I'd like to grab a frame from my MacBook Pro iSight in C++ and do some elaborations on it.
I already know how to do that in ObjC with QTKit, but is there any way to do the same thing in C++?
NOTE:
I tried to install OpenCV with macports, but the framework doesn't seem to support iSight cameras.
You could do that using OpenCV ( http://opencv.willowgarage.com/wiki/ )
And here is a sample code you can copy/paste to try it : http://www.geckogeek.fr/lire-le-flux-dune-webcam-camera-video-avec-opencv.html (article in french but code is in english)
You can also use the Integrating Vision Toolkit (http://ivt.sourceforge.net), which supports Mac OS X and Quicktime.
Here are the steps:
Install the Quicktime SDK, if you haven't yet.
Download the current version of the IVT and unpack the archive.
Set the flag 'USE_QUICKTIME = 0' to 'USE_QUICKTIME = 1' in IVT/src/Makefile.base
Run 'make' in IVT/src
Run 'make' in IVT/examples/CaptureApp
Run '../../files/make_app.sh CaptureApp captureapp' in IVT/examples/CaptureApp
Run the application, either by double clicking on the generated icon, or by typing 'open CaptureApp.app'.
If you have any questions, let me know (you can find my contact information on the IVT homepage). I also answer questions in the IVT Sourceforge forum usually quite fast.
Related
I installed XCode and opened a new project using SwiftUI but for the following reason it is impossible to run the builded application. I did use the default code and press run.
I get the following message : "minimum deployment target. Change your project’s minimum deployment target or upgrade MacBook ...".
I tried to change the deployement target but immediately I have several Swift Compiler Error like this one : "'some' return types are only available in macOS 10.15.0 or newer"
I'm running a MacBook Pro with 10.14.6. Is there a way to find the source code for a buildable SwiftUI application on my computer ?
I cannot update to 10.15.0 so I'm looking for other advice or explanation. Maybe for some sourcecode I could use on my MacBook compatible with the Swift Compiler I have.
Thanks.
Thanks for your answers. I cannot update my OS and XCode won't build anything if I don't install Catalina first. I was hopping for an other solution, your answers helped me to focus on the right directions so I searched the web a little bit more and read articles on Mac OS X GUI Programming.
I'm now looking at Python : https://wiki.python.org/moin/GuiProgramming
I'm a little bit disappointed because I wanted to start something new with Swift. But, there is a good lesson here, and I'll do with what is possible given what I have :) Back in the days, for GUIs, I've used Web UI, Java and Qt and I was hoping for something new. I guess that I'll pursue my search to create nice and awesome native Mac OS X application both later and on the side.
Thanks.
Firstly, thank you in advance for at least reading this question.
Secondly, feel free to call me an idiot if this is a "no brainer"
Now down to the issue at hand...
I am running Ubuntu 16.04 (64bit) with QT Creator as my IDE and on the whole it works great. I can cross compile for the Raspberry Pi3 (running raspbian) and also compile plugins for X-Plane.
Everything was going great until I needed to implement MySql into my project. That's when it all went south.
I can not use the Qt library for this as X-Plane does not like anything Qt related in its plugins. But that is fine, I have connector-c++ working on that machine and it connects to my MySql server and does everything it's supposed to.
I think I have read just about every forum and watched every youtube video on this but can not get Qt Creator to compile with connector for the raspberry pi.
I wrote/compiled a test app locally (with g++) on the pi and it works great. However for some reason (government plot maybe?) it refuses to link the libraries when compiling under Qt Creator.
The error I get when compiling in QtCreator is:
undefined reference to `get_driver_instance'
Currently,
I have followed the instructions for setting up a cross compiler here:
https://wiki.qt.io/RaspberryPi2EGLFS
Downloaded the connector code from here:
git clone https://github.com/mysql/mysql-connector-cpp
I have followed the instructions for compiling connector-c++ here:
https://dev.mysql.com/doc/connector-cpp/en/connector-cpp-installation-source-unix.html
And I have banged my head 1000x on a brick wall here:
(picture of blood stained wall not available)
Also, I have tried compiling connector on my Ubuntu pc with paths to the pi's sysroot etc. but i think it made a 64bit version which causes Qt Creator to have a dummy spit about "unrecognized format".
I am hoping that this is just me having a "senior moment" and that someone can point me in the right direction.
To save putting up irrelevant logs/code I will wait until someone asks for it and then copy/paste what they need.
