Cool Trick for FMV railshooters

[kool kitty89]

http://www.youtube.com/watch?v=FS20pG0cw5I


That example isn't strictly FMV, but I think i is streaming (looping) video, from a cartridge in that case.

What's done appears to be making the streaming BG screen bigger than the viewing area (whatever the window size is), then scrolling to further edges of the streaming BG image to give the illusion of an actual 3D environment.

On the Sega CD the problem would be that the viewing area is already limited in most cases, so either the framerate would drop and larger frames would be used, or the viewing area would shrink even more. Not so much of a limit on some other platforms though (like 3DO).
That would have been a cool effect to use in Novastorm, or Siplheed for that matter.

[tomaitheous]

IIRC, all the "streams" are actually 1/4 in size of the full frame. They use a combination of horizontal and vertical mirroring to show it as 4 parts or a whole screen. So that cuts down on the bandwidth and the storage size (being a cart).

[kool kitty89]

Cool, that would help explain how they managed to fit it on the cart: I'd assume it was compressed as well. (and the low resolution of the GBA screen)
That would also have been a cool effect to use on FMV games (using the term loosely), granted the use is limited to symmetrical environments.
Another feature of that game was using the streams for only portions of the screen in some cases, like the ocean in that one section. (with the main BG being scrolling 2D)

On a disc based console it would be tougher to loop the streaming animation seamlessly due to seek times (at least on consoles with limited caches/buffers -unless you buffered outside of the CD-ROM cache), though in that case you've got the big advantage of high mass storage capacity, so it's much less of a limitation.


I was impressed how significant such a relatively simple effect (panning) enhanced perception of the game: it really does give a feel of greater depth than a fixed screen video stream.
Even though the perspective doesn't actually change, the scrolling/panning really gives the illusion that it does.


Were there any earlier examples of such use of streaming animations and panning? (I've seen lots of FMV games, plenty of which were rail shooters, but none using that effect -or mirroring for that matter, or using streaming video animation for a relatively simple part of the BG, like the ocean)
Bram Stoker's Dracula on the Sega CD uses streaming video dynamically applied as a scrolling background, but that's not really the same thing.

[crazyteknohed]

What's done appears to be making the streaming BG screen bigger than the viewing area (whatever the window size is), then scrolling to further edges of the streaming BG image to give the illusion of an actual 3D environment.

Didn't Rebel Assualt use such a technique for the X-Wing sequences? I could be wrong though; I haven't played the game in the last fifteen years or so.

[kool kitty89]

Which X-Wing sequences?

I never got past the second Tatooine stage (I think that's what it was): whatever came after the attack on a Star Destroyer.

But no, I don't remember that: maybe on one of the A-Wing stages, but most seemed to either be moving a cursor or a 3rd person view over a fixed perspective streaming background.
I'll take a look at some videos...

Regardless, I don't remember anything impressing me like Iridion.

[kool kitty89]

It seems Rebel Assault does use panning in a number of areas for similar effects (including the overhead part with the Skyhopper training stage): at least in the PC version. Still it doesn't have the same feel of depth as the GBA game, maybe it's due to the corridor/tunnel type environment in that case. (the death star trench would be the best parallel, though the A-Wing canyon section is similar as well, some of the other X-Wing stages use it to good affect as well)


Edit: I found a video of the final stage:
http://www.youtube.com/watch?v=hPKq3Dod1Ks


That definitely uses that effect well, similar to the GBA, really giving an illusion of a 3D perspective.


Edit: Just watched a high quality video of the Sega CD (almost definitely an emulator) and wow it looks nasty.
It's not dithered like Sewer Shark or posterized like Nova Storm... No, no, there's color loss all right, but not just like a bitmap image being converted to low color format without dithering.. (and obviously far worse than Silpheed which almost seems like lossless compression -no visible artifacting and far too high a framerate and screen size for uncompressed video)

It's absolutely FULL of really nasty microblocking (I assume using that cinepak derivative -it looks like a super high compression JPEG), possibly the worst on the CD, and on top of that the framerate is really low (seems like under 8fps). And the video tears, but I think that's due to the capture software.

It's to the point where it would probably have been much better if they cut the resolution by 1/2 (vertically and horizontally) and used the ASIC to scale it to a larger screen size and use less compression. (it's so blocky already, halving the resolution -1/4 the screen area- would probably not be noticeable -while the higher framerate and reduced artifacting would help a lot)
Actually, the heavy dithering method of sewer shark obscures any actual microblocking from being discernable. (it also runs at 15 fps -I think Silpheed does too, but Novastorm is lower iirc)

Unlike other FMV games on the CD, Rebel Assault also has a streaming audio soundtrack in-game (as well as separate voice samples and sound effects), but that wouldn't account that much for the video quality. (sounds like 8 or 11 kHz, so wouldn't use too much of the CD bandwidth)
I assume the larger screen size (extra area for panning) contributed to the heavy artifacting: cutting the viewing area size would have been preferable too IMO. (even if it was sewer shark sized that looks much better -and/or dropping the resolution and scaling to maintain screen size)
Streaming sprite animations all seems to be handled separately (actual sprites), so any change in the compression to the BG wouldn't habe to affect those either. (as it is the sprites look much better than the BG -and open space battle sections look pretty good)

http://www.youtube.com/watch?v=F6yOX2vmxgY (note it's a longplay and over an hour long; the death star section starts at ~50:30)
Large surface areas look worst, like Mos Eisley (see below) and the Death Star section.

[Anonymouse]

I would love to see someone put a tech demo together of this to see if its possible on the Sega CD though i suspect it probably isnt. Low colour count like silpheed would look best

[TmEE]

doing what Iridion does requires massive amount of DMA, so much you have not much left for other stuff unless you're fine with half speed (25/30) FPS... in 50Hz you will be able to get full speed and have room for more stuff.

[Anonymouse]

Would love to see it in action. :-)

[mrbigreddog]

The 3DO version didn't look much better, but ran ALOT faster!

[kool kitty89]

That looks much better to me, though the deinterlacing of the video sucks. (color loss and dithering is obviously less, but the greatly reduced compression artifacting is obvious, and that's one of the more forgiving levels on the Sega CD, again the Death Star sections are the absolute worst)

I thought it was the PC version I posted before, but I can't seem to find the reference now. It does seem to look nicer than the 3DO. (though the video is lower quality -ther than lack of interlacing and audio distortion)
http://www.youtube.com/watch?v=IG3cIpm-9yA



This one's definitely the DOS version:
http://www.youtube.com/watch?v=TxHRWTPmvlo



Too bad it's nearly impossible to tell what artifacting is from the video recompression and what's from the original video. (same pretty much true for all except the Sega CD, which is so blatant it's not funny)