How to Extract Audio from a DVD or Video File in Mac OS X

For whatever reason, one of the most difficult tasks to accomplish on Mac OS X is extracting ONLY the audio from a video or DVD. Above all, this is because there are a limited number of software tools to help you do this. Want to rip a DVD and convert it to a format compatible with your Mac, iPhone, or iPad? No problem. But just getting the audio (or even a part of it)? That’s a real pain. While you can pay for commercial software, getting the audio from a DVD for free requires a bit more time and effort. Here’s how you can extract the audio from virtually any video file, including DVDs.

Note: There are many ways to get from DVD/video file to audio file on Mac OS X. This article covers one way to do it, using only free software. If you think there’s a better/easier way to do it, post it in the comments section.

Squared 5 makes an excellent (and free) audio and video conversion tool called MPEG Streamclip. It has a feature called “Export Audio” that lets you save just the audio portion of a video file.

To export the entire audio track of a video file (not a DVD), follow these steps:

Drag the video file from the Finder onto the MPEG Streamclip window. Alternatively, you can open the file from the File menu.Select Export Audio from the File menu.A settings window will appear, which allows you to choose the audio format, sample rate, bit rate, and number of channels. The screenshot below gives you optimum settings if you want to turn the audio file into an AAC file compatible with QuickTime and iTunes. (Note that the stereo channels, auto sample rate, and 256 kbps bit rate are all default settings; you only need to change the format from “AIFF” to “MP4 AAC.”)
Press OK, and MPEG Streamclip will ask you to name the file and place it somewhere on your computer. The program will then go to work exporting the audio, which could take some time, depending on your computer’s speed and the format of the video file. Once finished, you are ready to listen to your file!

If you want to export only part of a video’s audio track, you can do this in MPEG Streamclip. Perform these steps:

On the video timeline near the bottom of the screen, move the crosshairs to the moment in the video file that you want to be the beginning of the audio file.Next, hold down the Shift key and drag the crosshairs to the point in the video file that you want to be the end of the audio track. Then let go of the Shift key.
Notice that the area on the timeline between your beginning and end points has turned a darker grey. The “In” and “Out” times list where in the video file (in minutes and seconds) the selected area begins and ends. From the Edit menu, select Trim to trim the portion of the video file MPEG Streamclip will look at to the area you selected.Once you have trimmed the video file, you can go back up to the previous instructions to export the audio.

The above instructions allow you to extract audio from a video file. A DVD is a different beast, and it presents two problems that you must solve before you can get the audio:

First, commercial DVDs are encrypted. You can’t just copy the files from a DVD’s VIDEO_TS folder and expect to be able to use them. This means you need to decrypt the files before you can get to the audio. MPEG Streamclip can’t do that.Second, DVD video files are in a format called VOB. VOB files use MPEG2 video/audio streams, which MPEG Streamclip can decode, but only if you have previously purchased (and have installed) Apple’s MPEG2 decoder. Further, one VOB file does not equal one movie or one TV show on a DVD. Often, a movie spans three or more VOB files, so you’d have to find a way to combine the files to get all of the audio from the movie.

How can you solve this problem? Well, unless you’re using commercial software, the sad reality is that you’re probably going to have to convert the DVD movie to an MP4 movie using Handbrake. I write “have to” because Handbrake will not let you only convert audio; you have to convert the video, too, and that can take multiple hours.

If you don’t have experience using Handbrake to rip DVDs, you can read my tutorial on using Handbrake to convert your DVDs. This will tell you everything you need to know to convert the DVD to a video file. Once you have a video file from your DVD, THEN you can start at the beginning of this tutorial, using your newly created video file in MPEG Streamclip

One Note: If you want to preserve the original version of the audio when ripping the DVD, you need to make one change to the instructions in the Handbrake tutorial. In the “Audio & Subtitles” subsection of the “Getting Dangerous” section, I wrote that you should choose AAC under the Audio Codec section of the Audio tab in Handbrake. That makes sense when you want the video file to play on an iPhone or iPad. But that instruction converts the audio from the DVD to an AAC format. You’re already going to do that in MPEG Streamclip, and the sound quality will degrade further if you have to do it twice. Instead, select “PCM” or “AC3 Passthru.” This will ensure the original audio goes in the video file.

That’s it! Did this tutorial work for you? Have a better idea on how to get the audio out of your video files? Write your thoughts in the comments section.

Tagged as: apple, audio, DVD, mac, Video