I'm trying to get the video feed from usb camera attached to my Raspberry. Since it's not the dedicated one I can't just use raspivid or the raspicam that comes with uv4l to make changes to config that actually gives some effect at contrary to v4l2-ctl.
When I connect to the WebRTC server through the browser client it actually works at decent framerate. I don't yet understand how that technology works, but before jumping into it I was wondering if someone could tell me if it's possible to somehow (with client made in python or some other opencv magic) get that video feed.
Thanks in advance
I'm still interested if what I've talk about is possible, so if anyone with knowledge stumbles upon this thread, please let me know.
I've kinda solved my issue by using the mjpg-streamer experimental instead, it can be found here:
https://github.com/jacksonliam/mjpg-streamer
Now I'm getting over 8 fps, but it seems much more constant and really seems like I don't need more, compared to uv4l that gave me 3.5 fps with stutters.
Related
So i had been making video tutorials for my friends on how to program. On my old computer i had been all ways running simple screen recorder and it recorded fine. But recently i got a new computer. And so when i got a fresh install of arch linux on the box. I set up the environment with every thing i needed to make another video. When i downloaded simple screen recorder using yaourt, and started recording. I had recorded up to a two hour session with out knowing that it was glitching out. When i look at my computer i do not see the same issue as when the final product is done rendering. I think it might be a rendering error or i do not have the right codecs. After a hour or two searching on the web i could find no forum posts on the codec. I took in multiple things that could be wrong with it fps was my first choice but when i had recorded with 25 and even 50 fps it was still glitching out. The next idea i had was that i had the wrong codec H.264. But with searching i could find no solution to that one. Then i thought that i might have been encoding at to high of a speed (23). But still that proved me wrong. so now i am confused with how to get my answer.
Settings Screen shot:
Video Link:
https://www.youtube.com/watch?v=zfyIZiJCDa4
The glitches are often relate to the rendering backend of the window compositor you are using.
Solution 1 - Change the rendering backend of the window compositor
#thouliha reported having issues with compton. In my case I had glitches with openGL (2.0 & 3.1) and resolved the issue by switching to XRender for recording.
On KDE you easily change the rendering backend of the window compositor in the settings .
Solution 2 - Change the Tearing Prevention method
To keep using OpenGL, for example for better performance, you can also tweak the tearing prevention method.
In my case switching from Automatic to Never allowed me to record video with OpenGL compositor without glitches.
Solution 3 - Intel iGPU specific issues
Intel iGPU (Intel graphics) has some rendering issues with some CPUs.
You can check the Troubleshooting section of ArchLinux wiki to check those.
Example of features creating tearing or flickering related issues:
SNA
VSYNC
Panel Self Refresh (PSR)
Check also /etc/X11/xorg.conf.d/20-intel.conf if your system has put tweaks in here.
I'm not exactly sure what you mean by glitching out, especially since the video is down now, but I've found that the video is choppy when using compton, so I had to turn that off.
I am building a network utility for OS X. I've gone through Apples documentation, but I cannot find the framework that allows my app to monitor incoming bytes. Can anybody point me in the right direction? Thank you for your time!
To get statistics on a network, you can use the sysctl system call. This is fairly thinly documented; there's another answer on StackOverflow that gives a brief example, and for more detail, I'd recommend looking at the netstat source code.
I think for something like this could be done with
http://www.wireshark.org/ or http://www.tastycocoabytes.com/cpa/
In Linux you could simply listen to the file that is associated with your network card.
But I don't think this can be done an easy way on OS X. But indeed there must be some way, thinking of LittleSnitch.
You can use libpcap, which is a portable library for doing packet captures used by tcpdump, Wireshark, and more. It's not an official Apple library, but it's BSD-licensed so you shouldn't have any problem using it.
I want to read how much data from 3G every app uses. Is this is possible in iOS 5.x ? And in iOS 4.x? My goal is for example:
Maps consumed 3 MB from your data plan
Mail consumed 420 kB from your data plan
etc, etc. Is this possible?
EDIT:
I just found app doing that: Data Man Pro
EDIT 2:
I'm starting a bounty. Extra points goes to the answer that make this clear. I know it is possible (screen from Data Man Pro) and i'm sure the solution is limited. But what is the solution and how to implement this.
These are just hints not a solution. I thought about this many times, but never really started implementing the whole thing.
first of all, you can calculate transferred bytes querying network interfaces, take a look to this SO answer for code and a nice explanation about network interfaces on iOS;
use sysctl or similar system functions to detect which apps are currently running (and for running I mean the process state is set to RUNNING, like the ps or top commands do on OSX. Never tried I just suppose this to be possible on iOS, hoping there are no problems with app running as unprivileged user) so you can deduce which apps are running and save the traffic stats for those apps. Obviously, given the possibility to have applications runnning in background it is hard to determine which app is transferring data.
It also could be possible to retrieve informations about network activity per process/app like nettop does on OSX Lion, unfortunately nettop uses the private framework NetworkStatistics.framework so you can't dig something out it's implementation;
take into account time;
My 2 cents
No, all applications in iOS are sandboxed, meaning you cannot access anything outside of the application. I do not believe this is possible. Neither do I believe data-traffic is saved on this level on the device, hence apple would have implemented it in either the network page or the usage page in Settings.app.
Besides that, not everybody has a "data-plan". E.g. in Sweden its common that data-traffic is free of charge without limit in either size or speed.
Is it possible to capture all/any audio played by a PC into a system.io.stream, so that it can then be run through speech recognition (System.Speech.Recognition.SpeechRecognitionEngine)?
Essentially I'm looking to pefrom speech recognition on any audio on the client PC, google seems to suggest that capturing a stream like this can be done using Microsoft.DirectX.DirectSound, however I cannot honestly determine how. Any suggestions would be greatly appreciated.
Take a look at this question for a solution on Vista/Win7, and take a look at this one for WinXP.
Summary:
You can use Loopback recording with WASAPI in Vista/Win7, but there is no equivalent API in WinXP, however a partial solution can be achieved with a virtual soundcard driver.
I'm looking into writing an app that runs as a background process and detects when an app (say, Safari) is playing audio. I can use NSWorkspace to get the process ID's of the currently running applications but I'm at a loss when it comes to detecting what those processes are doing. I assume that there is a way to listen in on a process and detect what public messages the objects are sending. I apologize for my ignorance on the subject.
Has anyone attempted anything like this or are aware of any resources that can help?
I don't think that your "answer" is an answer at all...
and there IS an answer (which is not "42")
your best bet for doing this would be to write a pass-through audio output device. Much like soundflower, actually. so your audio output device would then load the actual (physical) audio output device and pass the audio data along to it directly (after first having a look at the audio stream, of course!). then you only need to convince your users to configure your audio device as the default audio output device so that the majority of applications which play sound will use it automatically. and voila...
your audio processing function will probably just do a quick RMS on the buffer before passing it along to the actual output device. and when the audio power crosses a certain threshold (probably something like -54dB with apple audio hardware), then you know that some app is making sound.
|K<
SoundFlower is an open-source project that allows Mac OS X applications to pass audio to each other. It almost certainly does something similar to what you describe.
I've been informed on another thread that while this is possible, it is an extremely advanced technique and not recommended. It would involve using Application Enhancer (APE) and is considered a not 'nice' thing to do. Looks like that app idea is destined for the big recycling bin in the sky :)