Question

我正在设置一个软件（SOFT1），该软件将JPG格式的视频帧抓取并使用Tidtrivialftp发送到另一个软件（SOFT2）。

SOFT2将接收Jpeg并显示在TImage中以供查看。

我不确定自己在做什么错。该代码是从此处另一篇文章中剪切并粘贴的。它似乎可以正常工作，但是我的TImage中什么也没有，如果尝试将其保存到磁盘，则会得到一个0KB的文件。

我尝试实施此链接上找到的解决方案：

尝试发送一个仅2.48KB的小test.jpg以供测试。

客户端：

procedure TForm1.BtnClick(Sender: TObject);
var
  Myjpg: TJPEGImage;
  Strmkoko : TMemoryStream;
begin

try
    //Tried a lot of different ways to load the jpg into a stream. This is the latest one with same results.

    Strmkoko := TMemoryStream.Create;
    Myjpg := TJPEGImage.Create;
    Myjpg.LoadFromFile('C:\Users\Etienne\Desktop\MyVideo\a\test.jpg');
    Myjpg.SaveToStream(Strmkoko);
    Strmkoko.Position := 0;
    Image1.Picture.assign(Myjpg); //Confirming MyJpg is showing the picture by placing it in a TImage component before sending - All ok

    //Also tried to just put the filename instead of stream. - no difference
    IdtrivialFTPClientFrameGrab.Put(Strmkoko, 'test.jpg');

finally
    Strmkoko.Free;
    Myjpg.Free;
end;
end;

服务器端：

procedure TForm2.IdFTPServerFrameGrabTransferComplete(Sender: TObject;
  const Success: Boolean; const PeerInfo: TPeerInfo; var AStream: TStream;
  const WriteOperation: Boolean);
var
jpg: TJPEGImage;
begin
  if WriteOperation and Success then
  begin
    jpg := TJPEGImage.Create;
    try
      jpg.LoadFromStream(AStream);
      jpg.SaveToFile('C:\Users\Etienne\Desktop\Pic\test.jpg'); //trying to save the jpg to check what I get and its 0KB
      img1.Picture.Assign(jpg); //This is the final place I want to send the stream
    finally
      jpg.Free;
    end;
  end;
end;

procedure TForm2.IdFTPServerFrameGrabWriteFile(Sender: TObject;
  var FileName: string; const PeerInfo: TPeerInfo; var GrantAccess: Boolean;
  var AStream: TStream; var FreeStreamOnComplete: Boolean);
begin
  if Filename = 'test.jpg' then
  begin
    //Code does get in here when I debug
    GrantAccess := True;
    AStream := TMemoryStream.Create;
    FreeStreamOnComplete := True;
  end else
    GrantAccess := False;
end;

我希望发送的文件（test.jpg）出现在img1中，并且也保存在'C：\ Users \ Etienne \ Desktop \ Pic \ test.jpg'

代码确实以保存文件并将其分配给img1的方式工作，但其为空。

这都是在本地完成的。

就像“ IdtrivialFTPClientFrameGrab.Put（Strmkoko，'test.jpg'）;“正在发送一个空文件。但是我尝试了几种方法来加载流并始终获得相同的结果。

我知道TCP / IP会更好，但是我想使它工作。任何帮助将不胜感激。

干杯， E。

Answer 1

经过大量试验，我发现了问题所在。我不知道为什么在其他文章中显示的示例中省略了它，但是在收到Stream之后，必须重置其位置才能加载它...

AStream.Position：= 0;

procedure TForm2.IdFTPServerFrameGrabTransferComplete(Sender: TObject;
  const Success: Boolean; const PeerInfo: TPeerInfo; var AStream: TStream;
  const WriteOperation: Boolean);
var
jpg: TJPEGImage;
begin
  if WriteOperation and Success then
  begin
    jpg := TJPEGImage.Create;
    try
      AStream.Position := 0; // <----- insert here
      jpg.LoadFromStream(AStream);
      jpg.SaveToFile('C:\Users\Etienne\Desktop\Pic\test.jpg'); //trying to save the jpg to check what I get and its 0KB
      img1.Picture.Assign(jpg); //This is the final place I want to send the stream
    finally
      jpg.Free;
    end;
  end;
end;

无法通过Tidtrivialftp发送JPG。收到的文件为0KB

1 个答案: