How to extract image from a AVI file?

[abhijit123]

I have developed an application to play a AVI file. I wish to have a image (possibly .gif or .jpeg) generated for a particular AVI frame. How do I achieve this?

Thanks in Advance!

 

[vb5prgrmr]

what methods/language are you using to play these AVI's? I Ask this because I have seen some examples at a couple of sites that do what you are looking todo in VB. Search

http://www.planet-source-code.com

or look in groups at google or yahoo to find sites that you can search.

Good Luck

 

[abhijit123]

I am using mcisendstring function to display AVI file in a frame.

 

[vb5prgrmr]

I don't remember (it been awhile) but if you are using VB check out the MMC (MultiMedia Control) you will be able to play an AVI frame by frame with that (check out the frames property).

Good Luck

 

[abhijit123]

I am able to display AVI file frame by frame. But I wish to capture a particular frame in an image.

For example if AVI file has 'n' frames, we should be able to get a image displaying contents of 'x' frame. The 'x' value will be a input field.

 

[vb5prgrmr]

Aahh! then I think you will need to do a screen capture. There are many examples on the web for that. Search this site for it or maybe

http://www.planet-source-code.com

or maybe check out the groups at Google or yahoo.

Good Luck

 

[abhijit123]

Hmm Screen Capture does not suit . Because it gives all the contents that are present on the screen. The image should have only contents from AVI frame.

your earlier reply helped me to get codes for screen capture from

http://www.planet-source-code.com

. However, I am still searching for appropriate sample code.

Thanks!

 

[vb5prgrmr]

Credit source site for code below:

http://allapi.mentalis.org/tips/capture.shtml

Ok this says it can capture any window as long as it has the handle to the window. So maybe you could make the form have only the AVI frame displayed...
[tt]
Option Explicit
Option Base 0

' This module contains several routines for capturing windows into a
' picture. All the routines work on both 16 and 32 bit Windows
' platforms.
' The routines also have palette support.
'
' CreateBitmapPicture - Creates a picture object from a bitmap and
' palette.
' CaptureWindow - Captures any window given a window handle.
' CaptureActiveWindow - Captures the active window on the desktop.
' CaptureForm - Captures the entire form.
' CaptureClient - Captures the client area of a form.
' CaptureScreen - Captures the entire screen.
' PrintPictureToFitPage - prints any picture as big as possible on
' the page.
'
' NOTES
' - No error trapping is included in these routines.

Private Type PALETTEENTRY
peRed As Byte
peGreen As Byte
peBlue As Byte
peFlags As Byte
End Type

Private Type LOGPALETTE
palVersion As Integer
palNumEntries As Integer
palPalEntry(255) As PALETTEENTRY ' Enough for 256 colors.
End Type

Private Type GUID
Data1 As Long
Data2 As Integer
Data3 As Integer
Data4(7) As Byte
End Type

Private Const RASTERCAPS As Long = 38
Private Const RC_PALETTE As Long = &H100
Private Const SIZEPALETTE As Long = 104

