VB.Net Conversion of BMP to AVI

[FirebirdGuy]

Keywords: VB.Net, AVI Compression, avifil32.dll

Hello, I have been struggling for days now to write a VB.Net application which converts BMP Images to AVI. This program works just fine in VB but will not run in VB.Net. The problem lies with the conversion of VarPtr() in VB to some other means in VB.Net.

The main problem begins when calling the avifil32.dll function AVISaveOptions Defined as follow:

Public Declare Function AVISaveOptions Lib "avifil32.dll" (ByVal hWnd As Integer, ByVal uiFlags As Integer, ByVal nStreams As Integer, ByRef ppavi As Integer, ByRef ppOptions As Integer) As Integer TRUE if user pressed OK, False if cancel, or error if error

This function wants to receive a pointer to a pointer to an AVI_COMPRESS_OPTIONS Structure. The problem is that with VB.Net we are working with managed memory and it seems this function wants a pointer to a pointer to unmanaged memory.

It has been suggested to use the following algorithm in order to get the VarPtr within .Net:

Public Function VarPtr(ByVal o As Object) As Integer
    Dim oGC As GCHandle = GCHandle.Alloc(o, GCHandleType.Pinned)
    Dim ret As Integer = oGC.AddrOfPinnedObject.ToInt32
    oGC.Free()
    Return ret
End Function

I have attempted to use this method with no luck at all... I then came across another trick for allocating the memory of the AVI_COMPRESS_OPTIONS to unmanaged memory, and then passing a pointer to that memory location to the AVISaveOptions function. Once the function has completed I then read the memory location back in and I can get the updated valued from the AVISaveOptions call. Here is the code that accomplishes this for me:

Dim opts As AVI_COMPRESS_OPTIONS
//Allocate enough memory on the global heap
Dim lpB As IntPtr = Marshal.AllocHGlobal(Len(opts))

Dim source(11) As Integer  11 elements in AVI_COMPRESS_OPTIONS, all of type Integer
Dim destination(11) As Integer
source(0) = opts.fccType
source(1) = opts.fccHandler
source(2) = opts.dwKeyFrameEvery
source(3) = opts.dwQuality
source(4) = opts.dwBytesPerSecond
source(5) = opts.dwFlags
source(6) = opts.lpFormat
source(7) = opts.cbFormat
source(8) = opts.lpParms
source(9) = opts.cbParms
source(10) = opts.dwInterleaveEvery

//Copy the managed array to the un-managed pointer
Marshal.Copy(source, 0, lpB, 11) Len(opts))

Dim pOpts As Integer
pOpts = lpB.ToInt32()

res = AVISaveOptions(Me.Handle.ToInt32, ICMF_CHOOSE_KEYFRAME Or ICMF_CHOOSE_DATARATE, 1, ps, pOpts) 

 Get the data back out of unmanaged memory
Marshal.Copy(lpB, destination, 0, 11)
opts.fccType = destination(0)
opts.fccHandler = destination(1)
opts.dwKeyFrameEvery = destination(2)
opts.dwQuality = destination(3)
opts.dwBytesPerSecond = destination(4)
opts.dwFlags = destination(5)
opts.lpFormat = destination(6)
opts.cbFormat = destination(7)
opts.lpParms = destination(8)
opts.cbParms = destination(9)
opts.dwInterleaveEvery = destination(10)

At this point my opts object has valid information after the user has chosen their AVI format to save as. Everything seems to be going ok at this point, the following code executes without error:

res = AVIMakeCompressedStream(psCompressed, ps, opts, 0)

I am still wondering if passing opts at this point is valid, have I updated the object properly to pass it into this function call?

Then, once I try to call AVIStreamSetFormat the application fails with a return HRESULT which has a value of -2147205018 (AVIERR_BADPARAM ). Here is how I call that function:

Dim B() As Byte = bmp.GetBitmapInfo()
Dim iLength As Integer = B.Length

//Allocate enough memory on the global heap
Dim lpB2 As IntPtr = Marshal.AllocHGlobal(iLength)

//Copy the managed array to the un-managed pointer
Marshal.Copy(B, 0, lpB2, iLength)

res = AVIStreamSetFormat(psCompressed, 0, lpB2.ToInt32(), iLength)

This code fails totally when selecting the MPEG4 compression format, it seems to succeed with some other formats but the file is never written to with my calls to AVIStreamWrite. It would seem that the problem lies somehow with the opts.lpParms value which is created by the AVI dll since the code passes the AVIStreamSetFormat when this value is set to 0, and not otherwise. Just for completeness, here is how I call the AVIStreamWrite method:

 Now write out each video frame
For i = 0 To listBoxImageList.Items.Count - 1
    listBoxImageList.SelectedIndex = i
bmp.CreateFromFile(listBoxImageList.Text) load the bitmap (ignore errors)
     bmp.PointerToBits uses the same technique as above with using the Marshal class to get a pointer the an unmanaged memory location holding the bitmap info.
    res = AVIStreamWrite(psCompressed, i, 1, bmp.PointerToBits, bmp.SizeImage, AVIIF_KEYFRAME, 0, 0)
    If (res <> AVIERR_OK) Then
        MsgBox("AVIStreamWrite failed.")
        Exit Function
    End If
Next

The Declared Functions are below:

Public Declare Function AVIMakeCompressedStream Lib "avifil32.dll" (ByRef ppsCompressed As Integer, ByVal psSource As Integer, ByRef lpOptions As AVI_COMPRESS_OPTIONS, ByVal pclsidHandler As Integer) As Integer 

Public Declare Function AVIStreamSetFormat Lib "avifil32.dll" (ByVal pavi As Integer, ByVal lPos As Integer, ByRef lpFormat As Integer, ByVal cbFormat As Integer) As Integer

Public Declare Function AVIStreamWrite Lib "avifil32.dll" (ByVal pavi As Integer, ByVal lStart As Integer, ByVal lSamples As Integer, ByVal lpBuffer As Integer, ByVal cbBuffer As Integer, ByVal dwFlags As Integer, ByRef plSampWritten As Integer, ByRef plBytesWritten As Integer) As Integer

Can anyone help me out and tell me what I am doing wrong in my code. Unfortunately I am not a strong C++ programmer and am weak when it comes to pointers. Has anyone had success with writing bmp images to an AVI file after choosing a compression type in .NET? Any help would be greatly appreciated.

