Can anyone suggest a good audio QOS monitoring tool?
If its a open source one and freely available, it will be great. Its fine otherwise too.
Iam trying to measure QOS for a softphone on a PC and also on a mobile.
Try the following link and search for QoS: http://www.slac.stanford.edu/xorg/nmtf/nmtf-tools.html
Bear in mind that a users perception of the quality of a voice call is not an absolute thing so treat any results with this in mind. See: http://en.wikipedia.org/wiki/PESQ for one way (probably the most accepted way) to measure and score voice quality.
You can measure absolutely the delay and packet loss which may give you the information you need.
We have developed a tool for Measuring QoS for both Audio and Video and have some patented algorithms to find out the MOS for Video and used E-model for Audio MOS.
It has been tested on VoIP calls over LTE.
You can check one more tool from EMpirix called Hammer Call analyser or any Elecard tool as well.
But i don't know of any freeware tool in this domain.
I have done voice quality monitoring system for conferencing services provider. Tools used: Empirix Hammer and CallMaster. System in a nutshell: every so often two virtual participants called into conference call. Then each of them spoke a phrase and the other one measured PESQ score. Results were sent to another monitoring system. This worked well. I think PESQ measurement is the way to go for automated testing.
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We know that when we playe videos, there is usually a compensation for the latency of audio output device, to synchronise the sound and pictures.
To achieve this, one must have some way to know the value of the latency.
How is that achieved? Is there a portable api to get this value? This sounds very simple, but after searching a bit, I have not found anything. Latency is a complicated issue, but such an api should tell us about at least part of the latency. (If it is hard to find portable api, then platform-specific apis are also fine.)
It would be really helpful if I can find a simple demo implementation of a media player with latency compensation.
An article on Hackaday piqued my curiosity, and I see Kinect + Linux questions being asked here (mostly about configuration), so I'll venture this question:
It is clear to me that Kinect can be used together with Linux on a "regular pc" -- but I can't help wondering why, that is, what might you actually use this for?
I don't suppose people really like the human/computer interface presented in movies such as "Minority Report" -- surely, nobody is actually doing text editing, coding, or business data processing by "hand-waving". So besides just games & exercises, what are examples of actual, real-world, useful (ie. 'professional') applications of such a setup?
For instance, can it be used for 3D scanning of real-world objects to obtain digital models? What sort of accuracy would such a scan yield?
The Kinect can be used for a wide variety of useful applications. I'm not sure if you are asking specifically about Linux or if Windows ("regular PC") is acceptable, but I'll provide you with some examples that come to mind.
For Linux specifically, it is likely that applications on Linux are using the sensor's raw sensor data only, rather the skeletal tracking feature. Many Kinect applications are on Windows because Microsoft's Kinect SDK is available only on Windows, and it provides the best skeletal tracking accuracy to-date.
You are right that the Kinect is rarely used where a keyboard & mouse would be faster and more accurate, but note that it is potentially relevant for accessibility.
And yes, it can be used for 3D scanning of real-world objects. I'm not sure about the exact accuracy, but I think it is acceptable for many applications. The main benefits are its low cost and speed.
For examples of 3D scanning, check out:
KinectFusion, a Microsoft Research project
Occipital Structure sensor for 3D scanning. (This is not the Kinect sensor, but provides an example application for 3D scanning. The company has a Kinect-related history as well.)
Styku - 3D body scanning for clothes fitting
Aside from 3D scanning, here are some other examples of applications:
Atlas5D - at-home patient monitoring
GestSure - 'Minority Report' interface for surgical rooms
Jintronix - games, exercises, assessments for physical therapy
There are many depth sensors like the Kinect3D on the market. The latest notable application would be iPhone X's depth sensor and FaceID. Many companies in the space are working actively in FaceID now, which would also be useful on Linux. Check out Microsoft's Window Hello biometric facial ID system - see Microsoft's official website:
Manufacturing of the Kinect sensor and adapter has been discontinued,
but the Kinect technology continues to live on in products like the
HoloLens, Cortana voice assistant, the Windows Hello biometric facial
ID system, and a context-aware user interface.
Kinect has applications in the robotics community as well, though I don't know the specifics. I assume many in robotics community use Linux when working with the Kinect. The depth and color cameras can be used to provide vision and the microphone array for audio input.
Generally, the Kinect had a big impact when it was released not just because of its technology but also because of its low price point, even if it's not the most accurate for every application. As this technology improves, I hope many other applications will emerge and become mainstream.
