A really quick study into why Beatmania IIDX should not be played on a plasma display
Dave Britten
Sure, everybody praises plasma displays for their exceptional color and small size, but there is one major drawback of such a display that makes a game such as Beatmania almost unplayable. Beatmania requires timing your button presses with accuracy of almost a single video frame. However, plasma displays can introduce a delay of as much as 1/10 sec.
What causes this delay?
It's a simple matter of the displays using vastly different electronics from a standard CRT. With a CRT, the picture is scanned by the video beam in real time as the analog signal comes across the wire. Any delay in a CRT will be attributed to the propogation delay of the circuits, and will likely be on the order of nanoseconds (highly negligible, in other words.)
A plasma display (as well as an LCD) displays its image quite differently. Typically, the picture is drawn via a transistor array so as to match the contents of the display's built in video buffer. Now, to display a raster scanned analog video stream (composite, SVideo, VGA, etc.) the data must first be decoded, since it can't simply be fed directly to the electron gun and yoke magnets. The display must take the image as it comes in frame by frame, translate it to a digital image, and then send it out to its own display hardware. This is what causes the insane delays.
Prove it.
For the evidence, I've prepared some still frames captured from gameplay of Beatmania IIDX 8th Style connected to a plasma screen. The song being played is Frozen Ray on 7 Key mode. The camera is a Panasonic digital MiniDV camera, with a shutter rate of 30 frames per second. Annotations follow each picture, along with the time code of the frame (minute:second:frame).
00:03:27
Player's fingers moving downward to hit the notes seen in columns 1 and 5
Score - 183
00:03:28
Buttons have been hit, as evident by the lit LEDs
Score - 183
00:03:29
Right hand moving away from button 5
Score - 183
00:04:00
Both buttons have been pressed and released, but still no response from the screen
Score - 183
00:04:01
Lanes 1 and 5 have finally lit up, and the combo count is increased by 2
Score - 183, changing to 185
00:04:02
Lanes still lit, keys pressed and released long ago
Score - 185
00:04:03
A total of 4 points have been awarded for the two notes, signifying two Just Great judgements
Score - 187
Summary timeline
So here's what the video tells us...
00:03:27
00:03:28 - Buttons pressed
00:03:29
00:04:00
00:04:01 - Screen responds, showing the notes were actually hit with perfect timing
00:04:02
00:04:03
Since the camera uses a shutter speed of 30 frames per second, the time elapsed from the frame containing button presses to the frame in which the screen responds is approximately 3/30 seconds, or .1 seconds. Now, I understand that this is not a high shutter rate camera designed for taking high speed video, but the fact that the delay was so plainly evident with such simple equipment is plenty convincing.
Summary
Tell your arcade to get a damned CRT HDTV!!! Not only will this probably be cheaper, but it will make the game SO much easier to play, since you can tell visiually when you have to hit the notes. In the long run, everybody will have much more fun with the game when they don't have to try to compensate for a display that is not at all suited for this use.
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