I am interested in developing an application that will allow me to build a list of videos from xml (containing video title, duration, etc) and play that list as my webcam stream. Meaning, if I were to visit ustream.tv, or activate my webcam on live messenger my video playlist would register as my active webcam.
Does anybody have experience in this area, and perhaps have some advice to offer?
If you want this to work so that third party apps see your video as a standard webcam stream (and is sounds very much like you do) then the only way to do it is to write a virtual webcam driver. You will then then be able to "play" your video content as your webcam's streaming output. This will involve writing code to decode the video content - probably using DirectShow - and then copying the raw video stream to the webcam's output stream. You'll need to either write a custom DirectShow renderer filter or use the sample grabber to access the raw, decoded frames.
It's certainly an achievable goal, but not particularly easy given that both DirectShow and driver development have fairly steep learning curves. There are a variety of different driver models you could use for this, depending on exactly what your aims are. The easiest thing would be to create a Video for Windows (VfW) virtual camera driver. The huge benefit of this approach is that the driver will be entirely user mode code - much easier to debug and to write in general.
I don't have a lot of experience in this area, but I would start by looking at the MSDN docs for the DirectShow API.
A couple of .NET wrapper libraries exist as well:
Managed DirectShow
DirectShow.NET
Another DirectShow.NET
Related
I have created a project using directShow that takes the captured video from a webcam and preview it.
Now I want to encode on run time video captured alive and save it on desk then play it back I want to use it as part from my code(dll for example) not a standalone part.
Any links can help me to get how to do that please I am in search process for a week and feel not understood with the methodology?
If you're writting new app, or you're interested in learn about video processing you should consider using Microsoft Media Foundation.
DirectShow is an 'obsolete' and shortly will be discontinued technology.
If despite this, you're still interested in DirectShow, you could start with MSDN DirectShow Documentation (Examples are in C++ but the idea is the same).
As short summary you must understand this concepts.
What is a DirectShow Filter, and wich types exists (Source,Transform,Renderers and Capture).Introduction to DirectShow
How can I connect multiple Filters in a Graph,how filters are connected between them, and how I can control the playback. Start with Building the Filter Graph.
Some utils that can help you:
DirectShow Graph Spy DLL Allows to watch Graphs created by others app
Monogram Graph Studio Improved version of Microsoft Graph Edit.
NOTE: As you tagged this post with 'C#' and 'Directshow.NET' tags, I will consider that you're using DirectShow.NET library (the unofficial port of DirectShow to .NET).
I'm trying to find the way for getting image (only image, not video stream) from webcam in managed C#.
Usually people suggesting libraries, but they are old or commercial or under gpl.
How get image from webcam without third-party libraries?
upd.: thanks for Media Foundation, I shall use that.
Web cameras are supposed to deliver video feeds, not stills. So the native API you might be interested in is the one for video capture, which are DirectShow and Media Foundation.
The one you would most likely want is DirectShow, but it is not well suited to be interfaced from managed code, so you will need a DirectShow.NET which is open source wrapper. You typically start video streaming there and once you have a good image you stop the activity.
Or instead you might keep looking for a ready to use library which does the mentioned above for you.
One of DirectShow.NET samples does what you look for.
DxSnap – Use DirectShow to take snapshots from the Still pin of a
capture device. Note the MS encourages you to use WIA for this, but if
you want to do in with DirectShow and C#, here's how.
It mentions WIA, however WIA API is not available for all (or any in recent OSes?) web cameras, WIA more targets device like scanners.
Other APIs are perhaps less suitable.
VFW ("avicap32.dll") limits you to a subset of devices, is simple yet not well interfaced into managed code
Media Foundation is not well available in earlier OS versions
I wrote this many years ago
http://www.vbforums.com/showthread.php?344471-Vb.Net-WebCam-Class-(ICam)) in VB.net
You could easily port it to c#?
Is avicap32.dll out of the question?