EDIT: also, check out this Hacker News discussion: "Microsoft Has Stopped Manufacturing The Kinect"
I have a couple of questions concerning BLE beacons:
1) Are beacons based on nRF51822 chip the best solution? Or are there any other chips better than nRF51822? I want to take up BLE beacon development and struggling to find the right hardware for these needs. As a novice developer I want the beacon to be as cheap as possible in order not to waste money in case of a failure.
2) Is it possible to buy pure Eddystone beacon (not iBeacon)? The reason for choosing Eddystone is that Eddystone is capable of broadcasting URLs that are essential for me.
The second question stems from my failed attempts to find a pure Eddystone beacon on Chinese electronics sites like alibaba.com or aliexpress.com where the only firmware available is iBeacon. But iBeacon is not an option because it can't broadcast URL the way Eddystone does.
Apart from the above questions It would be great if someone wrote a quick guide for taking up BLE development with Eddystone and covered basic topics like: chip to use, beacon model, best website to buy beacons at, etc.
Thanks in advance,
Pavel
1) I've worked with Estimote beacons and Chinese beacons from Amazon and in my opinion, they do not differ in terms of accuracy too much. Especially for prototyping, I'd buy cheaper ones to test if your use case can be satisfied with BLE beacons. If it is too inaccurate with Chinese beacons, chances are that it won't work with more expensive ones either.
2) Why do you need the URL broadcast? If the app is going to use the url, it would have to be connected to the internet. Therefore, you can just query the beacon's IDs to a web service to get back an URL and use that. Personally, I think this is a better approach as you can configure the web service from anywhere to change the url for beacons where as if you want to change the URL of the Eddystone, you have to go to the beacon to configure it.
The nRF51822 is a common implementation, is flexible, well understood and can be very inexpensive. Be aware though that development costs, add on circuitry for power and/or peripherals, and packaging can easily eclipse the Bluetooth chip when you get to production cost savings.
If you want to buy an off the shelf beacon, most models supporting Eddystone also support iBeacon, simply because supporting both adds no additional hardware cost. Newer Radius Networks and Estimote beacons all support both. And, yes, cheaper generic Chinese suppliers often have bulk manufactured inventory from before Eddystone existed at only support iBeacon.
So far, I've used many different Audio Production software on Mac and Windows platforms. Often times, I ponder on the idea of creating my own DAW, but I realize that would be an extremely difficult challenge for a single person to undertake (especially if only knowledgeable in one particular area / language of programming).
There's a flood of ideas / features that comes to my mind just by the thought of some of the other DAWs I've used. From implementing MIDI in/out, Audio Routing, Mix Buses, VST support, User Interface for a Piano Roll and Song view, etc...
So my question is...
Which roles would be required in a team of developers to create a complete Digital Audio Workstation (DAW) Software?
I think the right answer is several good developers (you don't need so many, perhaps 3) a good product manager, an ui designer/graphist a lot of testers. And a good coffee machine.
The real problem is what kind of DAW do you want, portable on mac and windows, which OSs, which formats (vst 2, 3, AU, RTAS, AAX, rack extension, DX), do you want only MIDI and adio tracks, which external MIDI devices you want to support, do you support OSC, other protocols?
What will be the features of you mixer, integrated effects? What support of audio API on windows (wasapi, asio ...) do you want some cloud feature ? community or online store integration?
What kind of breakthrough would you have compared to cubase, live, PT, DP, Logic, garage band, bitwig, studio one, sonar, fl studio ...? Do you want modular patches or just tracks? Will you have advanced integrated controls or midi modifiers?
All that is the problem...
This is a very complex question!
which API or library on which mobile OS is to be used when one needs to write a code to use the phone's IrDA to create the necessary impulses to remote control consumer electronics e.g. a HDD media player?
Is maybe a certain mobile OS better suited for that kind of application than others?
First you need to know that IrDA is not the best choice for remote control. It can be done, but IrDA is by design high speed/low range, you can emulate low speeds but ranges (IMO) are far from practical usage (Nokia e50 is able to control digital camera shutter from 2-3m... with very, very careful aiming). The amount of hacking needed to achieve this is shown here, you basically need to trick IrDA to send correct impulses with correct frequency.
The second thing is that CIR remote control is not as simple as you might think. There are countless standards that differ in used frequency, modulation, wavelength, command codes and so on. You need to know what you want to support. LIRC site can be very helpful in determining that http://lirc.sourceforge.net/remotes/. Approachable explanation of what it all means is available here: http://www.sbprojects.com/knowledge/ir/ir.htm
As for ready made libraries and platforms... I honestly don't know. I've seen it done on PocketPC (nevo among others) and Symbian S60 (irRemote). Haven't seen working J2ME app yet.
Last time I needed the IR remote I hacked it together using IR diode, AVR ATTiny and surprisingly short piece of assembly :)