How to write avi file from TBitmaps sequence?

Below is the key piece of code that you linked to, where IList

is this TStrings

with the names of all the files that should be included in the animation.

for i := 0 to IList.Count - 1 do begin
  AssignFile(BFile, IList[i]);
  Reset(BFile, 1);
  Seek(BFile, m_bfh.bfOffBits);
  BlockRead(BFile, m_MemBits[0], m_Bih.biSizeImage);
  Seek(BFile, SizeOf(m_Bfh));
  BlockRead(BFile, m_MemBitMapInfo[0], length(m_MemBitMapInfo));
  CloseFile(BFile);
  if AVIStreamWrite(psCompressed, i, 1, @m_MemBits[0],
      m_Bih.biSizeImage, AVIIF_KEYFRAME, 0, 0) <> 0 then begin
    ShowMessage('Error during Write AVI File');
    break;
  end;
end;

      

        
        
        
      

    

It reads chunks of a file from disk and writes them to an AVI stream. The important part is that it reads from files. The TBitmap

memory representation does not necessarily match the file representation. However, it is easy to adapt this code to temporarily store bitmaps in a memory stream; the stream will match the layout of the file. Suppose IList

now is an array TBitmap

as you suggested. Then we could use this:

var
  ms: TMemoryStream;

ms := TMemoryStream.Create;
try
  for i := 0 to Length(IList) - 1 do begin
    IList[i].SaveToStream(ms);
    ms.Position := m_bfh.bfOffBits;
    ms.ReadBuffer(m_MemBits[0], m_Bih.biSizeImage);
    ms.Position := SizeOf(m_Bfh);
    ms.ReadBuffer(m_MemBitMapInfo[0], Length(m_MemBitMapInfo));
    ms.Clear;
    if AVIStreamWrite(psCompressed, i, 1, @m_MemBits[0],
        m_Bih.biSizeImage, AVIIF_KEYFRAME, 0, 0) <> 0 then begin
      ShowMessage('Error during Write AVI File');
      break;
    end;
  end;
finally
  ms.Free;
end;

      

        
        
        
      

    

In the example above, the code that reads the first file in the list populates the various entries and sizes of the arrays used here, but you should be able to make the same changes there as I did with the code here.