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What do you mean by preconverted? You mean like LZ4 compressed versions of graphics in the SNES's graphics format? If this is the case, I unfortunately don't have any. I should have said "raw SNES graphics file" instead ;) I just want a binary file containing SNES tiles data (in bitplan f...

Wow! That's a pretty large improvement... :shock: So even if you were maxing out the bandwidth to vram, you should still have well over half the CPU power left. Yeah that was the idea, i really wanted something allowing me to use full bandwidth and still have enough CPU time to work with :) I alway...

New update, i was able to optimize my unpacking code while keeping the same compression level. I managed to obtain a decompression rate between 10.5 KB up to 14-15 KB / frame, i am happy with that final result :) I will probably keep only 2 compression schemes for the next SGDK : - aplib (good compr...

I finally completed my own packer based on LZ4 but optimized for the 68000 CPU (and so taking advantage of 16 bits move), the idea was to get something fast enough for "live" sprite data unpacking and also giving a good compression rate. Ok so to start speed (tested on Kega Fusion): It var...

It's just about providing low / high priority to the mode 7 plan right ? I wonder why they called it EXTBG, that confused me as well the first time i saw it.

Kannagi> I guess you use the HDMA to set the M7 matrix regs ? That is the primary purpose for the HDMA actually.

I'm using 10.6 fixed point (signed) variable in SGDK, it's really convenient as you can manipulate it directly through 16 bits registers and it provides a good compromize between float part accuracy and integer part [-512..511] Of course that is not always enough but for me it's definitely a good ch...

Yeah of course it won't compress as much but i believe it could be not that bad and the speed improvement can be really high
The idea is about using it to (un)pack 4bpp GFX data anyway so i guess i won't make make a big different in compression ratio.
At least i hope so :p

Just tested LZ4, well, definitely better than LZO... I can unpack at ~5 KB / frame using an optimized version of the unpacker. I wonder if i can improve it but definitely look like a better solution than LZO after all. Edit: Can't get more than 5.5 KB / frame bringing others minors optimizations. Wh...

I'm curious about this LZO1X format but can't find a description of it anywhere... I only found the documentation on how to use the libraries and the source code of the decompressors. Do you have a link to a plain description of the format so I can see what the big deal is about this one? Unfortuna...

Tried to optimize my LZO1X unpacking code for 68k, can't obtain better than 3.5 KB / frame for an average compressed file...
I guess i will have to stick with UFTC for live real time sprite unpacking or get a look into LZ4 again.

Yeah that's all the problem. And even using byte stream compression on a 68000 is not really efficient when you always have small amount of byte to copy (between 1 to 4). Typically LZx compression should perform really well on 65816 CPU as it don't mind to have unaligned word operation while it does...

Yes but on an old machine you cannot have fast decompressing with modern compression scheme imo. If it was possible, i think it already exists . New compression algos are arriving every days, lz4 or snappy are modern and still provide fast unpacking =) Of course we couldn't use the best packer whic...

I think there is no magic solution, it depend what you need, speed or ratio ,but speed and ratio at same time is a chimera .. Now, there are some very good compressor ,better by far than those in 80/90's,to find a good compromise or well suited for a particular project. That is the idea, today we h...

Thanks Touko :) I actually experimented LZ4 just before switching to LZO but i could not find a proper minimal LZ4 packer source code working correctly and i definitely don't want to have a 10+ complexes sources files project for a simple compression algorithm, i just need a pack(..) / unpack(..) me...

I'm just doing some researchs now to try to find a good compression algorithm which can offer good compression ratio and very fast unpacking (by very fast I mean ~10KB of data per frame so you can use it to unpack sprite data for instance). I implemented Sik's UFTC compression in SGDK and it provide...