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Audio API Quick Start Guide: Playing and Recording Sound on Linux, Windows, FreeBSD and macOS

Programming *C *Development for Linux *Development for Windows *Sound
Tutorial

Hearing is one of the few basic senses that we humans have along with the other our abilities to see, smell, taste and touch. If we couldn't hear, the world as we know it would be less interesting and colorful to us. It would be a total silence - a scary thing, even to imagine. And speaking makes our life so much fun, because what else can be better than talking to our friends and family? Also, we're able to listen to our favorite music wherever we are, thanks to computers and headphones. With the help of tiny microphones integrated into our phones and laptops we are now able to talk to the people around the world from any place with an Internet connection. But computer hardware alone isn't enough - it is computer software that really defines the way how and when the hardware should operate. Operating Systems provide the means for that to the apps that want to use computer's audio capabilities. In real use-cases audio data usually goes the long way from one end to another, being transformed and (un)compressed on-the-fly, attenuated, filtered, and so on. But in the end it all comes down to just 2 basic processes: playing the sound or recording it.

Today we're going to discuss how to make use of the API that popular OS provide: this is an essential knowledge if you want to create an app yourself which works with audio I/O. But there's just one problem standing on our way: there is no single API that all OS support. In fact, there are completely different API, different approaches, slightly different logic. We could just use some library which solves all those problems for us, but in that case we won't understand what's really going on under the hood - what's the point? But humans are built the way that we sometimes want to dig a little bit deeper, to learn a little bit more than what just lies on the surface. That's why we're going to learn the API that OS provide by default: ALSA (Linux), PulseAudio (Linux), WASAPI (Windows), OSS (FreeBSD), CoreAudio (macOS).

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The Significance of In-app Messaging Applications in your Digital Business

Instant Messaging *Development of mobile applications *API *Software Video conferencing

In-app messages are targeted notifications sent to customers/ users while they are active on the website or mobile application. They are a very effective way to engage customers as they are already within the application looking for specific information. In-app chat applications help connect better with the users and improve user retention as they are timely and targeted. 

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Android for electronics design engineers

CAD/CAM *Circuit design *Manufacture and development of electronics *DIY Electronics for beginners

There is a list of well-known electronics design tools for Android which can be found in every review for the last 10 years: “Electrodoc”, “Every Circuit”, “Droid Tesla”, “Electronics Toolbox”, “RF & Microwave Toolbox” and so on. Also, there is a lot of trash on the market that turns finding a good tool into a quest.

This short review is about an unknown but cool tool “Circuit Calculator” working on Android devices and intended for professional electronics designers.

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Total votes 4: ↑4 and ↓0 +4
Views 731
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Riddles of the fast Fourier transform

Programming *Algorithms *Mathematics *Sound Visual programming *
Tutorial

• The method of phase-magnitude interpolation (PMI)

• Accurate measure of frequency, magnitude and phase of signal harmonics

• Detection of resonances

The Fast Fourier Transform (FFT) algorithm is an important tool for analyzing and processing signals of various nature.

It allows to reconstruct magnitude and phase spectrum of a signal into the frequency domain by magnitude sample into the time domain, while the method is computationally optimized with modest memory consumption.

Although there is not losing of any information about the signal during the conversion process (calculations are reversible up to rounding), the algorithm has some peculiarities, which hinder high-precision analysis and fine processing of results further.

The article presents an effective way to overcome such "inconvenient" features of the algorithm.

Read in Russian

Read in English
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Analysis of UE5 Rendering Technology: Nanite

Game development *Game testing *Game design *AR and VR Games and game consoles
Tutorial

After Epic released the UE5 technology demo at the beginning of 2021, the discussion about UE5 has never stopped. Related technical discussions mainly centered on two new features: global illumination technology Lumen and extremely high model detail technology Nanite. There have been some articles [1 ][2] analyzing Nanite technology in more detail. This article mainly starts from the RenderDoc analysis and source code of UE5, combined with some existing technical data, aims to provide an intuitive and overview understanding of Nanite, and clarify its algorithm principles and design ideas, without involving too many source code level Implementation details.