Private Type RECT
Left As Long
Top As Long
Right As Long
Bottom As Long
End Type

Private Declare Function CreateCompatibleDC Lib "GDI32" (ByVal hDC As Long) As Long
Private Declare Function CreateCompatibleBitmap Lib "GDI32" (ByVal hDC As Long, ByVal nWidth As Long, ByVal nHeight As Long) As Long
Private Declare Function GetDeviceCaps Lib "GDI32" (ByVal hDC As Long, ByVal iCapabilitiy As Long) As Long
Private Declare Function GetSystemPaletteEntries Lib "GDI32" (ByVal hDC As Long, ByVal wStartIndex As Long, ByVal wNumEntries As Long, lpPaletteEntries As PALETTEENTRY) As Long
Private Declare Function CreatePalette Lib "GDI32" (lpLogPalette As LOGPALETTE) As Long
Private Declare Function SelectObject Lib "GDI32" (ByVal hDC As Long, ByVal hObject As Long) As Long
Private Declare Function BitBlt Lib "GDI32" (ByVal hDCDest As Long, ByVal XDest As Long, ByVal YDest As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal hDCSrc As Long, ByVal XSrc As Long, ByVal YSrc As Long, ByVal dwRop As Long) As Long
Private Declare Function DeleteDC Lib "GDI32" (ByVal hDC As Long) As Long
Private Declare Function GetForegroundWindow Lib "USER32" () As Long
Private Declare Function SelectPalette Lib "GDI32" (ByVal hDC As Long, ByVal hPalette As Long, ByVal bForceBackground As Long) As Long
Private Declare Function RealizePalette Lib "GDI32" (ByVal hDC As Long) As Long
Private Declare Function GetWindowDC Lib "USER32" (ByVal hWnd As Long) As Long
Private Declare Function GetDC Lib "USER32" (ByVal hWnd As Long) As Long
Private Declare Function GetWindowRect Lib "USER32" (ByVal hWnd As Long, lpRect As RECT) As Long
Private Declare Function ReleaseDC Lib "USER32" (ByVal hWnd As Long, ByVal hDC As Long) As Long
Private Declare Function GetDesktopWindow Lib "USER32" () As Long

Private Type PicBmp
Size As Long
Type As Long
hBmp As Long
hPal As Long
Reserved As Long
End Type

Private Declare Function OleCreatePictureIndirect Lib "olepro32.dll" (PicDesc As PicBmp, RefIID As GUID, ByVal fPictureOwnsHandle As Long, IPic As IPicture) As Long

'''''''''''''''''''''''''''''''''''
' CreateBitmapPicture
' - Creates a bitmap type Picture object from a bitmap and
' palette.
'
' hBmp
' - Handle to a bitmap.
'
' hPal
' - Handle to a Palette.
' - Can be null if the bitmap doesn't use a palette.
'
' Returns
' - Returns a Picture object containing the bitmap.
'''''''''''''''''''''''''''''''''''
Public Function CreateBitmapPicture(ByVal hBmp As Long, ByVal hPal As Long) As Picture

Dim r As Long

Dim Pic As PicBmp
' IPicture requires a reference to "Standard OLE Types."
Dim IPic As IPicture
Dim IID_IDispatch As GUID

' Fill in with IDispatch Interface ID.
With IID_IDispatch
.Data1 = &H20400
.Data4(0) = &HC0
.Data4(7) = &H46
End With

' Fill Pic with necessary parts.
With Pic
.Size = Len(Pic) ' Length of structure.
.Type = vbPicTypeBitmap ' Type of Picture (bitmap).
.hBmp = hBmp ' Handle to bitmap.
.hPal = hPal ' Handle to palette (may be null).
End With

' Create Picture object.
r = OleCreatePictureIndirect(Pic, IID_IDispatch, 1, IPic)

' Return the new Picture object.
Set CreateBitmapPicture = IPic
End Function

'''''''''''''''''''''''''''''''''''
' CaptureWindow
' - Captures any portion of a window.
'
' hWndSrc
' - Handle to the window to be captured.
'
' Client
' - If True CaptureWindow captures from the client area of the
' window.
' - If False CaptureWindow captures from the entire window.
'
' LeftSrc, TopSrc, WidthSrc, HeightSrc
' - Specify the portion of the window to capture.
' - Dimensions need to be specified in pixels.
'
' Returns
' - Returns a Picture object containing a bitmap of the specified
' portion of the window that was captured.
'''''''''''''''''''''''''''''''''''
Public Function CaptureWindow(ByVal hWndSrc As Long, ByVal Client As Boolean, ByVal LeftSrc As Long, ByVal TopSrc As Long, ByVal WidthSrc As Long, ByVal HeightSrc As Long) As Picture

Dim hDCMemory As Long
Dim hBmp As Long
Dim hBmpPrev As Long
Dim r As Long
Dim hDCSrc As Long
Dim hPal As Long
Dim hPalPrev As Long
Dim RasterCapsScrn As Long
Dim HasPaletteScrn As Long
Dim PaletteSizeScrn As Long

