video and picture boxes...

I need help in VB6 !

I have a MCI Multimedia Control and I want to play and process some video in a pictureBox (from different source: Avi files or video hardware).
I have a dll for image processing which need to copy the picture into the memory (for processing). It requires a Device Context and the hWnd property of the pictureBox:

Code:

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ImageToMemory Picture1.hDC, Picture1.hWnd, Width, Height

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The hWnd property doesn't seem to be important. So I don't know how to have the device context for a video stream that I could use with this function.

Moreover, user can move and resize a region of interest on the pictureBox with the mouse.

So, in a first time, I used two pictureBoxes, one was invisible and contained the original picture and the second picture used for display. When this picture was repaint I used paintpicture method and this worked fine.

Now, I want to process some video with the MMcontrol, so I had to change the paintpicture method into BitBlt.

For simple image I create a DC with CreatCompatibleDC and I use SelectObject to affect the bitmap I want.

But for video I can't find a DC of the MMcontrol except if I set MMcontrol.hWndDisplay to Picture1.hWnd and Picture1 is visible.

If Picture1 if partially hidden or not visible the bitblt function copy that is over the picture... and that very evil...


Do you understand my problem ?

well with the problem that it only copies the stuff partially or what's on top of it, you just need to set the autoredraw property of the source to TRUE
I don't really get your other questions... about that HWND for example. can you explain?

I've already put the autoredraw property to true but there is nothing in the device context of the hidden picture pox...

I'd like to do this:
In a image recognition application the user can load a bitmap or an avi video or a video capture hardware to learn or recognize patterns.
This image or video is displayed in a picture box and over it I draw two rectangles representing the region of scanning and the region of interrest for learning.
An other device is needed because those rectangles obstruct the image and I need a device context for calling image processing function.

What I've done for images works:

Loading...

Code:

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    Img = False 'false:video, true:image
    CommonDialog1.DialogTitle = "Chargement d'un média"
    CommonDialog1.FileName = ""
    CommonDialog1.Filter = "Image (*.bmp;*.jpg;*.gif)|*.bmp;*.jpg;*.gif|MetaFile (*.emf;*.wmf)|*.emf;*.wmf|Video (*.avi)|*.avi"
    CommonDialog1.ShowOpen
    imgStr = CommonDialog1.FileName
    tmpStr = Space(256)
    imgStr = left(tmpStr, GetShortPathName(imgStr, tmpStr, 256))
    If imgStr <> "" Then
        If mmDC <> 0 Then
            DeleteDC mmDC 'deleting the old dc
            mmDC = 0
        End If
        Picture1.Cls 'the user view
        If CommonDialog1.FilterIndex < 3 Then
            'picture
            Dim DBitmap As Bitmap
            mmDC = CreateCompatibleDC(0)
            If mmDC <> 0 Then
                Picture2.Picture = LoadPicture(imgStr)
                Img = True
                SelectObject mmDC, Picture2.Picture
                GetObject Picture2.Picture, Len(DBitmap), DBitmap
                H = DBitmap.bmHeight
                W = DBitmap.bmWidth

                'loading image for processing
                ImageToMemory mmDC, PictureImg.picture, W, H
            Else
                MsgBox "Error creating multimedia device context", _
                        vbOKOnly Or vbExclamation, "Loading"
            End If
        Else
            'video
                MMControl1.Command = "close"
                MMControl1.DeviceType = "avivideo"
                MMControl1.hWndDisplay = PictureImg.hWnd
                MMControl1.FileName = imgStr
                MMControl1.Command = "open"
                MMControl1.Command = "back"
                mmDC = PictureImg.hdc
        End If
    End If

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I add the code in a timer when this is a video:

Code:

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ImageToMemory mmDC, PictureImg.picture, W, H

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This function is used for image processing

displaying

Code:

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    BitBlt Picture1.hdc, 0, 0, W, H, _
      mmDC, ScaleX(HScroll1.Value, 1, 3), _
      ScaleY(VScroll1.Value, 1, 3), &HCC0020 'srccpy
    If CheckROS.Value Then
        Picture1.Line (RosCoord(0) - ScaleX(HScroll1.Value, 1, 3), _
          RosCoord(1) - ScaleY(VScroll1.Value, 1, 3))- _
          (RosCoord(2) - ScaleX(HScroll1.Value, 1, 3), _
          RosCoord(3) - ScaleY(FVScroll(6).Value, 1, 3)), _
          RosColor, B
    End If
    If CheckROI.Value Then
        Picture1.Line (RoiCoord(0) - ScaleX(HScroll1.Value, 1, 3), _
          RoiCoord(1) - ScaleY(VScroll1.Value, 1, 3))- _
          (RoiCoord(2) - ScaleX(HScroll1.Value, 1, 3), _
          RoiCoord(3) - ScaleY(VScroll1.Value, 1, 3)), _
          RoiColor, B
    End If

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This isn't working fine when I try to load a video...