If you have an Adafruit Fruit Jam, you can run the demo on that board [1]. It can stream 640x480 video off an SD card at 60fps, as well as display a static image from flash.
Also possibly of interest to HN, the decoder[2] is written in a new low level language called symbolasm[3], which seeks to combine the advantages of assembly language (it's possible to reason about and optimize performance with few limits) with some of the affordances of C, especially named variables and struct fields.
[1]: https://github.com/raphlinus/vic-2350
[2]: https://github.com/raphlinus/vic-2350/blob/main/image.sy
1) IMO pointless to put an emphasis on extreme decompression speed but not show numbers against JPEG even
2) BCx essentially does the same codebooking/paletting but more efficiently by allowing you to interpolate between two palette entries for an even larger compression
1) it may seem pointless until you realize it may allow targeting platforms which can't decode JPEG real time under certain situation
Which would have been clear if numbers were provided for a JPEG implementation in the repo
Why though? I thought it was pretty clear that you're not gonna decode JPEG pixels in 6 instructions.
>pointless to put an emphasis on extreme decompression speed but not show numbers against JPEG even
this decodes at HDMI line speed, 6 opcodes per pixel
This seems like straining the definition of "compression". We have a delta-coding filter and then palettization? That's it?
Edit: I should say, I find it surprising (but cool) that it apparently works so well. I would have expected errors to accumulate since the decoder has to un-delta-code. I saw mention of Floyd-Steinberg dithering and presumably that's what it's for; seems hard to get it working across multiple colour axes simultaneously, but the complexity is all in the encoder, so.
Floyd-Steinberg dithering preserves 100% of the quantization error by shifting it onto neighboring pixels (unlike eg Atkinson dithering which only preserves 75%[0]), so the lack of drift I guess isn't too surprising really.
As for tracking error across multiple color axes, I would naively assume it's a 3-vector (maybe in a linearized perceptual color space, or maybe RGB) and the error term the encoder minimizes is just the vector magnitude?
Very cool. I think this is best understood as a coding exercise for the embedded CPU instead of a 'real' video format, but no less impressive IMO
Worth noting that something perf-optimized for RP2350 is almost certainly not going to be optimal on a modern desktop-class core (with deep pipelines and wide ILP/SIMD).
Absolutely. This is optimized for highly resource constrained devices, not modern machines. I can tweak the README if that's at all confusing.
This reminds me a bit of Amiga HAM. Similar horizontal fringing.
I guess you could also call Amiga's HAM graphics mode a compression method. Getting 12-bit (4096 colors) with just 6 input bits, with the original Amiga chipset, often called as "OCS".
Or later 262144 colors with 8 input bits, with the AGA chipset.
Fun. Vaguely reminiscent of the Amiga HAM video mode.
I'm impressed. The imbalance between encoding and decoding speeds seems a useful strategy when you are building special purpose hardware and software applications. It seems if you're making a central source of data that is able to tolerate a much slower write process versus a quick read process that this approach can be advantageous. Maybe using this core method in a problem space which maps to the radio/signal broadcast process of many receivers but a central source of truth. I can imagine if you had an information base that changed slowly or which was pre-processed in a batch fashion, that it could use this method. It doesn't even need for the central data to be decoded into a graphical image.
I think this radio model could map the problem space for a centralized system that maintained a list of items and their prices which needed to be broadcast to the retail outlets on a regular basis.
Or a common cache storage to make some complex data manipulation calculations centrally performed available to a large number of satellites who just need the end results but do not have the need to do local calculation.
There are no private messages on HN. This, and your comments in the last 3 months look (AI) generated, which is prohibited in the guidelines[0] but also loathed by the community. Can only speculate, though.
Dave is a brave chap, and posts his personal phone number in his profile. You might be able to contact him that way, but, personally, I wouldn't. I don't think it's really appropriate. I'd say that your comment is sufficient, and not inflammatory.
But I do agree, the comment smells "AIsh." It may not be, however, if this is his standard writing style. I have been accused of being a "bot," for stuff I wrote ten years ago. It's my observation, that people tend to accuse any lengthy comments of being LLM-generated.
I'm trying to learn why I have been downvoted. Please reply or send me a private message so I can learn.
> especially named variables and struct fields
Don’t you get this from most macro assemblers? I know I’ve seen some very old and crusty ASM that nevertheless does structured programming and even limited OOP through macro-ASM facilities.
(That being said, symbolasm looks 1000x more ergonomic and “also communicates developer intent”-laden than any macro ASM ever did; and also is probably something you could learn once, while a project’s macros are specific to said project.)
I don't believe macro assemblers do a flow-based analysis to verify that the register allocation for variables is consistent; from what I understand the most you get is just a scoped alias for the name of the register. Of course, I could be missing something. If you know of anything beyond the relevant work I cite, please let me know.
Cool projects! symbolasm looks awesome. Brings back memories of playing around with fasm on MenuetOS and trying to wrap my head around assembler.