extracting audio out of an mp4 movie

This is the next step from the previous exercise, where we converted a dvd into ipod movie format, chapters and all. Great for the other part of we that has a video ipod. Those of us with “only” a nano that doesn’t play video need an audio-only file. So the next step is to get the audio part out of that. (Handbrake unfortunately doesn’t offer an audio only option, at least not that I can tell.)

So we could go back to the dvd probably, but for now I wanted to try to get the audio out of our freshly baked mp4 file. It’s not too difficult after all, and many tools exist out there. A quick test with ffmpegX worked fine, pulling out the audio into several formats (mp4, aac, ac3), taking only minutes each time. (I fumbled with the different formats looking for one that included chapter marking.)

Problem is, those didn’t seem to bring in the chapter marking. Picky picky picky. But chapters would make listening to individual lessons on the dvd much, much easier: there are parts that really are not necessary to hear repeatedly, so skipping around to specific chapters would be nice.

So we got audio. One big hour and a half chunk of it. Next challenge will be to pull out just the audio but this time with chapters. It might be necessary to go back to the dvd for that one… stay tuned. So to speak.

playing dvd movies on video ipod

The short story: Handbrake rocks, just get it (mac, windows, linux or source).

The long story…

We bought a great dvd to learn some more about open tuning guitar at Stefan Grossman’s guitarvideos.com. Thing is, after watching a couple times, we might want to practice without having to get out the dvd and turn on the computer. Not to mention that it’s not the most comfy place to play guitar, sitting in front of the computer.

Among the lucky ones, we have an ipod that plays video. Logical, right, we should be able to play the dvd on the ipod? That would be so much more convenient to listen to or watch than using the computer to play the dvd. Wouldn’t even need to have the visual, really, even just the audio would do.

Well, first things first. The dvd needs to be converted to the proper format for the ipod, mp4 video (the gory details of formats are beyond me). A little googling later, and I downloaded a free, open source application called Handbrake.

It doesn’t get any easier than this. Absolutely user friendly, worked-the-first-time-around satisfaction. Yes! With one page of instructions and screenshots you’re on your way. Handbrake spares you the details of formats and bit rates and all that with many preconfigured output format options, tucked away in a nice drawer of presets. All we had to do was point Handbrake to the dvd in the drive, pick the ipod video preset, go for a nice jog in the woods, and bingo! When we got home we had a freshly converted video ready for play on the ipod (it took about an hour on a Macbook Pro 2.33 GHz Core 2 Duo).

Initially we thought we’d aim for audio only, but after seeing the video we thought, mmmm ok, we’ll keep that! It looks fine, quality is quite good for our needs, and there happens to be enough space on the ipod for the video. Today anyway. (File size was about 500 MB for an hour and a half of video.)

The chapter structure was preserved, so skipping through on the ipod works great. Happy happy happy.

Just for the heck of it, I’ve continued the experiment and am trying to pull out the audio so I can play that on my don’t-need-no-stinking-video nano ipod. But that’s a different story, maybe later…

So why is it called Handbrake anyway? Something about parking on a hill? Switching gears on a slope?

video to flv or swf converters

These will be tested, just a virtual post-it note for now…
[update: notes added after testing]

Test object: convert 1.79 Megabyte QT .mov file, 40 sec, 320×240, no sound

Results:

Vertical Moon’s Video2swf
easy to use interface
converts to swf with player included
quality seems comparible to original
mac and windows
45 $US

Riva FLV Encoder
simple enough interface
relatively quick conversion
converts to flv (not swf), so have to integrate with flash player manually
quality seems good
windows only
free download

Both tools seem to do the job needed. Given that Video2swf will output both to swf and to flv formats, and is available for both Mac and Windows, the extra cost might be worth it. At 45 $US it’s not all that expensive. If you just need to make flv files from your videos and you’re on Windows, the free Riva FLV Encoder will do the trick.