Problem with starting webcam

[Mustaphi]

Hello experts
I found this code that can launch the webcam and capture a picture.
It is working fine when I execute the code for the first time.
However to start the webcam again, I was obliged to restart windows.
This is the code:

Public Const WS_CHILD As Long = &H40000000
Public Const WS_VISIBLE As Long = &H10000000
Public Const WM_USER As Long = &H400
Public Const WM_CAP_START As Long = WM_USER
Public Const WM_CAP_DRIVER_CONNECT As Long = WM_CAP_START + 10
Public Const WM_CAP_DRIVER_DISCONNECT As Long = WM_CAP_START + 11
Public Const WM_CAP_SET_PREVIEW As Long = WM_CAP_START + 50
Public Const WM_CAP_SET_PREVIEWRATE As Long = WM_CAP_START + 52
Public Const WM_CAP_DLG_VIDEOFORMAT As Long = WM_CAP_START + 41
Public Const WM_CAP_FILE_SAVEDIB As Long = WM_CAP_START + 25

Public Declare Function capCreateCaptureWindow _
    Lib "avicap32.dll" Alias "capCreateCaptureWindowA" _
         (ByVal lpszWindowName As String, ByVal dwStyle As Long _
        , ByVal X As Long, ByVal Y As Long, ByVal nWidth As Long _
        , ByVal nHeight As Long, ByVal hwndParent As Long _
        , ByVal nID As Long) As Long

Public Declare Function SendMessage Lib "user32" _
    Alias "SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long _
        , ByVal wParam As Long, ByRef lParam As Any) As Long

Private Sub Cmd3_Click()
Dim temp As Long
temp = SendMessage(hCap, WM_CAP_DRIVER_DISCONNECT, 0&, 0&)
End Sub

Private Sub Cmd1_Click()
hCap = capCreateCaptureWindow("Take a Camera Shot", WS_CHILD Or WS_VISIBLE, 0, 0, PicWebCam.Width, PicWebCam.Height, PicWebCam.hWnd, 0)
    If hCap <> 0 Then
        Call SendMessage(hCap, WM_CAP_DRIVER_CONNECT, 0, 0)
        Call SendMessage(hCap, WM_CAP_SET_PREVIEWRATE, 66, 0&)
        Call SendMessage(hCap, WM_CAP_SET_PREVIEW, CLng(True), 0&)
    End If
End Sub

Private Sub Cmd2_Click()
Dim temp As Long
temp = SendMessage(hCap, WM_CAP_DLG_VIDEOFORMAT, 0&, 0&)
End Sub

This is what I get when I want to start the webcam for a second time



Thank you

[westconn1]

i have tested your code here it would restart the webcam OK, i have tried it on windows 10 and XP

just had to dimension hcap as module variable

[Mustaphi]

just had to dimension hcap as module variable

I did so but still sometimes it works and most of the time I have to restart windows.

[westconn1]

i tried it multiple times

you can download my sample from http://www.vbforums.com/showthread.p...ot-from-webcam
see if it works any better or not

did you try updating your webcam drivers?

[Mustaphi]

thanks sir for your interest
I tried your sample and it works fine for the first time but when I wanted to restart again I got the message No webcam found.
For updating the webcam drivers, I'll try that .

[Mustaphi]

I updated the driver but still the same problem.
thanks