Playing the Playing Field

In Uncategorizedby tfwm

As you may know (or you’ll soon find out), DVD Recordables will not play in 100% of the installed base of set top players or computer DVD Rom drives with software players. There are several key reasons for this; here are two biggies:

The DVD book specification for DVD Recordable wasn’t finalized until after millions of DVD players had already shipped. So lots of DVD players out there don’t know what a DVD Recordable is. And then, the adoption of DVD-R by player manufacturers afterwards was slower than one would have hoped. Luckily there are ways to fool these older players into playing DVD recordables; basically inducing them to believe a replicated DVD-Rom has been inserted. I’ll go over how to do that in this article.

Low DVD recordable compatibility comes from a lack of understanding by us authors; of the difference between replicated DVD-Roms and DVD Recordables. These are two completely different types of discs. So, let’s go over the main considerations of how to prepare video and audio for DVD recordables.

Of course, the best thing we can do, for all concerned, is get the DVD project to a replicator. Glass mastered discs manufactured at a replication plant are almost 100% compatible. If you have no other choice than to distribute your show on one of the DVD Recordable formats, then here are a few considerations.

First, a brief mention some basics to achieve the highest compatibility for DVD Recordables:

Distribute your final show on DVD+R or DVD-R.

The DVD re-writable formats DVD+RW and DVD-RW will be less compatible with players out there no matter what we do.

Use name brand media.

We shouldn’t risk our final distribution show to unknown quality discs. I like Maxell, Verbatum, and Memorex, but there are other name brands that will work well.

Make sure your DVD writer has the latest firmware installed.

Lots of changes are going on as manufacturers fine-tune their products. One good firmware update can make a difference in playability of the discs written with the device (you should have seen the early days!)

Write DVD-R at only 1X speeds

Pioneer’s DVD-R format does best written slowly. This is a secret DVD professionals have long known. Philips DVD+R format can safely be written at the higher speeds.

Here’s how we can deal with those older players out there.

Consider adopting the DVD+R/+RW format.

Philips and HP came out with a much-anticipated new DVD Recordable format called DVD+RW a little over a year ago. This format has major improvements over the older DVD Forum approved Pioneer DVD-R format (Pioneer threw in the towel recently with their announcement that the new A06 writer will support the DVD+RW format, as well as their DVD-R), and was designed to be compatible with the installed base of players out there. I won’t go into all the technical improvements here; you can find them listed at this website:

There is an ability for the DVD+RW format (which includes the write-once DVD+R) to set the recorder to write what’s called the “compatibility bit setting” (doesn’t work for all brands of DVD+RW or Multi-format writers like the upcoming Pioneer A06 or Sony 500U).

The HP 200i and 300i ship with a utility to set the drive up to write a “DVD-Rom” designation in the lead-in area of the disc. For these drives, you choose to write in “mode 2”. Then, for all the DVD+R’s you write with, players out there will see the drive as replicated discs. And it works!

Here’s a link to more info on this nifty feature:

Asset preparation for DVD-Recordables
The most important consideration for increasing the chances that our DVD Recordables will play in the highest percentage of players out there is to make sure the combined data rate of the Mpeg 2 video and audio streams on the disc are as low as possible.

If you’re distributing your production far and wide, then I recommend that you don’t go over 6mbps for the Mpeg 2 video assets, and that you compress your PCM audio to AC3, or better known as Dolby Digital; keeping the combined data rate as close to 6mbps as possible.

Even though DVD Recordables have the same reflectivity as dual layer replicated DVDs, they don’t have the wider data pits that make DVD-9s (single-sided dual data layer replicated discs) easily readable by DVD players. The wider data pits of DVD-9 limit each layer to only 4.26 Gigs of data; make it easier for the player to read. DVD+R and -R have the same smaller sized data pits as the more reflective DVD-5 (single sided, single layer replicated disc), which allow the same size single layer platter to hold 4.7 Gigs of data. So the only way DVD Recordables can compensate for having the same less reflectivity rating as a DVD-9, but the same data pit size as the more reflective DVD-5, is to lower the data rate to make it easier on the player to read.

Lowering the data rate means we have to have a good quality Mpeg 2 encoder. I recommend ProCoder (yes, even though I’m big on DVD Studio Pro, I set my clients up with a dual something or other Windows box running ProCoder to get their Mpeg 2 elementary streams!) and Cinema Craft Basic, and TMPG Encoder (MainConcept’s encoder is coming along nicely as well). Apple is so mad at me for recommending Windows encoders (I caused a stampede to ProCoder in the Mac community), that their new Compressor encoder due out by the time you read this, has been dubbed a “ProCoder Killer” by the development team I’ve been told (we’ll see :-). But you get the idea. Lower data rates with marginal encoders would sacrifice the quality of our show, which we don’t want to do.

Mpeg 2 settings in the encoder
Almost as important as the lower bit rates for DVD Recordable distribution are the settings in the Mpeg 2 encoder. Here’s part of the ProCoder Advanced Mpeg 2 settings Window.

Notice half way down in the settings window there’s a check mark next to the “Use Closed GOP” setting. This is very important. Without going into the technical details; Closed GOP (part of Mpeg 2’s “Group of Pictures” encoding scheme) streams are MUCH easier for DVD players to read than Open GOP Mpeg 2 streams. A 6mbps Open GOP stream is the equivalent of approximately a much higher data rate of an 8mbps Closed GOP stream, or so; insofar as playability is concerned in players. Basically the way it works is, Open GOP streams are allowed to look outside their GOPs to help reconstruct the picture upon decoding, which does increase quality at any given bit rate. Closed GOP streams, on the other hand, are confined to their designated frames, which is much easier to decode for players. Open GOP streams are OK to use on replicated discs, but can cause some players to stutter on an otherwise very playable DVD-Recordable.

The above settings in ProCoder will give most any show excellent quality. Notice I kept the top end of the Mpeg stream to 6mbps, with the average set to 4.7mbps. That will keep the varying bit rate, depending on the scene complexity of the show, within the safe range for DVD Recordables.

There’s more to it of course. But I hope I’ve given you some things to think about. Oh, it’s also a good idea to prepare a release for your clients to sign, showing you’ve briefed them on the current state of DVD Recordable compatibility, and that you are absolved of all responsibility in case they run into a player that won’t play the disc. Here’s your chance to ask them one last time if they’re sure they don’t want to go to replication with the project!