FILE: AVIRSCE.EXE Plays an AVI Stored in a Resource .dll File

ID: Q173668

The information in this article applies to:

Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, version 5.0

SUMMARY

This article shows you how to play an AVI file stored in a resource .dll file through Visual Basic. Although you can add an AVI file to a resource file in Visual Basic and then compile the Visual Basic project into a .dll file, the AVI file is accessible only through Visual Basic.

An AVI file stored in a resource .dll file compiled in Visual C++ has two advantages:

The file is accessible from more than one application written in several different programming languages, such as both Visual C and Visual Basic.

If you need to change the resource file because you need to change the AVI file, you only have to change one file. That file can reside on a server and become accessible to all programs using that file.

MORE INFORMATION

The following file is available for download from the Microsoft Software Library:

~ Avirsce.exe (25Kb)

For more information about downloading files from the Microsoft Software Library, please see the following article in the Microsoft Knowledge Base:

Q119591 : How to Obtain Microsoft Support Files from Online Services

When you run the self-extracting file Avirsce.exe, the following files are expanded into the directory, AVI Resource Sample Project, on your hard drive:


 - Avirsce.vbp (1Kb)-the project file
 - Avirsce.vbw (1Kb)-the workspace file
 - Form1.frm   (2Kb)-the form file
 - Module1.bas (5Kb)-the module file
 - Readme.txt       -you are reading this file

Steps to Create the Sample

This sample assumes you have a compiled resource .dll file with an AVI file. You also need the Resource.h file for the resource .dll file in order to determine the identifier for the AVI file.

Look for a line similar to this one in the Resource.h file to determine the AVI file identifier:


   #define IDR_AVI1     101

The identifier for the AVI file in this case is 101.

To create a resource .dll file containing an AVI file, please see the following article in the Microsoft Knowledge Base:

Q178199 : HOWTO: Create a Resource DLL File Containing an AVI

Start a new Standard EXE project. Form1 is created by default.

Add a CommandButton to Form1.

Copy the following code to the Code window of the Form1 form. (Add the AVI file identifier and the path to the resource .dll file in the lines marked with the comment <<<< ):


      Option Explicit
      Private Sub Command1_Click()
         Dim hRsrc As Long
         Dim hGlobal As Long
         Dim lpString As String
         Dim strCmd As String, strReturnVal As String
         Dim nbuf As Long

         'Identifier for the AVI in the resource file from the resource.h
         'file of the resource dll, which must be preceded by '#'.
         lpString = "#101" '                                       <<<<

         'Loads the resource
         'Change the filename argument in the next line to the path and
         'filename of your resource dll file.
         hInst = LoadLibrary("<Path resource dll file name>") '    <<<<
         hRsrc = FindResource(hInst, lpString, "AVI")
         hGlobal = LoadResource(hInst, hRsrc)
         lpData = LockResource(hGlobal)
         fileSize = SizeofResource(hInst, hRsrc)

         Call mmioInstallIOProc(MEY, AddressOf IOProc, _
                                MMIO_INSTALLPROC + MMIO_GLOBALPROC)
         nbuf = 256

         'Play the AVI file
         strCmd = "open test.MEY+ type avivideo alias test"
         strReturnVal = mciSendString(strCmd, 0&, 0&, 0&)
         strCmd = "play test wait"
         strReturnVal = mciSendString(strCmd, 0&, 0&, 0&)
         strCmd = "close test"
         strReturnVal = mciSendString(strCmd, 0&, 0&, 0&)

         Call mmioInstallIOProc(MEY, vbNull, MMIO_REMOVEPROC)
         FreeLibrary hInst
      End Sub

From the Project menu, click Add Module to create a new module.

Copy the following code to the code window of the Module1 module.


      Option Explicit
      Public lpData As Long
      Public fileSize As Long
      Public hInst As Long

      Public Const MMIO_INSTALLPROC = &H10000   'mmioInstallIOProc:install
                                                'MMIOProc

      Public Const MMIO_GLOBALPROC = &H10000000 'mmioInstallIOProc: install
                                                'globally

      Public Const MMIO_READ = &H0
      Public Const MMIOM_CLOSE = 4
      Public Const MMIOM_OPEN = 3
      Public Const MMIOM_READ = MMIO_READ
      Public Const MMIO_REMOVEPROC = &H20000
      Public Const MMIOM_SEEK = 2
      Public Const SEEK_CUR = 1
      Public Const SEEK_END = 2
      Public Const SEEK_SET = 0
      Public Const MEY = &H2059454D   'This is the value of "MEY " run
                                      'through FOURCC

      'Create a user defined variable for the API function calls
      Public Type MMIOINFO
         dwFlags As Long
         fccIOProc As Long
         pIOProc As Long
         wErrorRet As Long
         htask As Long
         cchBuffer As Long
         pchBuffer As String
         pchNext As String
         pchEndRead As String
         pchEndWrite As String
         lBufOffset As Long
         lDiskOffset As Long
         adwInfo(4) As Long
         dwReserved1 As Long
         dwReserved2 As Long
         hmmio As Long
      End Type

