Recently I’ve released na_eofdec, a tool for decoding exotic and/or obscure formats. That release included F16 format support, but recently I’ve REd another one (PC Animate Plus / 3D WorkShop animation) and there’s yet another one waiting in the queue (Reflections animation). What unites them all is that they all employ simple compression scheme and (beside F16) they all have a 3D modelling program associated with them. And I’ve REd these formats by investigating the file format, they’re that simple.
F16 posed itself as “FLI but 16-bit” and it looks like its creators have failed to build an ecosystem out of it. I have encountered merely two demo samples at discmaster and nothing else. From technical point of view it’s either uncompressed intra frames or the rather familiar FLI delta compression scheme with its number of skip/run opcodes per line, just with small variations.
PC Animate Plus is more interesting as it has 4-, 8- and 16-bit content compressed, at least two format versions and several compression schemes. Plus it has some additional chunks for complex operations and even metadata telling e.g. which Voc file to play along. Intra frames are RLE-compressed, inter frames usually employ FLI delta compression (with small changes of course) but there’s another mode consisting of offsets and chunks of data to update. Another interesting thing is that it does not replace old pixels but XORs them with new data instead (maybe it comes from an alternative universe where 80×86 had REP XORMOVSB instruction).
And there’s Reflections animation. While I haven’t written a decoder for it yet, I can describe it already. I’m aware of three samples with rather uncommon 320×256 resolution and big-endian format. First frame is uncompressed, the rest seems to be simply “skip N 32-bit words, update M 32-bit words”. Writing a decoder for it should not be that hard…
Individually the formats are nothing to write about but together they form a group of FLI clones that poses some interest. Now that I’m done with MVS it’s either extending QuickTime support in NihAV or REing obscure formats, hopefully it will give me more material for my writing.