SOUL Wants To Process Your Audio

January 29, 2021 by Al Williams 14 Comments

Abstraction is the core of nearly all progress in computing. Unless you are fabricating your own semiconductors and drawing wire, we all create with building blocks ranging from components like CPUs, to operating system functions, to specialized libraries. Just as you wouldn’t want to spend your time deblocking disk records or rendering fonts for output devices, you probably shouldn’t have to think too much about audio data. While there are some powerful audio processing libraries out there, a new embeddable language called SOUL (SOUnd Language) is now in version 1.0 and wants to help you create efficient code for processing audio.

The goal of SOUL is to target a runtime that can run on CPUs, but is better on DSPs. The code aims to be secure and real time with no pointers, garbage collection, and other things that typically interfere with audio processing or security.

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Decoding NOAA Satellite Images In Python

January 27, 2021 by Tom Nardi 10 Comments

You’d be forgiven for thinking that receiving data transmissions from orbiting satellites requires a complex array of hardware and software, because for a long time it did. These days we have the benefit of cheap software defined radios (SDRs) that let our computers easily tune into arbitrary frequencies. But what about the software side of things? As [Dmitrii Eliuseev] shows, decoding the data satellites are beaming down to Earth is probably a lot easier than you might think.

Well, at least in this case. The data [Dmitrii] is after happens to be broadcast from a relatively old fleet of satellites operated by the National Oceanic and Atmospheric Administration (NOAA). These birds (NOAA-15, NOAA-18 and NOAA-19) are somewhat unique in that they fly fairly low and utilize a simple analog signal transmitted at 137 MHz. This makes them especially good targets for hobbyists who are just dipping their toes into the world of satellite reception.

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What’s The Deal With Chromium On Linux? Google At Odds With Package Maintainers

January 26, 2021 by Tom Nardi 152 Comments

Linux users are more likely than most to be familiar with Chromium, Google’s the free and open source web project that serves as the basis for their wildly popular Chrome. Since the project’s inception over a decade ago, users have been able to compile the BSD licensed code into a browser that’s almost the same as the closed-source Chrome. As such, most distributions offer their own package for the browser and some even include it in the base install. Unfortunately, that may be changing soon.

A post made earlier this month to the official Chromium Blog explained that an audit had determined “third-party Chromium based browsers” were using APIs that were intended only for Google’s internal use. In response, any browser attempting to access features such as Chrome Sync with an unofficial API key would be prevented from doing so after March 15th.

To the average Chromium user, this doesn’t sound like much of a problem. In fact, you might even assume it doesn’t apply to you. The language used in the post makes it sound like Google is referring to browsers which are spun off of the Chromium codebase, and at least in part, they are. But the search giant is also using this opportunity to codify their belief that the only official Chromium builds are the ones that they provide themselves. With that simple change, anyone using a distribution-specific build of Chromium just became persona non grata.

Unhappy with the idea of giving users a semi-functional browser, the Chromium maintainers for several distributions such as Arch Linux and Fedora have said they’re considering pulling the package from their respective repositories altogether. With a Google representative confirming the change is coming regardless of community feedback, it seems likely more distributions will follow suit.

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Scanner Snooping Uncovers Focus Farce

January 20, 2021 by Tom Nardi 8 Comments

From his comments about the noisy image and limited controls, we’re going to go out on a limb and assume [Andrew Jeddeloh] isn’t a huge fan of using his Epson V550 for scanning film. But is it really irredeemable? That’s what he set out to determine in a recent series of posts on his blog, and from what we can tell, it’s not looking good for the old Epson.

The first post attempts to quantify the optical capabilities of the scanner by determining its modulation transfer function (MTF), point spread function (PSF), and comparing its horizontal and vertical resolution. As you might expect, the nuances of these measurements are a bit beyond the average user. The short version of his analysis is that the scanner’s slide frame does indeed seem to be holding objects at the proper “sweet spot” for this particular image sensor; meaning that contrary to the advice he’d seen online, there’s nothing to be gained by purchasing custom film or slide holders.

While investigating the optical properties of the scanner, [Andrew] became curious about the automatic focus options offered by the VueScan software he was using. The images produced appeared to be identical regardless of what option he selected, and he began to suspect the feature wasn’t actually doing anything. To confirm his theory, he wrote a shim program that would sit between the proprietary VueScan program and the V550 driver and log all of the data passing between them.

After tweaking various options and comparing the captured data streams, [Andrew] determined that enabling automatic focus in VueScan doesn’t do anything. At least, not with his scanner. He did notice a few extra bytes getting sent to the driver depending on which focus options were selected, but the response from the scanner didn’t change. He thinks the program likely has some kind of generic framework for enabling these kind of features on supported hardware, and it’s just mistakenly showing the autofocus options for a scanner that doesn’t support it.

If there’s some film you want to digitize, but you’re saddled with a scanner like the V550, you could always do it with a camera instead. You could even put together a passable film scanner with LEGO.

