Service to make an audio podcast from a video one?

Question

1. Video podcast
2. ???
3. Audio only mp3 player

I'm looking for somewhere which will extract audio from video, but instead of a single file, for an on going video podcast.

I would most like a website which would suck in the RSS and spit out an RSS (I'm thinking of something like Feedburner), though would settle for something on my own machine.

If it must be on my machine, it should be quick, transparent, and automatic when I download each episode.

What would you use?

Edit: I'm on an Ubuntu 8.04 machine; so running ffmpeg is no problem; however, I'm looking for automation and feed awareness.

Here's my use case: I want to listen to lectures at Google Video, or Structure and Interpretation of Computer Programs. These videos come out fairly often, so anything that's needed to be done manually will also be done fairly often.

Here's one approach I'd thought of:

• download the RSS
• parse the RSS for enclosures,
• download the enclosures, keeping a track what has already been downloaded previously
• transcode the files, but not the ones done already
• reconstruct an RSS with the audio files, remembering to change the metadata.
• schedule to be run periodically
• point podcatcher at new RSS feed.

I also liked the approach of gPodder of using a post-download script.

I wish the Lazy Web still worked.

Answer 1

How to extract audio from video to MP3:

http://www.dvdvideosoft.com/guides/dvd/extract-audio-from-video-to-mp3.htm

How to Convert a Video Podcast to Audio Only:

http://www.legalandrew.com/2007/03/10/how-to-convert-a-video-podcast-to-audio-only/

Answer 2

When you edit your video, doesn't your editor provide you an option to split out the audio?

Answer 3

What platform is your own machine? What format is the video podcast?

You could possibly get Handbrake to do this (Windows, Linux and Mac), I don't know if it's scriptable at all but I think it can be used to separate audio and video.

edit: There is a commandline interface for Handbrake, but it appears I was wrong about it accepting non-DVD input. On the Mac I'd probably rig up something with Applescript and QuickTime - what platform are you on?

Answer 4

You could automate this using the open source command line tool ffmpeg. Parse the RSS to get the video files, fetch them over the net if needed, then spit each one out to a command line like this:

ffmpeg -i episode1.mov -ab 128000 episode1.mp3

The -ab switch sets the output bit rate to 128 kbits/s on the audio file, adjust as needed.

Once you have the audio files you can reconstruct the RSS feed to link to the audio files if so desired.

Answer 5

http://www.zamzar.com/