 

[SteveD]

I was struggling with a similar problem in C# (the bmp-to-avi thing, not the rest of it). I have a friend who came up with a solution and is now making a go at wrapping up that entire API. I will post his C# code when I can get ahold of it - hopefully that will help.

 

[FirebirdGuy]

steved, that would be great, I need to see some working source code whether it be C# or VB.Net, either is good
Anyone else have any idea why the above code doesnt work or what I am doing wrong?

 

[SteveD]

Sorry it took so long. He wanted to add an example app before making it public. I havent looked at this version yet, but he tells me it still uses all P/Invokes of the vfw API stuff, there is no comments, and to give him credit for blah, blah...

Have fun with it. I think Gabe (the guy who wrote it) will be updating it as he makes improvements, so let me know if you have any trouble. Good luck!

http://midget3d.com/gabe/AviLib.zip

 

[FirebirdGuy]

Thanks steved, Ill take a look at it. Any code I borrow from there I have no problem whatsoever giving credit for Thank your friend as well for sharing some code on this difficult subject.

 

[FirebirdGuy]

steved/Gabe, thanks so much, Ive been playing around with the DLL/code and it works well. Ive been struggling for days to get cod that does what your DLL does. I see now how it is done but dont think I could have figured that out on my own. I should be ok from here out, thanks again.

 

[SteveD]

Hey, no prob! Im glad it helped. Ill be sure to let Gabe know his first-ever GPL code already helped someone.

 

[alx_dot_net]

Could someone post the classes in VB.NET format?

 

[Volte]

You can compile the library as a DLL and use it from VB.NET projects, regardless of what language it is orginally in.

 

[carlblanchard]

Nice work gabe

I have used this in a vb application and it works very nice

however compression dosnt seem to work ?

My File size is Huge

Let us know the score

Regards
Carl Blanchard

PS VB for kid

Dim aviObj As New AviLib.AviWriter("output.avi", AviLib.AviCompression.None, Convert.ToUInt32(24), 1280, 1024)
        Dim bitmaps As String() = Directory.GetFiles(System.Environment.CurrentDirectory & "\temp\", "*.jpg")
        Dim bitmap As String

        For Each bitmap In bitmaps
            Console.WriteLine(bitmap)
            aviObj.WriteFrame(New Bitmap(bitmap))
        Next bitmap

        aviObj.Close()
        GC.Collect()

 

[Giotto]

could you share the AviLib that I cant copile it?

Hi Carl
could you share the AviLib that I cant copile it?
Thanks AB

I have used this in a vb application and it works very nice

however compression dosnt seem to work ?

My File size is Huge

Let us know the score

Regards
Carl Blanchard

PS VB for kid

Dim aviObj As New AviLib.AviWriter("output.avi", AviLib.AviCompression.None, Convert.ToUInt32(24), 1280, 1024)
        Dim bitmaps As String() = Directory.GetFiles(System.Environment.CurrentDirectory & "\temp\", "*.jpg")
        Dim bitmap As String

        For Each bitmap In bitmaps
            Console.WriteLine(bitmap)
            aviObj.WriteFrame(New Bitmap(bitmap))
        Next bitmap

        aviObj.Close()
        GC.Collect()

 

[Giotto]

Can You help me?

Hi steved
Could you provide the dll since I would try to use it in VB.net and Ihavent C#compiler?
Thanks a lot
AB

Sorry it took so long. He wanted to add an example app before making it public. I havent looked at this version yet, but he tells me it still uses all P/Invokes of the vfw API stuff, there is no comments, and to give him credit for blah, blah...

Have fun with it. I think Gabe (the guy who wrote it) will be updating it as he makes improvements, so let me know if you have any trouble. Good luck!

http://midget3d.com/gabe/AviLib.zip

 

[lhk_mgtf2008]

Help on convert BMP to API

i need this file http://midget3d.com/gabe/AviLib.zip

izit possible i get the original source...

 

[dynamic_sysop]

if you look @ this example in C# ... link ...
you will see this structure ...

[StructLayout(LayoutKind.Sequential, Pack=1)]
	public struct AVICOMPRESSOPTIONS {
	public UInt32   fccType;
	public UInt32   fccHandler;
	public UInt32   dwKeyFrameEvery;
	public UInt32   dwQuality;
	public UInt32   dwBytesPerSecond;
	public UInt32   dwFlags;
	public IntPtr   lpFormat;
	public UInt32   cbFormat;
	public IntPtr   lpParms;
	public UInt32   cbParms;
	public UInt32   dwInterleaveEvery;
}

you should be creating a new instance of one of those, filling it with all the stuff you need and sending that as the last parameter of the AviSaveOptions call.

check out the link, its on the codeproject & although its in C# it is easy enough to understand from a vb point of view.