Dim LogPal As LOGPALETTE

' Depending on the value of Client get the proper device context.
If Client Then
hDCSrc = GetDC(hWndSrc) ' Get device context for client area.
Else
hDCSrc = GetWindowDC(hWndSrc) ' Get device context for entire window.
End If

' Create a memory device context for the copy process.
hDCMemory = CreateCompatibleDC(hDCSrc)
' Create a bitmap and place it in the memory DC.
hBmp = CreateCompatibleBitmap(hDCSrc, WidthSrc, HeightSrc)
hBmpPrev = SelectObject(hDCMemory, hBmp)

' Get screen properties.
RasterCapsScrn = GetDeviceCaps(hDCSrc, RASTERCAPS) 'Raster capabilities.
HasPaletteScrn = RasterCapsScrn And RC_PALETTE 'Palette support.
PaletteSizeScrn = GetDeviceCaps(hDCSrc, SIZEPALETTE) 'Size of palette.

' If the screen has a palette make a copy and realize it.
If HasPaletteScrn And (PaletteSizeScrn = 256) Then
' Create a copy of the system palette.
LogPal.palVersion = &H300
LogPal.palNumEntries = 256
r = GetSystemPaletteEntries(hDCSrc, 0, 256, _
LogPal.palPalEntry(0))
hPal = CreatePalette(LogPal)
' Select the new palette into the memory DC and realize it.
hPalPrev = SelectPalette(hDCMemory, hPal, 0)
r = RealizePalette(hDCMemory)
End If

' Copy the on-screen image into the memory DC.
r = BitBlt(hDCMemory, 0, 0, WidthSrc, HeightSrc, hDCSrc, _
LeftSrc, TopSrc, vbSrcCopy)

' Remove the new copy of the on-screen image.
hBmp = SelectObject(hDCMemory, hBmpPrev)

' If the screen has a palette get back the palette that was
' selected in previously.
If HasPaletteScrn And (PaletteSizeScrn = 256) Then hPal = SelectPalette(hDCMemory, hPalPrev, 0)

' Release the device context resources back to the system.
r = DeleteDC(hDCMemory)
r = ReleaseDC(hWndSrc, hDCSrc)

' Call CreateBitmapPicture to create a picture object from the
' bitmap and palette handles. Then return the resulting picture
' object.
Set CaptureWindow = CreateBitmapPicture(hBmp, hPal)
End Function

'''''''''''''''''''''''''''''''''''
'
' CaptureScreen
' - Captures the entire screen.
'
' Returns
' - Returns a Picture object containing a bitmap of the screen.
'''''''''''''''''''''''''''''''''''
'
Public Function CaptureScreen() As Picture
Dim hWndScreen As Long

' Get a handle to the desktop window.
hWndScreen = GetDesktopWindow()

' Call CaptureWindow to capture the entire desktop give the handle
' and return the resulting Picture object.

Set CaptureScreen = CaptureWindow(hWndScreen, False, 0, 0, Screen.Width \ Screen.TwipsPerPixelX, Screen.Height \ Screen.TwipsPerPixelY)

End Function

'''''''''''''''''''''''''''''''''''
' CaptureForm
' - Captures an entire form including title bar and border.
'
' frmSrc
' - The Form object to capture.
'
' Returns
' - Returns a Picture object containing a bitmap of the entire
' form.
'''''''''''''''''''''''''''''''''''
Public Function CaptureForm(frmSrc As Form) As Picture
' Call CaptureWindow to capture the entire form given its window
' handle and then return the resulting Picture object.
Set CaptureForm = CaptureWindow(frmSrc.hWnd, False, 0, 0, frmSrc.ScaleX(frmSrc.Width, vbTwips, vbPixels), frmSrc.ScaleY(frmSrc.Height, vbTwips, vbPixels))
End Function

