VFW | Varnish Firewall - | Caching library

I am developing an C++ application which should use an USB camera to capture high resolution photos. It should have same behavior as the Camera application in Windows 10. I am trying to use DirectShow for doing it. Now I am only able to take high resolution photo which is delayed or take a photo in time but low resolution. Also I am very confused from MS documentation, lot of things are deprecated and nowhere mentioned what replaces them. I'll describe my hopeless steps awaiting there will be somebody who could be able to show me a way.

Let's start from beginning...

Knowing nothing about video capturing in Window I started by searching suitable library. After some googling I found there are four main libraries for capturing video in Windows.

1. Video for Windows
2. DirectShow
3. Windows Media Foundation
4. OpenCV

Let's observe:

1. Video for Windows
   This library is unfortunately marked as deprecated but it seems it still works. I have written "unfortunately", because I think this is the only which is easy to use. There are only a few lines of code needed for seeing video from camera. The only think I miss here is a "TakePhoto" function. You can use VFW for capture a video or single frames to an avi file. Or am I missing something?

2. DirectShow
   This is much more complicated library. You need hundreds of lines of code to see a video preview. But you can obtain this code on MS Docs. Ok, now I have a video preview and I need only to take a photo. One would expect this should be just one function call. But where is the function? I did not find it.

You can simply use GetCurrentImage from IVMRWindowlessControl but this takes only one frame from preview with low resolution. If you set a higher resolution for preview the video is not fluent.

Best approach I could achieve is from an article called "Capturing an Image From a Still Image Pin" available here https://docs.microsoft.com/en-us/windows/desktop/directshow/capturing-an-image-from-a-still-image-pin. When I had found this site I thought I won and my task was almost finished. But it wasn't.

The first advice which the article gives you is not to use it: "The recommended way to get still images from the device is to use the Windows Image Acquisition (WIA) APIs. For more information, see "Windows Image Acquisition" in the Platform SDK documentation. However, you can also use DirectShow to capture an image." I tried to explore the WIA. But this stopped to work on Vista. I continued to study the article.
Everything seems to be clear but you need to implement your class which inherits ISampleGrabberCB marked as deprecated here https://docs.microsoft.com/en-us/windows/desktop/directshow/isamplegrabbercb. Why???? Where to find some alternative?
I found an acceptable solution here https://social.msdn.microsoft.com/Forums/windowsdesktop/en-US/2ab5c212-5824-419d-b5d9-7f5db82f57cd/qedith-missing-in-current-windows-sdk-v70?forum=windowsdirectshowdevelopment. You need to add header file from elder SDK. (BTW This is an advice almost ten years old.) After I compiled the application with this header I was able to read high resolution picture but I need to wait a few seconds which is unacceptable. I know the problem is not in camera, because in the it works in the Camera application. Furthermore the image is obtained in function SampleCB instead of BufferCB and is in some strange format. I can save it as jpg but it is not compressed enough.

1. Windows Media Foundation
   I think MS doesn't like programmers and that's why it released WMF. I understand nothing. I found this tutorial https://www.dreamincode.net/forums/topic/347938-a-new-webcam-api-tutorial-in-c-for-windows/. It works but it only stores one frame from preview and this is not what I want.
   Next I explored some WMF interfaces on MS Docs. IMFCapturePhotoSink interface should do the stuff. But how implement it. The documentation is useless.

2. OpenCV
   During my research I found also this library. But again I'm not able to take a high resolution photo. It only stores one frame from preview.

Could someone tell me what should I focus on? I believe it cannot be so difficult. There are tens and hundreds of applications for webcams. How could other programmers implement them? What's wrong with me? I'd like to find an easy way to implement an easy task. Thank a lot for any help.

I would like to record screen video then save as Mp4,Webm or any video format. I am using SharpAvi to record video,The code below is recording video but I am unable to save after stop ,Please help Here is my code.

I'm trying to wrap a little handy piece of C++ code that is intended to generate video+audio on windows using VFW, the C++ library lives here and the descriptions says:

Uses Video for Windows (so it's not portable). Handy if you want to quickly record a video somewhere and don't feel like wading through the VfW docs yourself.

I'd like to use that C++ library on Python so I've decided to wrap it up using swig.

Thing is, I'm having some problems when it comes to encode the audio, for some reason I'm trying to understand why the generated video is broken, it seems the audio has not been written properly in the video file. That means, if I try to open the video with VLC or any similar video player I'll get a message saying the video player can't identify the audio or video codec. The video images are fine so it's definitely a problem with the way I'm writing the audio to the file.

I'm attaching both the swig interface and a little Python test that's trying to be a port of the original c++ test.

aviwriter.i

I am doing a windows based app where I use a camera. I want to allow the user to change camera settings (VfwCaptureDialog_Source) as it is common in skype or amcap application. For now, I found out that the dialog is from vfw and it can be activated from dshow api. When I do it from AmCap, it is working. Can you help me to get this code working for given webcam (multiple camera support is required)? I use Qt and OpenCV while working with camera. In opencv just camera index is used to select proper camera. The index is from Qt where can I get nice list of camera names. The error I get from this code is 1170 : "The property set specified does not exist on the object"

Morning all,

Does anyone on here have experience with using AForge and Video or webcam apps?

There is a .cs file called VideoCaptureDeviceForm that is part of AForge.DirectShow which provides a way of selecting a local video device i.e webcam.

I want to be able to automatically detect and start the webcam on my computer but a dialogbox pops up asking to select a webcam. I need a way to either bypass this in someway or automatically press the OK button.

Dialogbox

I have tried using SendKeys.Send("{ENTER}") within the open dialogbox button method i.e Start camera but I get errors.

Within VideoCaptureDeviceForm.cs, there is a method called okButton_Click and the next idea is to manipulate this to do what I want the app to do.

Unfortunately I don't have the experience to figure this out. Can anyone advise on how to do this or what I should do next? Thank you.

VideoCaptureDeviceForm.cs is below:

Good afternoon,

The vfw framework has an option to add a text stream to a video. Is this stream supposed to show up as a subtitle stream in the final video file? I use the ‘AVIStreamWrite’ function to write text to each frame.

My question, is the text stream supposed for subtitle use? Is there perhaps an alternative to write/draw/bake subtitles into frames using the vfw framework?

I've got the feeling 'video for windows' is getting quite old and no longer supported/maintained. Perhaps there is a newer tool set?

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There is not much theory or documentation on the concepts of streams and samples in Video For Windows API (VFW). I am wondering if a video should only contain:

• one video stream
• one audio stream

Or can a video contain multiple video streams (one after the other) and multiple audio streams?

I assume a "sample" just means one frame of the video, not multiple frames. I assume a stream, is a collection of frames or collection of samples. So it would be useful to divide a video into multiple streams (collections of frames) to make multiple "sections", or multiple streams

If you cannot have multiple streams in a video, and this api is only designed to have one video stream per video (with an optional audio stream), how would one create a video composed of multiple sections? Just edit/cut/paste directly into a single stream? Or use a different API such as MediaFoundation/DirectShow instead?