 

https://blog.en.uwa4d.com/2022/02
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Introducing into calamares bootloader

Configuring Linux *Open source **nix *Development for Linux *Software
Tutorial


Overview


Sometimes all of us need to make a graphical installer for one's own linux distro. It goes without saying that you are able to use a distro-specific installer like Anaconda for RedHat-based or DebianInstaller for debian-based. On the other hand Calamares is a graphical installer which is not aligned with only one package manager.


I want to share my experience how to make a universal install solution with GUI. I did not find any complete article about it, hence, I reinvented the wheel.

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Total votes 2: ↑2 and ↓0 +2
Views 1K
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UE5 Lumen Implementation Analysis

Game development *Game testing *Game design *AR and VR Games and game consoles
Tutorial

Lumen is UE5’s GI system, it is different from the traditional real-time GI which only includes the contribution of indirect diffuse reflection. It also includes indirect diffuse reflection and indirect highlight, providing a new set of complete indirect lighting. Lumen supports both hardware-based RTX and software-based Trace algorithms. The starting point of this article is that Lumen GI uses the process, algorithm, and data structure analysis of indirect diffuse reflection part based on software Trace to understand the basic principle and operation mechanism of Lumen from a macro perspective.

 

The core of Lumen includes the following parts:

Read more https://blog.en.uwa4d.com/2022/0
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Unity Performance Optimization Ⅵ: Resource Memory Leak

Game development *Game testing *Game design *AR and VR Games and game consoles
Sandbox

Today, we will share some knowledge points related to resource memory leak. A memory leak is the most common issue that we continuously see and also are afraid of. What is the reason behind it? Because we can’t predict the extent of the leak before we locate the leak bottleneck, we had no idea whether it will burst out at a certain moment on the line. We have received feedback from developers that their players had no problem playing for half an hour, but they would get more and more stuck after 3 to 4 hours of playing, which they never expected before. How can it be solved? Today’s sharing will answer such questions.

UWA’s GOT Online-Assets report has a resource occupancy trend chart. If there is a rising trend like the one below, you must pay special attention.

Read more at blog dot en dot uwa4d dot com
Total votes 1: ↑0 and ↓1 -1
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The Cryptocurrency Bandwagon

Decentralized networks Cryptography *Cryptocurrencies

The spread of cryptocurrencies contributed to the development of many solutions based on a distributed ledger technology (blockchain). Although the scope of these solutions varies, most of them have the same basic set of security services, i.e. confidentiality, authenticity, and integrity. These features are granted by the practical applications of public key cryptography, in particular,  digital signature (DS). But unlike many other applications of public key cryptography, cryptocurrency networks do not use public key certificates. This is the aspect that we would like to talk about.

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Monocrystalline solar cell simulation

Energy and batteries

In the green energy field, the solar panels composed of bendable solar cells tend to significantly increase in popularity last time. The difficulty during the designing of the different devices (such as solar chargers, MPPT-controllers) emerges because of the strong lack of technical information about this kind of solar cell.  

In this article, the equivalent scheme of the bendable solar produced by the Sunpower company - Maxeon gen 5 and its coarse simulation model is proposed.

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Music on the Commodore PET and the Faulty Robots

Abnormal programming *Assembler *Demoscene Old hardware Sound

After completion of the System Beeps, I wasn’t planning to make another stand alone album release with the pseudo polyphonic music, as I felt the topic had been explored enough. This, however, wouldn’t mean I couldn’t apply the experience and skills gained to make more utilitarian stuff, like an actual retro game OST or an old school demoscene project. Such an opportunity arose in Autumn 2020, as David Murray of The 8-bit Guy Youtube channel fame announced his new game to be in development, the Attack of The PETSCII Robots for Commodore PET and some other Commodore 8-bitters. As I previously worked with David on his previous big release, Planet X3 game for MS-DOS, and this was a perfect opportunity to satisfy my interest towards the pre-graphics era PCs as well as apply my vast experience both in the minimalistic computer music and 6502 assembly programming, I offered my services that had been accepted. Besides the sound code I also had hopes to participate as a music composer this time.

