jpap

7 ms·

1.
by jpap 1y ago
Agreed; I do this all the time as well. I don't think it as "guessing" per se, I think of it as forming a hypothesis based on the intersection of my existing knowledge of the problem and any new observations [1], then testing
2.
by jpap 6y ago
Unfortunately not when you're performing error diffusion, where the residuals are added to neighboring pixels. If you're doing it in the non-linear domain, you're going to get a different result during that diffusion step, e
3.
by jpap 6y ago
When I referred to "logarithmic domain", I'm not talking about a purely log/exp transfer function, but one that is "log like". Perhaps it is more accurate to say "non-linear domain"... but I hope you
4.
by jpap 6y ago
This post covers a topic I've spent some time with in the past, and is generally a good overview but unfortunately gets the idea of "linear RGB" wrong. That means all of the results need some attention, including the Go impl
5.
by jpap 8y ago
I'd also love to read the thesis, especially to see how they structured the lock. I recently wrote a readers-writers (subtree) lock for a K-ary tree and it was quite a challenge with a nontrivial implementation. It was much easier to
6.
by jpap 9y ago
They would likely get another big speedup by doing this. iDCT gets faster as you perform a "DCT downscaling" operation because you require fewer add/mul [1]. You could probably go for another speedup, independently of DCT do
7.
by jpap 9y ago
> TIFF and Exif (which JPEG is based on) are not tied to any particular codec and are extensible, so HEIF is not a game changer. TIFF is a great format but its ability for extensibility is limited. You can't readily contain in a vi
8.
by jpap 9y ago
> This format doesn't really blaze new ground (EDIT: it does in the sense that it defines a container format to express image-y constructs like still images and sequences of images in an ISO media container, but see my other comment
9.
by jpap 9y ago
> I'd be curious if the two "representations" are losslessly convertible, for example. They are: you could just extract the HEVC NAL units, and re-write them into a MP4 or QuickTime container, making sure to properly place
10.
by jpap 9y ago
That's actually not a bad idea! The HEIF examples on the Nokia HEIF site do something similar; they implement a HEVC decoder (and do the HEIF container processing) all in JavaScript using http://www.libde265.org . The image
11.
by jpap 9y ago
While the full standard text and machinery can get quite complex, you can still construct relatively simple files housing a single image, thumbnail, and Exif that isn't that much more complex than a typical JPEG file. Compared to JPEG
12.
by jpap 9y ago
Yes! This is one of the motivations behind HEIF: it's codec agnostic and extensible. You can use HEIF with JPEG and AVC for example, or some new codec down the line. It's also extensible, in that you can define new item types and
13.
by jpap 9y ago
HEIF is actually very closely related to MP4 (or really, the ISO Base Media File Format (BMFF); and historically, QuickTime which is what they are both based on). You are right -- the main difference is that BMFF was originally designed for
14.
Responsive background images with JavaScript(jpap.org)
5 points by jpap 9y ago|0 comments
15.
Responsive background images with JavaScript(jpap.org)
1 points by jpap 9y ago|0 comments
16.
by jpap 9y ago
My reference to "awesome" was in the sense of being fun. You could, of course, use a highly-compressed video instead, as some other sites do. Further, Disqus puts this animated GIF on their 404 page, which should, if everything go
17.
Responsive background images with JavaScript(jpap.org)
2 points by jpap 9y ago|2 comments
18.
Optimal positioning of website backgrounds(jpap.org)
3 points by jpap 9y ago|0 comments
19.
by jpap 13y ago
Michael, thanks for making contact by e-mail, outside of these public forums. As discussed over e-mail, I've created an in depth report showing that SnappyCam indeed takes full quality 8 Mpx shots on the iPhone 5. With the amazing disc
20.
by jpap 13y ago
I'm so very happy to read your post! :-) I'm not usually one to post publicly either, but with practice I'm finding it comes more naturally. I do hope you dive in---the devil's details in image signal processing is reall
21.
by jpap 13y ago
I considered doing this over a year ago. I was really intrigued by the algorithm and declared it was a distraction over getting the basic app solid first. I'd love to revisit it. It really works wonders. I've played with the CL
22.
by jpap 13y ago
Agreed! I've got a good friend who is a skater and he reminds me of this often. Any good skating sites I might want to contact?
23.
by jpap 13y ago
That really helps, thanks for letting me know about the disconnect extension. I've never used it, will check it out.
24.
by jpap 13y ago
Very well said. I suspect Clarity on Camera+ is some form of Contrast Limited Adaptive Histogram Equalization (CLAHE). CLAHE came about from digital image cleanup of medical scans for human analysis.
25.
by jpap 13y ago
The Camera Roll will apparently host them, but not show them as animated. Unless you roll your own viewer, many devs suggest using an embedded UIWebView to animate it. Otherwise it kinda gets treated as pass-through for most of iOS. The Me
26.
by jpap 13y ago
Awesome. If you type in your number as if you were local, do you get the iMessage? (Internally I add the international prefix. As you can imagine it took a while to find all of the local prefixes and create number masks!)
27.
by jpap 13y ago
What version(s) are you on? I spent a lot of time checking in more recent versions of FF after developing the site. I do pretty much everything on OS X these days, but I did fire up a couple of VMs with Win XP, Win 7, and Win 8 to test. I
28.
by jpap 13y ago
Oi oi oi! :D
29.
by jpap 13y ago
There's definitely improvements being made to LLVM to automatically parallelize code (esp unrolling loops) to SIMD. I haven't personally tried it, but would love for it to match the code quality of hand-cranked assembly... writing
30.
by jpap 13y ago
Hey @jlebar, you're right--it's existed on the desktop for some time (MMX, SSE). When I first started, libjpeg-turbo never had an ARM port, which was part of the motivation to do it myself. See my post in another thread here on t

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