On PS3 and Blu-Ray
My good friend Ozymandias has been going off lately about the decision to put a Blu-Ray drive in the PlayStation3. Aside from the fact that he works for Microsoft, I really don't see how he could argue that the Blu-Ray drive is not exactly the right move for games on PS3, when it comes to capacity. Here are two reasons why.
The Historical Perspective
At the beginning of the lifecycle of PS2, most games shipped on CD-ROM. These discs fit up to about 700MB of data. At the current stage of PS2, there are a few games that have shipped on DVD-9 discs. These dual-layer DVDs can hold up to 8.5GB, but one can assume that they are holding at least 4.7GB of data (the size of a single-layer DVD), or the publisher would have chosen to ship them on DVD-5.
So across the lifespan of PS2 so far, games have spanned a range of nearly 700MB to just over 4.7GB, or somewhere around a 7x size increase.
For the sake of argument, let's say the *average* game lands around 2GB right now. This would seem to indicate that conservatively we'd want to use a media format for PS3 with a maximum capacity of at least 7 x 2GB, or 14GB. That won't fit on a dual layer DVD. The only logical choices are HD-DVD or Blu-Ray. A single layer Blu-Ray disc is 25GB. Seems like this a good choice from a historical standpoint.
The Content Perspective
Let's keep running with our 2GB average game size. Relatively little of that data is game code; most of it is vertex data, texture data, audio, and video.
The number of vertices that Xbox360 and PS3 can crunch compared to the previous generation is at least 4x. 4 x 2GB is 8GB, Which would put us at a DVD-9 size if all the data were vertices. (Of course, it isn't.)
The texture resolutions have increased closer to 16x, which would push us to 32GB if all that data was texture. Yikes!
Audio on PS2 was mostly stereo, two channels. PS3 is 5.1. That's a 3x size increase without even considering fidelity.
Default video format has moved from 480i, or roughly 640x480 at 30 frames per second (9.2 million pixels per second), to 720p. 720p is 1280x720 at 60 frames per second (55.3 million pixels per second). That's about a 6x size increase. 6 x 2GB would again push us over the DVD-9 size.
And remember we're just doing back-of-the-napkin calculations here of an average 2GB game. We have 4x, 16x, 3x, 6x multiplied by 2GB. Perhaps an average game could squeeze onto a DVD-9. But the fact that this is an average means that many games are much larger. How can they possibly fit onto the Xbox360's DVD-9 long-term?
Plus ideally, shouldn't game developers feel they have enough room on disc that it doesn't constrain them? We want them to create amazing experiences, not mediocre ones. Why wouldn't you go with a larger capacity format than DVD-9?
The Other Sides of the Coin: Throughput and Market Demand
Admittedly, Blu-Ray looks dicey from several non-capacity angles. Blu-Ray movies require a 1.5x Blu-Ray drive, or 54Mbits/second. Sony announced that PS3 uses a 2x BD drive, which is 72Mbits/second or 9MB/second. The Xbox360 uses a 12x DVD, which should give it about 16MB/second. That is significantly faster for games and will result in shorter load times. And that 12x DVD drive should be a whole lot cheaper. (Note that the PS3 drive will do 8x DVD, and even that is faster than 2x BD.)
Of course the big play from Sony is that Blu-Ray will not only be popular for games, it will also be popular for movies. One of the reasons the PS2 initially sold so well in Japan is that it was very inexpensive for a DVD player. But unfortunately we're just a bit early on Blu-Ray awareness at this point for something similar to likely happen with PS3.
According to Wikipedia, DVD players launched in Japan in 1996. They came to the US in 1997, and by the spring of 1999, DVD players had reached down to the $300 price point. PS2 launched in the US in 2000.
Contrasting that with Blu-Ray, BD players launched in Japan in 2003. They really didn't hit the US significantly until this year, 2006. BD players currently are around $1000 in the US. And the PS3 is launching this year, 2006. From one perspective PS3 is launching just one year earlier than the time from DVD launch to PS2 launch in Japan. But Blu-Ray drives and discs have been very sparse so marketplace awareness is slight - it is more accurate to compare against the BD launches of 2006, which would make Blu-Ray for PS3 significantly earlier in the marketplace than was DVD for PS2.
The result is that the Blu-Ray drives for PS3 are expensive, and the demand for Blu-Ray movies in the marketplace has not flowered open yet. PS3 could stoke that fire, but it doesn't seem likely that Blu-Ray will significantly drive sales of the PS3 beyond a small hardcore market, in the short term.
...
It seems the decision to include Blu-Ray on PS3 must have been a difficult one. Long term it seems like a smart move, at least from the perspective of capacity. But short term that decision has definitely had some striking ramifications for PS3.
It's an interesting play, and not one that can be quickly categorized as the "right" or "wrong" thing. :-)
Now don't get me started about the idea of shipping an HD-DVD drive for Xbox360!