Otherwise I think this is a simple and straightforward way:
http://www.creativecodedesign.com/node/66
http://www.c-sharpcorner.com/uploadfile/yougerthen/integrate-the-web-webcam-functionality-using-C-Sharp-net-and-com-part-viii/
I want to put a news marquee over an analog TV stream using c#, I can stream analog TV using DirectShow but I can't figure out how to mix it with rotating text, should I create a filter? or I have to use another technology than DirectShow?
DirectShow is the simplest way of doing this but it does have a bit of a learning curve, particularly coming from C#. The Wikipedia page gives you a basic overview of DirectShow.
DirectShow tools are available in the latest Windows SDK. Using C++ for DirectShow programming is more straightforward but you can use DirectShow fairly easily via COM interop or DirectShow.net (which I haven't tried yet). If using COM interop the following article is helpful:
http://blogs.msdn.com/b/ericgu/archive/2004/09/20/232027.aspx
You may be able to use the VMR overlay filter if the animation performance is smooth enough. See the following articles
http://www.codeproject.com/KB/audio-video/VideoPicture.aspx
http://www.codeproject.com/KB/audio-video/Ticker.aspx
http://msdn.microsoft.com/en-us/library/dd407344(v=vs.85).aspx
Alternatively you will need to write your own filter that renders the text on each frame adjusting its position in synch with the time stamps of the video frames. If you only need to do this inside your own application then the following approach might be easiest
http://www.sichbo.ca/Free_Code/100_C_Sharp_directshow_filters
Microsoft officially recommend that DirectShow filters should be created in C++ for performance reasons but overlaying scrolling text should be OK in C# as the bottleneck will be the APIs used to overlay the text if you program carefully.
Actually you don't have to write a filter to draw some text over your video. Just make a graph where uncompressed video goes through sample grabber (one of standard DirectShow filters), set up a callback for the sample grabber and you'll be able to modify the video data in your callback. Doing it in C# is very easy using DirectShow.NET but not optimal due to marshalling. You can first build such a graph in GraphEditPlus, then it will show you source code in C# or C++ of how to build this graph and use sample grabber.
Do we have a way to simulate a webcam driver, that will provide realtime captured screen (30 frames per sec) as it's output?
This is one of several features of ManyCam (free). It is a virtual webcam driver through which you can stream your real webcam video (with optional real-time video effects), video or image files, or your full/partial desktop.
Yes, just google video2webcam. It works quite well and will loop a video or picture as output.
The driver's job is to provide a level of abstraction between the software and hardware. The driver is supposed to issue commands to the hardware. It's not responsible for taking pictures and turning it into an animated GIF for instance. It's going to do low level stuff like, turn the device on and off, send raw data to a socket.
That being said, if you need to create a virtual device driver. Here's an overview of VDD's. Windows Programming/Device Driver Introduction
Generally these are not written in higher-level languages such as C#. Rather, they are written in languages such as C/C++. You will need the KMDF, or Kernel-Mode Driver Framework.
If you just need to access a webcam from a .NET application on a system with a webcam, you just need an API.
Open your browser.. go to google.com and type ".NET webcam API"
You will see something like this:
Webcam in your own application
It appears that this is a wrapper for the DirectShow class.
I am looking to put a camera on top of a my lab in the process of being built and stream it to a website.
How can I be doing this with only c# ? How to get stream of video & send it live on server PC from there he can take instant photos?
Modern web cameras would supports WIA and DirectShow. WIA has a scripting interface which is more friendly to C#, however it is designed for cameras and scanners and is not that fast for streaming. But if you just need to push the image to a server, you don't need to write code, kist use Windows Media Encoder to push to a Windows Media Server's publishing point. You can then get image from the server's publishing point using DirectShow or Windows Media Format SDK. None of these are easy in C# though, you are better off using COM class libraries like ATL for extensive COM programming like this.
If you really want to write this in C#, I've had a lot of success with Egmu.
Capturing images is very straightforward - see this question. After that, it'd be FTP to the server as usual.
I'm curious about Sheng Jiang's Media Encoder solution though. Let me know how you get on.