Unfortunately, this time the project didn’t went well on my side, and lots of issues of all kinds eventually turned it into a small scale development hell (you can learn more from a series of posts at my Patreon blog)  The end result was that my code and sound effects were only used in the VIC-20 port, and music for other versions has been created by other people. However, I was left with the full working code of the sound system for PET, and a number of music sketches. It would be a pity to file it into the archive, PET projects aren’t a frequent thing these days, so another chance to use the stuff wouldn’t come any time soon. So I got the idea to develop my music sketches into full songs, and release it as an alternative OST, and having David’s approval it has been done and released in the Winter 2021 as Faulty Robots, a small music album for PET that is available as a digital audio release and a runnable program for the actual PET computer.

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Total votes 5: ↑5 and ↓0 +5
Views 980
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How to Build a Cryptocurrency Exchange App in 2022

Development of mobile applications *Cryptocurrencies

Do you plan to start a cryptocurrency exchange business? If so, now is the perfect time. The easiest and safest way to make money from cryptocurrencies is to create a crypto-exchange application. Regardless of whether traders and investors make or lose money, the cryptocurrency exchange will remain a winner in any case.

But, how to open a cryptocurrency exchange app? So, let’s look at the main stages of the process.

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Total votes 1: ↑0 and ↓1 -1
Views 2.6K
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“FPGA InsideOut” – animation about CRC and parallel CRC calculation

Open source *FPGA *Programming microcontrollers *Manufacture and development of electronics *Electronics for beginners

Ссылка на русскую версию / link to Russian version

FPGA InsideOut is an attempt to make a set of educational FPGA videos presented in the “human-in-the-loop” style. In these videos we will not only show how we are interfacing with an actual FPGA board but will also provide synchronous real-time visualisation of FPGA's internal logic.

For our first video we have picked a CRC circuit (cycle redundancy check) which is based on a linear feedback shift register. This circuit goes through several transformations during the course of the video. Intrigued? - let’s watch the video.

Watch the video and continue reading
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A new writing method/technology (“dendrowriting”), as exemplified by the YearVer site

Language localisation *Brain

Several years have passed since the appearance of the first text markup language that supports “dendrowriting”, but no worthwhile piece of text demonstrating the advantages of the new writing method/technology has yet appeared.

The largest “dendrotext” was a couple of paragraphs in the pqmarkup documentation, consisting of only ~1300 characters and available only in Russian.

In English there was no “dendrotext” at all, as such [apart from small insertions in the documentation for the 11l programming language (e.g., ‘Boolean type’ in Built-in types)].

But last year...
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IT risk management

Information Security *Development Management *Project management *Finance in IT
Translation

When you have an IT, which supports all aspects of your organization automated performance and you have a firm confidence that IT executes well, there is always a chance that something could go wrong in technology or in related IT processes. Depending on complexity of IT environment varieties of risks scenarios could arise. This article as a summary of different faithworthy sources aims to help you in getting high level understanding on what could go wrong and how you can predict it in a more conscious way.

My name is Max Tornov and I have been working in various IT areas for a long period of time, since then, for over 13 years I am working in the area of IT risk management with specialization in IT audit and internal control effectiveness assessment.

I am sure that at the present the topic of Information Technologies risk management became more vital. Organization’s efficiency in IT risk management directly affects the achievement of various organization’s goals, goals which have dependency on IT, those goals may include reliability and efficiency of business processes, the organization's compliance with regulatory requirements, the integrity of financial reporting, and many others.

I sincerely hope that this material will be useful to you and may give you some new ideas that you can contribute to the benefit of your personal development and the development of your organization's risk management culture.

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Total votes 2: ↑2 and ↓0 +2
Views 784
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