Return to EQ index
All information in these pages is copyright (c) 1989-2003 by Roger Nichols. All rights reserved. Permission for personal reference only, and may not be reproduced by any method without written permission.
DVD-DTS-CD-RW-PDQ
By Roger Nichols
Re-purposing the Mix
I have been mixing some 5.1 versions of albums that I had previously mixed in stereo. The original mixes were done completely in Pro Tools. I opened up a copy of the stereo session document, and changed the output assignment to the 5.1 output instead of the stereo output. From there it was a simple task to change the position of some of the instruments and spiff up the reverbs.
The mixes were finished and bounced to disc as 5.1 split audio .wav files. The producer wanted copies so that he could listen on his home surround system. The problem was that he did not have a DVD-A audio player, he only had a Toshiba DVD player that was three or four years old. “No problem, I’ll make a disc you can play, and I will get it to you tomorrow.” Famous last words.
DTS-CD… Almost
I knew from experience that the Toshiba player hates DVD-R discs, so making a DVD with AC-3 or DTS surround was out of the question. My best bet was to make a 44.1kHz DTS-CD. If it would not play in the Toshiba, then he could play it in his CD player, which was also connected, digitally to his receiver.
My surround mixes were done on a Mac. I needed to move them over the network to the PC that ran SurCode DVD-DTS. This is where the split 5.1 (6 mono files) gets encoded into a DTS stream for the CD. Encoding went fine, and the output .wav files were moved back over to the Mac.
I use Toast with Jam to burn all of my CDs. Toast in Disc-At-Once mode would work fine for this little job. I imported the files into Toast, which immediately changed them into .aif files. That is all right because the audio data stays the same and only the header information changes. I set all of the spacing between cuts to ZERO and burned the CD.
After the burn, I placed the CD into my DVD player and pressed play. When you play a DTS-CD, the player expects the audio stream to be PCM digital audio so there is no muting. When the initial burst of the DTS stream hits the receiver (in my case, the Lexicon MC-1 preamp) some of the stream gets through before the DTS decoder kicks in. This results in a rather loud digital tearing sound for about 1/4 of a second. Everyone is warned, and the volume is lowered for this unwelcome transient. Volume back to normal, the music starts, and all is perfect. That is, until you come to the splice between the songs. Since each song is from a different mix and encoded separately, there is a glitch in the DTS packet data at the transition between the two songs. There could be anything from a small click to another digital noise burst because of the transition.
Plan-B
Well, there was only one way to avoid the digital glitches. The whole album had to be encoded as one long file so that there would be no glitches between cuts. I started a new session in Pro Tools and imported all eight songs. Each song was contained in a 6 channel audio track. I placed all of the songs in the correct order and adjusted the space between them to be exactly what I wanted. I then bounced the entire album to disc at one time. After the bounce was complete, I copied the 6 files over to the PC for encoding. The files were successfully encoded into one long DTS stream as a .wav file.
Wait. I can’t import the file into Toast for the burn because I need to have start IDs for each song. Toast would only burn one long 45 minute long song. I needed to be able to find and play a single song if I (or the client) wanted to. But Jam will do it; you just have to cheat a little bit because you cannot listen to the DTS stream to figure out where to make the edits. The way around this is to go back and open the session I used to connect all of the 5.1 mixes together. If you highlight each song region, and the timeline is set to Hours:Minutes:Seconds, you can write down the start and stop time of each song.
Now, open Jam. Remember the long DTS encoded file? In this case the album had nine songs, so I drag the same long DTS encoded file into Jam nine times. At first glance it looks like the CD will be 540 minutes long, but that will soon be fixed. In Jam, if you click on the song length, you are given the option to change the start and end times of the track within the file, just like making region markers in an external editing program. The first song will be set to start at 00:00:00 and end at 2:27:28. The next song will start at 2:27:28 into the file and end at 5:32:98 (the frame size is set to 100 frames per second) and so on down the line. Each song comes from the same file, but at different positions. It is very important to set the space between cuts to ZERO, except for the space before the first song, which is 2 seconds. Also re-check that the end time of each song is exactly the same as the start time of the next song.
This is exactly like flying on instruments. You have to trust (until you hear playback later) that the numbers will line up correctly. You can’t play back the DTS stream to check your entries.
The next step is to burn a disk and see how it plays back in the DVD player. In this case everything turned out perfect. There was the noise at the start of the disc, but the transitions between cuts were perfect. Because the DTS stream was continuous, there were no clicks or noises. If you skip around from cut to cut you will hear a noise as the DTS decoder syncs up, but if you play through the entire album there will be nothing but the program material you intended to be there, nothing more.
Finally
Some older DVD players like the Toshiba do not like CD-R, but it turns out that CD-RW has about the same reflectivity as a DVD. In most cases the Toshiba and other troubled players will do just fine with a CD-RW. In my client’s player, the CD-RW worked perfectly. He never even knew that it took three days to figure this all out. Oops! I guess he will after he reads this!