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ColecoVision Slideshow Sample in diverse compressed formats

lossless compression pletter dan1 dan3 slideshow sample coleco z80

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#1 newcoleco OFFLINE  

newcoleco

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Posted Fri Jan 26, 2018 10:28 PM

DOWNLOAD

 

ColecoVision SlideShow Sample in 5 formats: Attached File  SLIDESHOW SAMPLE.ZIP   131.8KB   58 downloads

 

 

README.TXT

 

Hello everyone,

 

My name is NewColeco and I'm gonna tell you what I've been worked on during the last 3 years.

 

Not everyone is aware that graphics are very difficult to add in our beloved homebrew games, especially within the standard 32K cartridge size. To make things worse, some graphics cannot be compressed at all to keep the action fluid and fast.

 

In order to add great looking bitmap screens and tilesets into our projects, we use data compression.

 

I've been working very hard on lossless data compression for our graphics data. My new compressed formats are named DAN1, DAN2, and DAN3; they work especially well for big graphics like charset and bitmap screens. They are, technically speaking, LZ77 variants and developed based on our graphics need.

 

The ZIP file in the download section contains 5 files of the exact same slideshow sample, the only difference is the data compression format used in each one of them.

 

Information about the Slideshow ROM files:

  • in Pletter - ROM size 27730 bytes.
  • in ZX7 - ROM size 27665 bytes.
  • in DAN1 - ROM size 27094 bytes.
  • in DAN1 without RLE support - ROM size 27078 bytes.
  • in DAN3 - ROM size 26999 bytes.

For this slideshow sample, saving about 700 bytes is a big deal; should be enough to add an extra picture without going over 32K.

 

Now you know what I've been working on lately.

 

Question?

 

Thanks for reading!



#2 youki OFFLINE  

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Posted Sat Jan 27, 2018 3:12 PM

i did not manage to run the rom on BlueMSX emulator. :(

 

Did somebody try the Rom?

 

Btw , in my games i use DAN0 format in general , from my experience it is alway lot of more efficient than Pletter. But it is surely specific how i build the image in my games.

 

I did not tried the new format yet. But seeing rom size difference , i'm pretty sure that Dan0 will be still more efficient in case of my games.



#3 Ikrananka OFFLINE  

Ikrananka

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Posted Sat Jan 27, 2018 3:18 PM

i did not manage to run the rom on BlueMSX emulator. :(

 

Did somebody try the Rom?

 

They worked in CoolCV for me.



#4 newcoleco OFFLINE  

newcoleco

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Posted Sat Jan 27, 2018 5:12 PM

i did not manage to run the rom on BlueMSX emulator. :(
 
Did somebody try the Rom?


These ROM files are working just fine on real hardware, aka standard ColecoVision game system, and they work on BlueMSX (vanilla ColecoVision settings) on my computer just fine as well.
 

Btw , in my games i use DAN0 format in general , from my experience it is alway lot of more efficient than Pletter. But it is surely specific how i build the image in my games.
 
I've not tried the new format yet. But seeing rom size difference , i'm pretty sure that Dan0 will be still more efficient in case of my games.


Depending on your data and your needs, one data compression method should work better than another. And it's not necessary to use "the best" option when you can use a method you like and still do the job.

Side note: DAN0 is not a LZ77 variant, it's a boosted RLE with fixed Huffman encoding and a little extra bytes saving if it reuse common bytes between data tables. Pletter is a LZ77 variant without any optimization like a Huffman encoding. DAN1, DAN2 and DAN3 are LZ77 variants more focussed on saving bits than Pletter and with a fixed-Huffman encoding optimization, and RLE optimization for DAN1 and DAN3.

They worked in CoolCV for me.


Glad to hear CoolCV can run them just fine.





Also tagged with one or more of these keywords: lossless, compression, pletter, dan1, dan3, slideshow, sample, coleco, z80

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