Pure C# Silverlight video encoding lib? - c#

Is out there any Pure C# Silverlight video encoding lib?
By video I mean not only pictures compressor but also audio compressor...
So to say I'm looking for some kind of lib not only for compressing but also for sinchronisation etc... so to say I give it a web cam it gives me a conteiner!)

You're certainly not going to want to do this in safe code, unless you've got a lot of buffer memory, as the encoder would run glacially slowly.
One option is to run with elevated permissions, and then you can interact with external COM packages - see http://forums.silverlight.net/forums/p/156112/350144.aspx for some useful links
Here's a link from stackoverflow on the general issue that says pretty much the same thing - Using Native dlls in C# Com wrapper and Use dll in silverlight
If you can create a C# wrapper around calls to any native encoding DLL of your choice, then you can put the wrapper assembly in the GAC and you should be good to go - this would of course mean you need an additional install step to get this assembly into the gac, which is outside the 'normal' silverlight experience
To make this separation easier to implement and use, we introduced what we call the simple sandboxing APIs in the .NET Framework 2.0, which create each application domain with a given permission set for its sandbox and a list of fully trusted assemblies that are not in the Global Assembly Cache (GAC), as all assemblies in the GAC are already fully trusted.
taken from http://msdn.microsoft.com/en-us/magazine/cc765416.aspx - dated, but I believe still accurate

As of February 15, 2010 -- it appears that there is not a built-in way to do this in Silverlight.
Here is a thread that discusses this issue.
Rene Schulte has an example, EdgeCam Shots - Saving Silverlight 4 Webcam Snapshots to JPEG that saves the Webcam stream as sequential JPEG images.

Related

Is there a good way of extracting data from GUI on Windows OS using python libraries?

I'm currently working on a project which requires me to extract data from GUI on Windows OS - say I need to extract content such as the URL in my browser or the name of the attachment on Gmail.
I have already tried LDTP/Cobra, however it's pretty slow - each request can take up to 5 seconds and I need this library to be reasonably fast. Besides that, the LDTP/Cobra is pretty outdated and the latest MSI file doesn't work with python 3.* unless you modify the library itself.
I've been also researching the pywin API, however, it seems that you can't really extract anything with FindWindowEx and WM_GETTEXT method anymore, but I might be wrong.
My question is - is there any other library that would allow me to extract basically anything from a given Window? Maybe I'm missing an important part of the mentioned libraries? Ideally, I'm looking for a python library, but if there is no other way I could try and write some C# code.

Using Visualization Toolkit with IronPython

In my application, I have provision to run Python scripts through IronPython. In one of the requirement, the data from my C# application should be displayed in 3D using Visualization Toolkit. When I try to use VTK in a script and execute it, I get "ImportError: No module named vtk" error. I have searched for file named vtkCommonPython.pyd but cannot find it on my computer. Should Python be installed even after installing IronPython? What is the correct way to use VTK from IronPython?
In most cases, IronPython does not work with native/CPython modules like what vtkCommonPython.pyd seems to be. You will probably want to look at .NET bindings for VTK in order to use it from your IronPython scripts.
ActiViz.NET might be what you should be using. Wiki/Documentation, Download
Other modules containing only pure python should typically work fine. It's 'just' the native extensions that do not work as there is no easy (and built-in) way to make native code callable from .NET/IronPython using the same conventions as in CPython.
For additional info see the FAQ ('Compatibility') and the issue tracker.
You might also want to keep an eye on the recent effort to revive and port ironclad to IronPython 2.7. This project aims to provide the marshalling layer required to invoke CPython modules.

