Very soon we are going to work on a project with open source s/w that does many things and one of the modules concerns with capturing live feed from a usb based camera for upto 48 hours and overwriting it in a nonstop loop. This would be going on in parallel with other operations in the application. We also have to display the captured feed of the least 48 hours to the user as a menu option.
I would like you all to suggest a suitable open source technology stack taking into account the audio/video part of the module, without this feature I can definitely use Qt to do my stuff but with this feature that becomes a difficult proposition. I have developed GUI applications with Qt on Linux platform but haven't been able to come up with something that can record and display video in an application. Qt has phonon but setting it up is a nightmare. Earlier some of you had suggest v4linux. I tried to compile the sample program capture.c on RHEL 4 machine and it gave the following errors.
usr/src/kernels/2.6.9-5.EL-i686/include/linux/videodev2.h:436: warning: no semicolon at end of struct or union
/usr/src/kernels/2.6.9-5.EL-i686/include/linux/videodev2.h:436: error: syntax error before '*' token
/usr/src/kernels/2.6.9-5.EL-i686/include/linux/videodev2.h:438: error: syntax error before '*' token
/usr/src/kernels/2.6.9-5.EL-i686/include/linux/videodev2.h:438: warning: data definition has no type or storage class
/usr/src/kernels/2.6.9-5.EL-i686/include/linux/videodev2.h:439: error: syntax error before '}' token
/usr/src/kernels/2.6.9-5.EL-i686/include/linux/videodev2.h:810: error: field `win' has incomplete type
So hit a dead end, besides I haven't come up with concrete workable examples for the same. Also the website isn't being updated frequently suggesting a stagnancy in development process.
Since the application will be graphical with menu based user interaction, it would need to use Qt or something similar to it for the graphical part. The headache is I haven't been able to figure out, how I can implement/integrate the video capture/display feature in a dummy application (my try was with Qt may be some of you have done it with some other library or language).
EDIT:
Was able to compile the program by importing a local copy of videodev2.h and adding define statement to include a __user macro. But now it won't run as it cannot find /dev/video device. So again stuck at a dead end in video4linux
You could try the FFmpeg family of libraries. As of fairly recently (I think), it also comes with the libavdevice library that supports V4L and V4L2 for video capture, and it shouldn't be very difficult to build a FFmpeg pipeline to read video from an avdevice source and write it using avcodec and avformat into a file...
gstreamer is a very capable multimedia stack for capturing, and pygst and PyQt4 bindings exist for use in Python.
If it said "can't find /dev/video", that is because Linux numbers the devices.
If you would have looked in the .c file you would have seen there were several arg_opts
as -d ... (where ... would become /dev/video0) or you can go in the .c file and add a 0 to /dev/video, you'll find it somewhere about line 590 in the beginning of int main.
Related
The title says it all. But, are there too many files to be replaced and is there a risk? What I mean is, there are files like d3d11.dll. Could I replace the files with with something like d3d12.dll or something like that?
When code is compiled it uses 'headers' and usually links to 'libraries' which refer to functions inside the dll. When the game loads it maps the DLL into the address space of the executable so that the program can use features in the DLL.
So if the Game does D3D11_DrawTriangles, it will end up calling that feature in d3d11.dll. Dropping in the DX12 DLL won't work because the expected function is no longer there (and besides, the executable would still be looking for the 11 DLL - it wouldn't even load).
Upgrading from DX11 to DX12 is a major undertaking; the graphics APIs are very different.
Put another way: It's like someone dropped a Fiat engine into your Volvo. Would it work? How much effort would it be to rewire all the pipes and electronics to make it work?
How do I cross-compile a QT application for a Freescale Hummingboard(imx6(arm))?
There are some guides around, but I've not been able to complete one with success.
The following (and more) guides give me a compile error on ./configure
http://forum.solid-run.com/linux-on-cubox-i-and-hummingboard-f8/qt5-3-on-hummingboard-t2072.html
https://community.freescale.com/docs/DOC-94066
When I run the ./configure command (With recommended commands, I've tried this with a lot of possibilities for commands but got none working). I got a compile error for all the external libraries QT uses (zlib, libjpeg, libpng, etc.). So it's a dead end from there.
I've tried a lot more stuff, I don't even remember all the stuff I've tried, but I got nothing working.