'''''''''''''''''''''''''''''''''''
' CaptureClient
' - Captures the client area of a form.
'
' frmSrc
' - The Form object to capture.
'
' Returns
' - Returns a Picture object containing a bitmap of the form's
' client area.
'''''''''''''''''''''''''''''''''''
'
Public Function CaptureClient(frmSrc As Form) As Picture
' Call CaptureWindow to capture the client area of the form given
' its window handle and return the resulting Picture object.
Set CaptureClient = CaptureWindow(frmSrc.hWnd, True, 0, 0, frmSrc.ScaleX(frmSrc.ScaleWidth, frmSrc.ScaleMode, vbPixels), frmSrc.ScaleY(frmSrc.ScaleHeight, frmSrc.ScaleMode, vbPixels))
End Function

'''''''''''''''''''''''''''''''''''
' CaptureActiveWindow
' - Captures the currently active window on the screen.
'
' Returns
' - Returns a Picture object containing a bitmap of the active
' window.
'''''''''''''''''''''''''''''''''''
Public Function CaptureActiveWindow() As Picture
Dim hWndActive As Long
Dim r As Long

Dim RectActive As RECT

' Get a handle to the active/foreground window.
hWndActive = GetForegroundWindow()

' Get the dimensions of the window.
r = GetWindowRect(hWndActive, RectActive)

' Call CaptureWindow to capture the active window given its
' handle and return the Resulting Picture object.
Set CaptureActiveWindow = CaptureWindow(hWndActive, False, 0, 0, RectActive.Right - RectActive.Left, RectActive.Bottom - RectActive.Top)
End Function

'''''''''''''''''''''''''''''''''''
' PrintPictureToFitPage
' - Prints a Picture object as big as possible.
'
' Prn
' - Destination Printer object.
'
' Pic
' - Source Picture object.
'''''''''''''''''''''''''''''''''''
'
Public Sub PrintPictureToFitPage(Prn As Printer, Pic As Picture)
Const vbHiMetric As Integer = 8
Dim PicRatio As Double
Dim PrnWidth As Double
Dim PrnHeight As Double
Dim PrnRatio As Double
Dim PrnPicWidth As Double
Dim PrnPicHeight As Double

' Determine if picture should be printed in landscape or portrait
' and set the orientation.
If Pic.Height >= Pic.Width Then
Prn.Orientation = vbPRORPortrait ' Taller than wide.
Else
Prn.Orientation = vbPRORLandscape ' Wider than tall.
End If

' Calculate device independent Width-to-Height ratio for picture.
PicRatio = Pic.Width / Pic.Height

' Calculate the dimentions of the printable area in HiMetric.
PrnWidth = Prn.ScaleX(Prn.ScaleWidth, Prn.ScaleMode, vbHiMetric)
PrnHeight = Prn.ScaleY(Prn.ScaleHeight, Prn.ScaleMode, vbHiMetric)
' Calculate device independent Width to Height ratio for printer.
PrnRatio = PrnWidth / PrnHeight

' Scale the output to the printable area.
If PicRatio >= PrnRatio Then
' Scale picture to fit full width of printable area.
PrnPicWidth = Prn.ScaleX(PrnWidth, vbHiMetric, Prn.ScaleMode)
PrnPicHeight = Prn.ScaleY(PrnWidth / PicRatio, vbHiMetric, Prn.ScaleMode)
Else
' Scale picture to fit full height of printable area.
PrnPicHeight = Prn.ScaleY(PrnHeight, vbHiMetric, Prn.ScaleMode)
PrnPicWidth = Prn.ScaleX(PrnHeight * PicRatio, vbHiMetric, Prn.ScaleMode)
End If

' Print the picture using the PaintPicture method.
Prn.PaintPicture Pic, 0, 0, PrnPicWidth, PrnPicHeight
End Sub

[/tt]

I have not tested it but I think you may be able to use it or something like it.

Good Luck

 

[abhijit123]

Thanks a lot!
I will check it out.

 

[abhijit123]

I was able to capture a bitmap of required size and required portion successfully.

Once again, thanks a lot!