Update: Toshiba HD-A20 HD DVD Player, Firmware Version 2.5

Toshiba recently issued an update for its second-generation HD DVD players, primarily for the HD-A20 and the HD-XA2. I installed the update on an HD-A20, the middle model in Toshiba's HD DVD lineup (though shortly to be superceded in the launch of a third generation).

The update, version 2.5, is said to provide "support for 1080p/24 output, additional OSD languages, improved network connectivity supporting the download of web-enabled network content associated with certain HD DVD discs, and also addresses certain disc playback and HDMI/DVI related issues identified by Toshiba."

Installing the update was straightforward. As with all Toshiba updates, the output from an Internet connection (in my case a cable modem) is fed directly into the player via the latter's Ethernet port. You will need a connection to a video display to see the menus. You then simply follow the instruction in your owner's manual and on-screen. No computer is required, though presumably if you have Internet access you have one! If you don't have Internet access or a computer, however, Toshiba will send you, on request, a disc that will load the update directly into the player.

Before the Update
To better judge where you are, you have to know where you've been. Even before the update, the Toshiba A20 was an excellent HD DVD player, but it did have some limitations. First among these is that like all of the company's first and second-generation HD DVD machines, it could not output 1080p/24 out of the box. And it will soon be replaced by a third generation player, the HD-A30.

The HD-A20 is also somewhat compromised by how it arrives at its 1080p/60 output. It was rumored to produce its 1080p/60 output by first converting 1080p/24 to 1080i/30. (While not all HD DVDs are mastered at 1080p/24, as we shall see, nearly all of them—and all movie titles—are.)

It's likely that such a seemingly odd design choice simplifies engineering and cuts costs. If done well, it could be transparent, but that will depend on how the player's video processing converts 1080p/24 to 1080i/30, and then 1080i/30 to 1080p/60. The first step is relatively straightforward—add 3/2 pulldown, then split each frame into two fields. The second step, deinterlacing, is much more complicated.

(Note: In some sources you will see 1080i/30 referred to as 1080i/60. The 30 in 1080i/30 refers to the number of frames per second. The 60 in 1080i/60 refers to the number of fields per second. Since there are two fields per interlaced frame, both designations are describing the same thing. I prefer the designation 1080i/30, since that is consistent with 1080p/60 and 1080p/24—that is, the number after the slash always refers to frames per second, not fields. Some manufacturers use 1080i/60, or sometimes 1080/60i, in their specs, probably because it's a bigger, more impressive number.)

I was able to confirm that the HD-A20 does, in fact, first convert a 1080p/24 film source to 1080i, and then deinterlace that 1080i to 1080p/60 prior to output. Test patterns viewed at 1080i/30 were mostly pristine, but a 1080p/60 output showed clear signs of rudimentary deinterlacing.

Specifically, the 1080i-to-1080p step uses bobbing. Bobbing is a relatively primitive deinterlacing technique that takes the two fields of each interlaced image and interpolates extra lines for each field, and then displaying them sequentially rather than weaving them back together. The more sophisticated approach is motive adaptive deinterlacing, in which the processor weaves the two fields together when there's little motion and bobs them together when there's fast motion.

But this isn't the place for an extensive review of deinterlacing techniques. The point here is that there would not be any evidence of deinterlacing at all if the player simply converted a 1080p/24 directly to 1080p/60.

The player also added subtle and non-defeatable edge enhancement to its 1080p/60 output. This was not present with a 1080i/30 output, again suggesting internal deinterlacing was being performed when there should be none.

What About the Update?
So far, we've been dealing with the HD-A20 pre-update. What did the update change?

I'll restrict my comments here to the basic performance, not including network connectivity and "certain disc playback and HDMI/DVI related issues."

Let me note immediately that I experienced no lip sync problems with the updated HD-A20. Lip sync and timing errors relating to the update have been reported online, but mainly with respect to the HD-XA2.

Back on the video side, most of the player's post-update test results for its 1080i/30 and 1080p/60 output options were the same as pre-update. That is, the update did not improve the 1080i-to-1080p deinterlacing (it remained essentially the same), nor did it eliminate the edge enhancement added in the player's deinterlacing process.

And 1080p/24?
The short answer here is that yes, the update does add 1080p/24 which, for the most part, is useful and effective.

There was additional good news here as well. When I set the player's output to 1080p/24 with a film-based HD DVD there was no evidence of bobbing or edge enhancement. The latter two problems apparently exist only with a 1080p/60 output. When you set the player to 1080p/24, the 1080p/24 source on the disc remains progressive all the way to the player's output.

New readers need to be aware, of course, that a 1080p/24 output is only useful if your display will accept it and display it properly. That means it must maintain the 24 frames per second rate. In most cases displays that do this will upconvert the 24fps rate to a multiple of 24fps, or at least 48fps. There are still a few displays on the market that will not accept 1080p/24, and others that will, but merely convert it to 1080p/60 prior to displaying it- a solution that doesn't provide the smooth motion of displaying at a direct multiple of 24fps. However, you might still see a benefit as using the 1080p/24 output would avoid the 1080i conversion, and the poor deinterlacing of 1080i-1080p in the A20.