Styjun

I am setting up a software (SOFT1) that takes video frame grabs in JPG format and sent to another software (SOFT2) using Tidtrivialftp.

SOFT2 is to receive the Jpeg and display in a TImage for review.

I am not sure what I am doing wrong. The code is a cut and paste from another post on here. It seems to work but I get nothing in my TImage and if I try to save to disk I get a 0KB file.

I tried implementing the solution found on this link:

Udp image streaming, delphi indy10

Trying to send a small test.jpg which is only 2.48KB for testing purpose.

Client Side:

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:UsersEtienneDesktopMyVideoatest.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;

Server Side:

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:UsersEtienneDesktopPictest.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;

I am expecting the file I am sending (test.jpg) to appear in img1 and also be saved in 'C:UsersEtienneDesktopPictest.jpg'

The code does work in the way that it saved the file and assign it to img1 but its empty.

This is all done locally.

Its like "IdtrivialFTPClientFrameGrab.Put(Strmkoko, 'test.jpg');" is sending an empty file. But I have tried several ways to load the stream and always the same result.

I understand that TCP/IP would be better but I would like to get this to work. Any help would be appreciated.

Cheers,
E.

After a lot of trials I figured out the problem. I do not know why it was omitted from the examples shown in the other posts but after you received the Stream you have to reset its position before you can load it...

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:UsersEtienneDesktopPictest.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;