I'm trying to use mini-distribution for the Hummingboard. It's a system without window manager that is able to run QT applications (QT5). The build tool I'm trying to use is gcc-linaro-arm-linux-gnueabi, I'm using QT Creator. I've got QT working on the Hummingboard, I just can't compile anything for it.
I managed building an application for the IMX6 finally. Here is how I did it for other's. It's not an optimal solution but it is an solution.
I use Buildgear to build mini-distirbution as OS (Google it, not enough links with my reputation). I append my own application to this mini-distribution to also build it. This is done by placing creating a folder in the buildfiles/cross/cross-hummingboard folder and adding a buildfile (mine look like this http://pastebin.com/bZkJUiry). In this folder I also place a .tar of the project files (including the .pro). To get it to build I add "qt-gui" as a dependency to the fs (buildfiles/cross/cross-hummingboard/fs) by adding it to the list of depends.
I then run buildgear build fs, which will create an (Tarred) image including my (working) qt-application! I then extract the ./qt-gui executable and ssh it to the Hummingboard.
Of course this is all a bit cumbersome so I made a script that automates this all: http://pastebin.com/jFM6rZyY
It copies and Tars sources, compiles it together with the fs, extracts the executable, ssh's the file to the hummingboard and runs it. Takes about 3 minutes building but it works which is what counts for me at this point.
I'm trying to get the PCL Visualizer demo examples to work (all code here: http://pointclouds.org/documentation/tutorials/pcl_visualizer.php) for Windows, PCL 1.6, 32 bits version.
It works fine except for the Interaction Customization part, which is ironically the one i'm most interested on. An unhandled exception occurs at the spinOnce(100) line on the main method. From the long search I've done, it looks like it is deeply connected to VTK not being thread safe and keyboard/mouse callbacks interfering with the VTK window. However, I don't think I've completely understood this and could be mistaken. I have found a very similar question here in stackoverflow (using "pcl::visualization" in different threads from different instance of a class) and I tried using scoped_locks around the spinonce, as he suggests, but I think I'm not doing it right.
Has anyone managed to fully use this example on win32? For reference, here is my poor attempt at locking the spinonce:
while (!viewer->wasStopped ())
{
boost::mutex vis_mutex; //storage for static lock
boost::mutex::scoped_lock lock(vis_mutex);
viewer->spinOnce ();
boost::this_thread::sleep (boost::posix_time::microseconds (100000));
}
Thanks in advance!
I am afraid that it may be related to the version of PCL.
Tutorials are made to match latest versions of PCL and since 1.6 things might have changed.
I recommend you to update to the latest PCL from github. (actually I use code from this tutorial on win64 right out of the box, no issues)
HOW I CAME ACROSS THIS
I wrote code for a simple stopwatch which can also double up as a Rubik's cube timer. The source code and the executable are here:
Cube timer
Anyway my doubt is not regarding this code(It works fine).
I downloaded the executable that I had uploaded to check if it worked fine and at that time I was greeted with this screen:
Open file - security warning
And under this dialogue box there was a field that said:
Publisher : Unknown Publisher
SCREEN SHOT:
DOUBT
Is there some way programatically or otherwise by which I can change the publisher field?
SPECS
I have compiled the code with Microsoft Visual C++ 2010 Express.
You can easily change the publisher, either when linking/compiling by setting the appropriate resources for your project (e.g. CompanyName), or modifying the resources with a resource editor.
Your problem is really that there is no signature, so even if a publisher field is present it cannot be trusted.
You can find an example resource rc file near the end of http://msdn.microsoft.com/en-us/library/windows/desktop/aa381058%28v=vs.85%29.aspx.
To add resources to your VC project check:
How do I embed version information into a windows binary?
VC++ 2012: How to include version info from version.inc (maintained separately) into the .rc file
The .rc file(s) will be compiled to binary (.res) and linked into your final executable.
To add or modify an existing executable, you should be able to use this tool (login required, this will cause the signature to be invalid in an already signed binary of course).
The Microsoft Authenticode documentation includes tutorials.
CAcert.org will sign a certificate you can use, and have instructions for getting started with Authenticode.