Creating .Net Wrappers for Windows API and COM DLLs

Let me start by saying that I don't know what I don't know at this point, so rather than specific answers, I'm also looking for better questions to ask, I think. My .Net/C# is solid enough, and my C/C++ is meh.
Lately, I'm finding that there are no libraries in the standard .Net framework to accomplish certain tasks, and while it's easy enough to download a third party library, I'd like to understand how to do it myself if one doesn't already exist.
In one recent case, I need to deal with MIDI in windows at a relatively low-level, and I accidentally found out that "winmm.dll" is the library I'll need to use by downloading a .net wrapper for MIDI and browsing through the source. I understand that I'll have to make a wrapper class and do the whole P/Invoke thing to make that happen.
The next thing I did was to search for documentation on the Windows API to figure out what was going on in the mystery box of "winmm.dll," and to my delight, there was a whole Windows SDK that I was able to download and read through. I went through the "getting started" section of "Windows Development" which covered some of the basics via C++. It talked a bit about COM, windows header files, and I know enough C++ to get the gist.
Now, I need help connecting the dots on a few issues:
1) The Windows SDK, so far, seems to suggest that I want to program to specific header files rather than the dlls themselves, but the .net wrappers I've found typically point to a specific .dll rather that a header file...
/// <summary>
/// Returns the number of MIDI input devices on this system.
/// </summary>
/// Win32 docs: http://msdn.microsoft.com/en-us/library/ms711608(VS.85).aspx
[DllImport("winmm.dll", SetLastError = true)]
public static extern UInt32 midiInGetNumDevs();
I was under the impression that a header file and DLL needed to be in the same folder, but the windows SDK includes a folder with all the windows header files, and no DLLs (I'm guessing the registry comes into play here for mapping to specific libraries?)? How do those header files eventually get mapped to actual libraries, and why does it seem like I don't even need to deal with header files to create a .Net wrapper?
2) I can't seem to find documentation on winmm.dll, but I have found references to the functions I'll likely need in the "Windows API" list in the Windows SDK, and I'm pretty sure that the code for those functions are in winmm.dll. How do I find the documentation for the specific libraries I'll need to begin creating my wrapper? If I didn't know that I was going to need winmm.dll to access windows MIDI functionality, how could I have figured that out myself?
3) Some DLLs are COM, some are plain windows DLLs, some are .net DLLs... how can I tell the different going forward? It seems that creating wrappers for the former two would require a different approach.
4) There is no page on MSDN for "Winmm.dll" listing all of its API, and I assume there's a good and practical reason for that, but I'm not sure what it is? I'm used to .Net land where I can figure out what a library does and how to use it almost without effort.
Thanks in advance for any insights.
The bible on this is Adam Nathans excellent book '.Net and COM the complete interoperability guide'
Includes PInvoke and several audio-type examples
1) The windows API documentation includes the header, library, and dll file for each method/enum/etc. I just didn't scroll down far enough when I read through to notice this. A header file doesn't necessarily have to be in the same directory as the dll; its contents are simply copy/pasted into the .c file when the program is compiled. The part I was missing here was the linking stage of compilation which I read about here
2) The documentation was there--I just had to look for it a little bit harder.
3) How can I detect the type of a dll? (COM, .NET, WIN32)
4) The api for audio could theoretically span multiple dlls, so the best course of action is to find the API documentation, find the methods you want to wrap, then figure out what dlls those methods are in, and then import each of those DLLs.

Using Mapnik in .net environment

Has anybody used Mapnik for rendering Maps from .net c# environment? I would like to use it to render maps in a desktop application developed under .net4. I found it the best open source map renderer tool, much more better, than the well known sharpmap, dotspatial (...). The 'only' problem is that it was written in C++ and Python and does not have a trivial way to use it from C#.
Do you know any .net Mapnik wrappers? Do you know any sample code?
I've just published my attempts in C# bindings.
They are available at: http://sourceforge.net/projects/mapniknet/
Some good new about Mapnik-.Net integration:
"Another thing that will help Windows developers is a way to use Mapnik from .Net languages. Although a full .Net wrapper is too much work besides all the other issues, hopefully I can make a meaningful start and open the door for .Net developers to leverage Mapnik in their applications."
Source: Mapnik homepage http://mapnik.org/news/2011/jun/09/gsoc_2011_windows_build_system_introduction/
NET-Mapnik
You might want to give this a try. Its pretty recent and has a simple example with options to create vector tiles.
https://github.com/kernelsanders/NET-Mapnik
So, finally I hacked it. Not a nice solution, but it works at least. In nutshell it operates in the following way:
developed a python script, which takes parameters as command line arguments. (using python api of mapnik)
call this python script by shell fom c# code (Process)
after map image has been generated, I show it in SharpMap as a background layer
In case of any map refresh (zoom, pan) I regenerate 'mapnik map layer'. I have also some kind of cache, in which I can store generated maps, so I can make tricks by using earlier generated map images or pre-generate them (e.g. generate maps for the next zoom level when user uses zoom tool). I also use some asynchron calls to do this, so I can create 1-3 map images paralelly.
The weak part of this solution is the communication between python and c# modules. I could not find better than command line arguments + shell.
My solution works, mapnik is fast, can genarate my maps less than a sec.
If you have any advice on .net - python communication (NO ironpython, it is not suitable for manik api), pls write it here. Thx.
Do you know about TAO Project?
It is a .Net project that takes unmanaged opengle library to .Net Managed Form by calling DllIMport() in C#.
You must do it for Mapnik, simaliar to TAOFramework.net