Again, thanks in advance and know that I will be eternally grateful for any light on this matter (preferably before I go even insanerer)
Well after 2 weeks of pain, I have solved this problem. Here is what I think is the issue:
Firstly, I found that mysqlcppconn is not needed (at least for me) and used the mysql libraries in /usr/lib
Secondly, the symlinks to libmysqlclient.so.6.0.22 were by default:
libmysqlclient.so.6 -> libmysqlclient.so.6.0.22
The compiler was looking for libmysqlclient.so which didn't exist. So I created the link (libmysqlclient.so -> libmysqlclient.so.6) and it worked!!
Thanks to all who helped.
I'm using Debian Jessie and dmesg | grep video returns:
[ 22.280407] Linux video capture interface: v2.00
[ 22.790704] uvcvideo: Found UVC 1.00 device Lenovo EasyCamera (13d3:5170)
[ 22.796546] usbcore: registered new interface driver uvcvideo
The example compiles fine but upon launch i get a dialog telling me that the camera service is missing. I'm using Qt 5.5.0. This question points to a similar issue but it's for windows. Also I've installed Qt using the installer provided at it's web site. I've tested my webcam with Cheese application and it works but QCameraInfo::availableCameras() returns nothing.
I don't know if this is a definitive answer, but in my experience the dreaded "camera service is missing" comes down to exactly what the message says; for some reason the media back-end that Qt uses to get video input from a camera is broken or miss-configured in some way. In my case I had this problem in the following situations:
1. Building Qt from source
Qt build system SILENTLY DISABLES FEATURES if you don't have all the dependencies that it requires to include them in the build. Make sure to read this official article very carefully for your platform. I lost count of the times this has ruined my <insert favourite period of time such as day/week/year here >, and not only for the multimedia module...
2. Missing some gstreamer packages on my Ubuntu
I develop for Linux & Debian mostly, and on those platforms Qt depends on gstreamer backend. gstreamer is basically a plugin architecture in the core with every single feature added as plugins, and with endless possibilities of manual intervention through configuration files. See where is this is going? Clue: make sure you have all the plugins you want installed and configured properly. Here is a link to some gstreamer tools you can use. Same probably goes for other back-ends on other platforms.
And a pro tip in the end: Since both Qt5.5 gstreamer0.1 (old) and gstreamer1.0 (new) are supported as back-ends, and since Qt5.6 the new one is default. This will give you some room for experimenting, for example if the old does not work, you can try the new etc.
Hope this was useful!
I have a project built using Qt5 which has to play a video. Just like in the videowidget sample code.
I've followed these instructions to build qt5 on my Pi. And it went just fine. But when I try to run any qt program that uses QMediaPlayer, I get the error message:
defaultServiceProvider::requestService(): no service found for - "org.qt-project.qt.mediaplayer"
Which means I don't have a backend to play the video, right? Is there any one that I can use which will with Qt, like ffmpeg? And how can I get it to work? Specially for h264 videos.
I've tried to install gstreamer as is told on this link, but it's not working. Will I have to rebuild the entire qt5 again?
P.S.: I have the raspberry pi 1 model B with raspbian installed.
Edit: As mentioned by Greenflow, I checked the ./configure log and saw that the GStreamer was compiled in, but the video apps are still not working...
The message on the log was like this:
GStreamer .............. yes (0.10)
And the message on Greenflow's log was like this:
GStreamer .............. yes (1.0)
Clearly it's another version of GStreamer, but is it the problem?
I've also found this post which says QtMultimedia on the Pi is rather useless, but the post is from 2013, so I'm not sure if it's really relevant. I'd like to have this app playing hardware accelerated videos on my Raspberry Pi, but I'm almost dropping the idea.
Anyways, thanks Greenflow for the head start.
Edit 2: Found this thread on the Qtcentre. Damn, this thing is not going to be easy to solve, I guess...
sudo apt-get install libqt5multimedia-plugins solved this for me.
I just don't seem to be able to get OpenCV to work properly. Here's what I want to accomplish:
Use CodeBlocks (which I installed using codeblocks-10.05mingw-setup.exe) with OpenCV (installer: OpenCV-2.4.2.exe) on my Windows x64.
I've tried a lot of different configurations which will only bother you if I posted them all, so I hope you don't mind if I just ask the simple question: how do I get this to work?
I think I'm missing the smallest detail right now, so a detailed description of how to get started would be welcome.
If the OpenCV installer did the job, you should have by now OpenCV libraries and headers already installed in your system.
I would then go ahead and try to compile a hello world basic code, like the one you can get from here. If you would like to program using an IDE, like VisualC++ in Windows, you can follow this guide that will help you setting up the environment.
OpenCV team just introduced their new web site. There you can find Introduction to OpenCV section with installation instructions, including detailed instructions for Windows. Don't forget to cleanup your system before installation to avoid problems with mixing different install options. If you still can't get it working with CodeBlocks, follow Dan's advice and try compiling from command line.
When you are done with installation, go on and read there great new tutorials!