes video streams and -c copy disables re-encoding the audio. You can install ffmpeg with brew install ffmpeg after installing Homebrew.

Answer 3

You can import the clip into iMovie, then export it as an AIF audio file using the iMovie Share menu's Quicktime export feature. Then you can import the AIF file into iTunes. Once it's in iTunes, you can create a much more compact MP3 version. All rather cumbersome. Too bad iTunes U doesn't just upload audio versions of all the lectures. The video files are big and unwieldy and difficult to use on an iPod.

Answer 4

Old question, but one you can do that nobody mentioned is, download a bunch of Video Lectures using Itunes U.

Add the selections to a Playlist in iTunes.

Right click the Playlist and select Burn Playlist to Disc:

There will be Disc Formats : Audio CD. and MP3 Cd.

selecting either of those options will strip just the audio out of the disc. Selecting Mp3 CD will give you the list of Mp3 files you were after.

The only catch is you have to write them to disc first. But it requires no third party tools or downloads and if your car doesn't have an easy audio hookup for the iPhone you can play them right off the CD.

Answer 5

I use AudioHijack Pro it costs money though. I can rip audio from DVDs and Internet streams.