Working way to make video from images in C#

Does anybody have a known reliable way to create a video from a series of image files? Before you mod me down for not searching for the answer before posting the question, and before you fire off a simple message like "use FFMPEG," read the rest of this message.
I'm trying to create a video, it doesn't matter too much what format as long as it's widely supported, from a series of images (.jpg, .bmp, etc.). My platform is Windows Server 2008, 64-bit. If I can make the video from within my C# program, that's great, but I'm not averse to writing a series of image files to a directory and then firing off an external program to make a video from those images.
The only constraints are: it must work on my Windows Server 2008 system, and be scriptable. That is, no GUI programs that require operator intervention.
I found a number of similar questions on StackOverflow, and have tried several of the solutions, all with varying degrees of frustration and none with anything like success.
FFMPEG looks like a great program. Maybe it is, on Linux. The two Windows builds I downloaded are broken. Given this command line:
ffmpeg -r 1 -f image2 -i jpeg\*.jpg video.avi
One of the builds reads the images and then crashes due to data execution prevention. The other reads the first file and then spits out an error message that says "cannot find suitable codec for file jpeg/image2.jpg". Helpful, that. In any case, FFMPEG looks like a non-starter under Windows.
One answer to a previous posting recommended Splicer . It looks like pretty good code. I compiled the samples and tried to run, but got some cryptic error message about a file not found. It looks like a COM class isn't registered. I suppose I need to install something (DirectShow, maybe, although I thought that was already installed?). Depending on what's required, I might have a difficult time justifying its installation on a server. ("What? Why do you need that on a server?")
Another answer suggested the AviFile library from Code Project. That looks simple enough: a wrapper around the Windows AviFile subsystem. Except that the AVI files the package creates appear to have all of the frames, but only the first frame shows when I play the AVI in Windows Media Player. Well, that and if you try to create a compressed video, the program throws an exception.
So, I'm left wondering if there is a good, reliable way to do what I want: on a Windows system, create an AVI or other common video file format from a series of images, either through a .NET API or using an external program. Any help?
After working with it a while and taking a look at x264 and VideoLan, I went back to Splicer. It turns out that the cryptic error message was due to an error in my code.
It looks like Splicer will do what I want: programmatically create videos from a series of images.
Thanks to all who responded.
You can use VideoLan and I'd recommend it.
I've had direct experience in a C# application with VideoLan doing these two things:
Embedding a VLC viewer in my C# application (there are 3-4 C# "wrappers" for the VLC veiwer).
Using vlc.exe in a separate Process by sending it command-line arguments.
The fact that VideoLan has a command-line interface is a great thing. And VLC supports a command-line option that disables any visual element; so the VLC GUI doesn't pop up and neither does a command-line window. Thus, in a C# application you can farm out the video-related work to the VLC client. C# has the Process class which can manage your vlc.exe instances for you. It ends up being a pretty neat solution.
The handling of video on Windows (encoding and playback) is a real quagmire. And .NET isn't going to help you at all - you're always going to be either PInvoking/COM-interoping native APIs or using a .NET wrapper that someone else has built to do the same.
Anyway, I can't say I've used it, but a good bet seems to be the x264 library that is part of the videolan project. That gives you a self-contained C library that you can PInvoke and you don't have to worry about installing and DirectShow garbage on your server. It'll generate H.264 format video which is playable in Flash as I understand it.
I've used mplayer's mencoder to create AVI (with codecs msmpeg4/mp3, readable by default with Windows Media Player) from TGA files on linux like this:
mencoder mf://*.tga -mf fps=25:type=tga \
-audiofile /tmp/test.mp3 -oac copy \
-of lavf -ovc lavc \
-lavcopts vcodec=msmpeg4v2:mbd=2:mv0:trell:cbp:last_pred=3:vbitrate=3000 \
-o /tmp/test.avi
I know mplayer does have a Windows version.
Instead of just going through all the hassle, you could coppy all the images that you want to be included in your video to the clipboard and have it imported into Windows Live Movie Maker (dynamically, of course!) and have it compile for you!
All of this CAN be done through code, but this way, you don't have to create it yourself. As you said that the platform was Windows, and ALL Windows comps have Windows Live Movie Maker installed, so it shouldn't be a problem for anyone using your application unless
a) They uninstalled Windows Live Movie Maker
b) They are using a computer running on a Windows Version more than 8 or 9 years old...

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