Sorry I can't be more helpful with VC, I don't use it, I usually using mingw and make, from some time ago targetting win32:
given a VERSIONINFO in a text version.rc file use mingw32-windres to compile it to a .o file (I actually had a bunch of .rc files, they were each #include-d in a single resources.rc so I only needed to run windres on that single file, and link a single extra object file)
include that version.o (or combined resources.o) in the final CC command, assuming compile and link to executable in one step
I also included -lversion when linking, AFAIR this was just because I used GetFileVersionInfo() for the code to check and display its own version in the 'About' dialog.
Make your program in a batch file, then using Advanced BAT to EXE Converter, convert it to EXE & fill out all of the fields. This sure helped me! :)
I am trying to build an old version of an application which consists of VC++ projects that were written in Visual Studio 2003.
My OS is Windows 7 Enterprise (64-bit).
When I try and build the solution I get the following errors:
error C4772: #import referenced a type from a missing type library; '__missing_type__' used as a placeholder
fatal error C1084: Cannot read type library file: 'Smegui.tlb': Error loading type library/DLL.
They both complain about the following import statement:
#import "Smegui.tlb" no_implementation
This is not a case of the file path being incorrect as renaming the Smegui.tlb file causes the compiler to throw another error saying it cannot find the library.
Smegui is from another application that this one depends on. I thought perhaps I was missing a dll but there is no such thing as Smegui.dll.
All I know about .tlb files is that they are a type library and you can create them from an assembly using tlbexp.exe or regasm.exe (the later also registers the assembly with COM)
There is also an Apache Ant build script which uses a custom task to invoke devenv.com to build the projects. This is the same script that the build server originally used to build the application. It gives me the same errors when I try and run it.
The strangest thing about this is that I knew it ought to work seeing as it is all freshly checked out from subversion. I tried many different combinations of admin vs user elevation, VS vs Ant build, cleaning, release.
I have got it to build successfully about 5 times but the build seems to be non-deterministic.
If anyone can shed some light on how this tlb stuff even works or what this error might mean I would greatly appreciate it.
I found a far more reliable solution: open the tlb with oleview.exe and then close it.
Not sure what this actually does but it works every time.
I think oleview is actually one of the samples included with Visual Studio but I haven't had the time to debug it and see what it is doing.
I ran into this error because one type library was trying to load a dependent type library, which it could not find. Even though the dependent type library was in the same directory, and even though that directory was in the searchable path, the compiler would error loading the first type library, but not mention the dependent type library in the error.
To find the pseudo-missing type library, I ran Process Monitor (procman64.exe) during the compile. This showed that after the reported type library had successfully loaded, a dependent type library could not be found. It even showed all of the places that it was looking for the dependent type library, none of which were where it should have been looking (e.g.: ).
The fix was to add a <PreBuildEvent> to the project to copy the dependent .tlb file to one of the directories that was actually being searched.
<PreBuildEvent>
<Command>copy /Y ..\Lib\Interop\CWSpeechRecLib.tlb .\</Command>
</PreBuildEvent>
http://msdn.microsoft.com/en-us/library/sce74ah7%28VS.71%29.aspx
smegui.tlb is referencing some other tlb that the compiler can't find. If you have the .idl for smegui you might be able to figure out what the other is. I suspect the missing tlb is something that original build machine had registered but that your machine doesn't have registered.
A type library is a binary description of a set of interfaces, coclasses and enums. They're usually generated for COM components, in the case of tlbexp and regasm the tlb is created from the assembly metadata. For native COM components they are usually generated from an idl (Interface Description Language) file by the midl tool.
Edit:
I just noticed you're on x64 Windows. Are you building the project with a new version of Visual Studio? If so, are you targeting x86 or x64? If the latter, it may simply be a 32bit component that the compiler can't find (or less likely, a x64 component the x86 compiler can't find if you are targeting x86), for WOW64 the registry is virtualized for x86 vs. x64 applications.
Well I finally found out why I managed to get it to build sometimes and not others... sort of.
So long as I ran the build script with elevated administrator permissions and let that get as far as it could until that error occurred, then run the build script again as a protected administrator succeeded. Those steps must be done in that exact order with no other steps in between. If I try build in Visual Studio it does not work (although I did get it to succeed once). Probably some kind of virtualisation issue although it still doesn't quite make sense.
Well I don't need help on this any more and I know it's probably impossible to fully answer this question without knowing exactly what the build is doing. However if anyone does have any more thoughts I would happily receive them.
Cheers,
Steiny