Re: Apple II Music Video - Welcome to the Jungle!!

["Frank M." <frank_o_rama@hotmail.com>]

BLuRry wrote:
> Frank M. wrote:
> > Continuing my previous experiments with rasterizing video on an //e,
> > I've finished rendering all 6,462 frames for the music video to Guns N
> > Roses "Welcome to the Jungle". Each frame is a single lo-res GR screen
> > dump. Obviously this only will work on a machine with a CompactFlash
> > drive or in an emulator.
>
> Very cool -- and something I never would have expected out of a //e.
> But here's some suggestions that can speed it up.
>
> 1) Don't use + in the print statements, use the ; operator
> 2) Don't convert the loop variable to a string or use an if statement
> to zero-pad it.  Just split that part off to a couple of extra loops
> 3) Break each directory into a separate loop and change the prefix
> in-between the loops.  You're causing a lot of extra conditional logic
> to be processed.  If you never noticed, applesoft basic is slow. ;-)
>
> If you follow these three recommendations, you'll see it run really
> fast for the first few frames and then slow down after about 50 or so
> frames.  Ultimately, you'll need to break up the directory structure a
> lot more -- or figure out some other way to reduce the number of
> entries in the directory (is it slower to read from a non-zero location
> starting point of a file?  if so, how much slower?)  Another
> possibility is to pre-cache frames into a ram card and use the mem copy
> to move over pages as needed during the VBL.  Using this you could load
> chunks of frames at a go (probably a lot faster) and avoid having to
> hit the filesystem as much.
>
> Apart from that, because you're using a very palette-reduced rendition
> of a live motion video it gets very grainy because it's downright
> impossible to find good approximate color matches.  If you convert
> something that uses a simpler color palette and line art like a cartoon
> it will be easier to make things out.  If you wanted a real statement
> of irony, I'd recommend "futurama" -- especially the episode where they
> reveal Bender's brain is a 6502.  ;-)  But that's just my personal
> taste.


Here's my next course of actions.....

breaking files into smaller subdirectories
fix conditionals and prefix info
drop leading zeros from frame filenames to lose all the IF statements

if you want to get really crazy you could.....

have the program pre-load track/sector info for each frame so frame
loads don't require a trip to the directory (then you could keep every
frame in a single directory). and also code everything in ML. yeah,
like that's gonna happen. it would be interesting to know what
theoretical speed it could run at give a stock 1.0mhz proc and a
standard CFFA/CF setup.

I think the colors work because there's so much dithering of single
frames, in addition to the flickering between frames, that it tends to
smooth out in your eye. strangely, squinting harder makes the video
seem more clear. it's like your brain fills in the missing parts. and
fast frame rates really help.

I always identified with bender. kinda kludgey and cantankerous yet
hardworking sort of. you can always get it to do what you want, but
it's a matter of how much effort it is.

-f-