      'Finds the specified resource in an executable file. The function
      'returns a resource handle that can be used by other functions used
      'to load the resource.
      Public Declare Function FindResource Lib "kernel32" _
         Alias "FindResourceA" _
         (ByVal hInstance As Long, _
          ByVal lpName As String, _
          ByVal lpType As String) _
         As Long

      'Returns a global memory handle to a resource in the specified
      'module. The resource is only loaded after calling the LockResource
      'function to get a pointer to the resource data.
      Public Declare Function LoadResource Lib "kernel32" _
         (ByVal hInstance As Long, _
          ByVal hResInfo As Long) _
          As Long

      'Locks the specified resource. The function returns a 32-bit pointer
      'to the data for the resource.
      Public Declare Function LockResource Lib "kernel32" _
         (ByVal hResData As Long) As Long

      'Loads the specified dll file and maps the address space for the
      'current process.
      Public Declare Function LoadLibrary Lib "kernel32" _
         Alias "LoadLibraryA" (ByVal lpLibFileName As String) As Long

      'Frees the specified .dll file loaded with the LoadLibrary function.
      Public Declare Function FreeLibrary Lib "kernel32" _
         (ByVal hLibModule As Long) As Long

      'Copies a block of memory from one location to another.
      Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
         (hpvDest As Any, _
          hpvSource As Any, _
          ByVal cbCopy As Long)

      'Installs or removes a custom I/O procedure. This function also
      'locates an installed I/O procedure, using its corresponding
      'four-character code.
      Public Declare Function mmioInstallIOProc Lib "winmm" _
         Alias "mmioInstallIOProcA" _
         (ByVal fccIOProc As Long, _
          ByVal pIOProc As Long, _
          ByVal dwFlags As Long) _
          As Long

      'Sends the specified command string to an MCI device.
      Public Declare Function mciSendString Lib "winmm.dll" _
         Alias "mciSendStringA" _
         (ByVal lpstrCommand As String, _
          ByVal lpstrReturnString As Long, _
          ByVal uReturnLength As Long, _
          ByVal hwndCallback As Long) _
         As Long

      'Returns the size, in bytes, of the specified resource.
      Public Declare Function SizeofResource Lib "kernel32" _
         (ByVal hInstance As Long, _
          ByVal hResInfo As Long) As Long

      'Accesses a unique storage system, such as a database or file
      'archive. Install or remove this callback function with the
      'mmioInstallIOProc function.
      Public Function IOProc _
         (ByRef lpMMIOInfo As MMIOINFO, _
          ByVal uMessage As Long, _
          ByVal lParam1 As Long, _
          ByVal lParam2 As Long) _
          As Long

      Static alreadyOpened As Boolean

      Select Case uMessage
         Case MMIOM_OPEN
            If Not alreadyOpened Then
                alreadyOpened = True
                lpMMIOInfo.lDiskOffset = 0
            End If
            IOProc = 0

         Case MMIOM_CLOSE
            IOProc = 0

         Case MMIOM_READ:
            Call CopyMemory(ByVal lParam1, ByVal _
                            lpData + lpMMIOInfo.lDiskOffset, lParam2)
            lpMMIOInfo.lDiskOffset = lpMMIOInfo.lDiskOffset + lParam2
            IOProc = lParam2

         Case MMIOM_SEEK

         Select Case lParam2
            Case SEEK_SET
               lpMMIOInfo.lDiskOffset = lParam1

            Case SEEK_CUR
               lpMMIOInfo.lDiskOffset = lpMMIOInfo.lDiskOffset + lParam1
               lpMMIOInfo.lDiskOffset = fileSize - 1 - lParam1

            Case SEEK_END
               lpMMIOInfo.lDiskOffset = fileSize - 1 - lParam1
         End Select

         IOProc = lpMMIOInfo.lDiskOffset

         Case Else
            IOProc = -1 ' Unexpected msgs.  For instance, we do not
                        ' process MMIOM_WRITE in this sample
      End Select

      End Function ' IOProc

Press the F5 key to run the project. Click the command button to play the AVI file.

REFERENCES

For additional information, please see the following articles in the Microsoft Knowledge Base:

Q124947 : Retrieving Palette Information From a Bitmap Resource

Q155360 : How to use MCI to Play AVI/WAVE Files From Memory

Visual Basic 5.0 Programmer's Guide to the Win32 API by Dan Appleman, ZD Press

Platform SDK Reference Guide: Multimedia Functions


Keywords          : kbsample kbVBp500 kbhowto 
Version           : WINDOWS:5.0
Platform          : WINDOWS 
Issue type        : kbhowto

Last Reviewed: May 12, 1999