Converting DVD Audio to CD Audio (Mac OS X)

May 17, 2004
Updated: December 2004

We bought a DVD Audio album mistakenly, instead of the CD Audio version. The problem was that we don't use the DVD player for anything other than watching rented movies and videos for the children. Although the DVD Audio content is recorded in 5.1/surround, we are not likely to start buying DVD Audio content in the near future.

I looked for a a freeware ripping/encoding program but the ones that I found for Windows would convert an entire disc if the full purchase price (about $30) was paid first. They look like they would be fine programs: the user interfaces are easy-to-use and they separated tracks individually. Furthermore, they can convert copy protected (CSS-encrypted) audio material. I didn't find an integrated program for the Mac.

So instead of buying a program to do that, I used free programs, or at least programs that I had, converting a DVD Audio disc into CD Audio. The DVD Audio album contained the same tracks and track lengths as the CD Audio album available for sale, so making iTunes recognize the CD was also important.

Steps for Converting DVD Audio into CD Audio

The following steps give an outline of how to convert a DVD Audio file to CD Audio using free programs available around May 2004.

My setup is:

Convert DVD Audio to .VOB

On the Mac I have used DVD Backup to rip the DVD files (removing CSS and region encoding) which I can later burn to a new DVD-R using Toast. This step usually produces .VOB, .IFO, and .BUP files. This step seems reasonably fast, I think faster than 1x DVD on a G4 1GHz machine with a SuperDrive.

Demux .VOB to .AC3

Next I used bbDEMUX to split the multiplexed .VOB files into its audio and video component streams, which might include .m2v or .ac3. Then I used mAC3DEC to convert the .ac3 file into AIFF (uncompressed Mac audio, or what you would get if you ripped a CD audio disc). This step takes something like a "48 kHz 5.1 AC-3" audio stream and converts it into "44.1 kHz Stereo AIFF". DVDs use a 48 kHz audio sample, with six channels, and CDs use 44.1 kHz audio sampling in two (stereo) channels.

Convert .AC3 to .AIFF

At this point you have a single .AIFF (or .MP3) file. In my case, the album was converted into a single file and not multiple tracks the way you would usually find it on a CD. Also, there were two .AIFF files, splitting the entire album into two contiguous audio streams. I concatenated the two .AIFF files into one and then saved a new .AIFF file that contained a single track of the entire album.

Split a Single Album AIFF into Track AIFFs

Next, I split the album into tracks that were the same length as the original CD album. Using the web-based search page, I found the album and the track lengths. Next, I selected AIFF tracks using QuickTime Pro and then exported it back to AIFF as one file. For each track I copied exactly the number of seconds that were listed on the FreeDB page, pasted it into a new QuickTime Pro window and exported each window's contents individually as AIFF.

Assemble AIFFs for Burning to CD

Now with a collection of individual tracks in hand, I imported (dragged) the files into iTunes. iTunes and programs that use the CDDB/FreeDB CD databases recognize CDs by track lengths, so there are a few ways to make a CD look very close to the original:
  1. Burn AIFF to CD directly with no pause between tracks. If you leave a slight pause (e.g. 2 seconds), then the disc will be burned with tracks that are two seconds longer, not with two seconds between tracks. The drawback is that the inter-track pause might not be long enough.
  2. Convert AIFF to MP3 and then burn the MP3 tracks. This seems to preserve the track lengths, but then you might have short gaps on your CD. Also, it has the obvious drawback that you are converting between a lossless format (AIFF) to lossy (MP3) and then back to the lossless (CD audio) format.
  3. Use Toast to create an audio CD. Drag the AIFF tracks and manually set the inter-track pause time. I chose to use this method.
Because I wanted to see whether iTunes would pick up the track titles from the CD track times, I first attempted some trial burns using CD-RW. After a successful burn, I imported the tracks into iTunes, ripping the CD and encoding it into MP3.

Random Comments

I'm not completely familiar with the DVD Audio format. The DVD Audio disc that we bought simply appears to be a DVD Video disc with still images and an audio track. No doubt you could find out a lot more elsewhere.

The audio quality of the CD seems to be "good enough." I'm not going to claim this is audiophile quality or that this is the best way to convert between formats.

The audio volume on most tracks seemed to be low. You might check to see that the volume is appropriate before you rip the CDs.

The DVD Audio jewel case is yet another size! It is larger than a CD case, smaller than a DVD Video case, and is wider than both. What are these guys thinking?

No doubt this excercise took more time than it was worth to go out and buy the CD. But what fun is that?

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