Old Kindle Shows HDMI Video, Eventually

January 8, 2021 by Tom Nardi 17 Comments

Even with the recent price reductions on stand-alone panels, picking up a used Kindle is still arguably the most cost effective way to get your hands on a large electronic paper display. Especially when you consider the Kindle includes a battery, case, and electronics to drive the display. Bending the Kindle software to your whims introduces its own unique challenges of course, but with a little tweaking, an old e-reader can live again as whatever you wish it to be.

Case in point, the OkMonitor project by [Brendan Sleight]. Using a somewhat dizzying combination of software and hardware, he’s figured out a way to turn an older Kindle Paperwhite into a plug-and-play HDMI monitor. Is it a great monitor? Far from it. As the name implies, the best you can hope to get from this solution is an OK monitor. But at least it’s something.

There’s quite a bit going on behind the scenes in OkMonitor, which [Brendan] describes through a slideshow on the project page. But the high-level idea is that a Raspberry Pi 4 with a simple USB HDMI capture device takes the video input and converts it on the fly to a scaled down Kindle-friendly format. The converted video is streamed over WiFi to the jailbroken Kindle with netcat, where it’s displayed by a native video player. In the video after the break you can see that the end result looks pretty impressive, even if there is a considerable delay involved.

Despite the demonstration [Brendan] has put together for OkMonitor, we can’t say we’d watch many films over this setup. But the fact that you can plug any HDMI device into the “base station” and have the video sent out to one or more Kindles is undeniably impressive. It’s definitely worth a close look, even if you just take some of the concepts of this project to get your own Kindle repurposing idea off the ground.

We’ve recently seen some promising progress made towards repurposing large e-paper price tags labels, but it’s hard to imagine such niche devices will ever become cheaper than second hand Kindles. With continued software development, these old e-readers are likely to remain quite popular among hackers.

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A Fresh Linux For The Most Unexpected Platform – The Nintendo 64

January 1, 2021 by Jenny List 24 Comments

Though it was famously started by Linus Torvalds as “a (free) operating system (just a hobby, won’t be big and professional like gnu) for 386(486) AT clones“, the Linux kernel and surrounding operating system ecosystems have been ported to numerous architectures beyond their x86 roots. It’s therefore not unusual to hear of new ports for unsupported platforms, but it is extremely unexpected to hear of one when the platform is a games console from the mid-1990s. But that’s what [Lauri Kasanen] has done, announcing a fresh Linux port for the Nintendo 64.

This isn’t a Linux from 1996 either. The port builds on an up-to-date kernel version 5.10 with his N64 branch and a tantalising possibility that it might be incorporated into the main Linux source for the MIPS-64 processor architecture. That’s right, the Nintendo 64 could be an officially supported Linux platform.

It would be stretching the story a long way to call this any kind of distro, for what he’s produced is a bootloader that loads the kernel and creates a terminal with busybox loaded. With this on your flashcart you won’t be replacing that Raspberry Pi any time soon, so why other than [Lauri]’s “because I can” would you be interested in it? He supplies the answer and it lies in the emulation scene, because having a Linux for the platform makes it so much easier to port other software to it. If this tickles your fancy you can see the source in his GitHub repository, and we’re certainly looking forward to what the community will do with it.

We are more used to seeing the N64 as a subject for case-modding, whether it be as a handheld or a an all-in-one console.

Via Phoronix, and thanks [David Beckershoff] for the tip.

Header image: Evan-Amos, Public domain.

Number Bases Stretch The Mind

January 1, 2021 by Chris Lott 22 Comments

Some of us might solve crossword puzzles or Sudoko games to exercise our minds, but [Nathan Nichols] plays with exotic number systems to keep the brain cells in shape. He wrote the Hanoi C99 library while in high school, implementing several of his favorites.

We have all been using decimal (base 10) and duodecimal (base 12, as in clocks) since before grade school. Us computer geeks are also adept at various computer-friendly systems like binary, octal, and hexadecimal. The true nerds among us will be familiar with systems like vigesimal (base 20 Mayan numerals) and sexagesimal (base 60 Babylonian numbers). We ourselves espoused the virtues of seximal (base 6) a couple of years ago. But if you really want to stretch your mind, take a dive into the weird number systems that [Nathan] has been exploring.

Negabinary (`base -2`)

The lowest level of weirdness in the group, this one is almost normal. Its the same as binary, except the bit weights have alternating signs: { 1, -2, 4, -8, ... }.

Binarions (`base -1+i`)

Or base -1+j if you studied electrical engineering. The use of complex numbers as radices was proposed by Donald Knuth way back in 1955. We find it really hard to imagine this one being helpful.

Fibonacci base

Numbers can also be represented by the summation of a sequence of Fibonacci numbers. Using this system, a number can sometimes be represented more than one way, so watch out.

Stern-Brocot tree

A number is represented by its path down the Stern-Brocot tree. One feature of this system is that numbers can be exact. For example, the Stern-Brocot tree representation of one-third has a finite number of digits.

While [Nathan]’s library only performs conversion at input or output, we wonder if someone will take this further and implement an arithmetic unit inside an FPGA. Besides being a fun exercise, it would baffle someone casually trying to reverse engineer your secret calculations. Let us know of any strange number systems you have used or encountered.

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