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TagsReader.MP4_PictureFrameMemoryFileGet method |
  
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TagsReader.MP4_PictureFrameMemoryFileGet method |
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Remarks
Obtains a copy in memory of the picture file stored inside a MP4 picture frame.
For further details about methods related to tags reading refer to the TagsReader object.
For details about the reading of tags see the How to read TAG information in sound files tutorial.
Syntax
[Visual Basic] control.TagsReader.MP4_PictureFrameMemoryFileGet ( nIndex as Integer, pBuffer as variant, nBufferLen as long ) as enumErrorCodes |
[C++] short control.TagsReader.MP4_PictureFrameMemoryFileGet ( short nIndex, const VARIANT FAR& pBuffer, long nBufferLen ); |
Parameter |
Description |
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nIndex |
Zero-based index of the picture frame. The total number of picture frames available inside the MP4 tag can be obtained through a call to the TagsReader.MP4_PictureFrameCountGet method. |
pBuffer |
Output buffer that, on return from the method call, will contain the picture file data |
nBufferLength |
Length of the buffer expressed in bytes |
Return value
Value |
Meaning |
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Negative value |
An error occurred (see the LastError property for further error details) |
enumErrorCodes.NOERROR (0) |
The method call was successful. |
Below you can find a couple of samples that demonstrate how to retrieve a picture and store it inside a memory buffer in Visual Basic 6 and Visual C++ 6:
Visual Basic 6
Private Sub Command1_Click()
' obtain the size in bytes of the first available picture (having index 0)
Dim nSizeInBytes As Long
ActiveSoundEditor1.TagsReader.MP4_PictureFrameSizeGet 0, nSizeInBytes
if nSizeInBytes = 0 then Exit Sub
' allocate the destination buffer
Dim bytImage() As Byte
ReDim bytImage(nSizeInBytes)
' read picture data into the buffer
ActiveSoundEditor1.TagsReader.MP4_PictureFrameMemoryFileGet 0, VarPtr(bytImage(0)), nSizeInBytes
...
use the buffer
...
' erase the buffer and free memory
Erase bytImage
End Sub
Visual C++ 6 with MFC
void CReadId3v2Dlg::OnButton1()
{
long nSizeInBytes = 0;
m_editor.TagsReader.MP4_PictureFrameSizeGet (0, &nSizeInBytes);
if (nSizeInBytes == 0)
return;
BYTE *pBuffer = new BYTE[nTagSize];
COleVariant var;
var.vt = VT_BYREF | VT_UI1;
var.pbVal = pTagBuffer;
m_editor.TagsReader.MP4_PictureFrameMemoryFileGet (0, var, nSizeInBytes);
...
use the buffer
...
delete pBuffer;
}
