TVideoCaptureDevice will not run in (Delphi 10.2.3)

[DavidJr. 1]

Hi,  I am following this example for setting up a VideoCaptureDevice app: https://docwiki.embarcadero.com/RADStudio/Sydney/en/Video_Capturing

 

I could not get the VideoCaptureDevice to start.  I tried 4 known good cameras and get the same thing,   I modified the code a bit to give me an indicator that I am indeed setting up the app right,  still nothing.  The app compiles just fine,  just won't start capture.

 

My version of Delphi is 10.2.3 and the following is my current code:

 

unit FMXCamera_Main;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.Objects,
  FMX.ListBox, FMX.Controls.Presentation, FMX.StdCtrls, FMX.Layouts, FMX.Media,
  FMX.Edit;

type
  TForm1 = class(TForm)
    Layout1: TLayout;
    btnStart: TButton;
    ComboBox1: TComboBox;
    Image1: TImage;
    procedure FormCreate(Sender: TObject);
    procedure ComboBox1Change(Sender: TObject);
    procedure btnStartClick(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    VideoCamera: TVideoCaptureDevice;

    procedure SampleBufferSync;
    procedure SampleBufferReady(Sender: TObject; const ATime: TMediaTime);
  end;

var
  Form1: TForm1;

implementation

// Delphi version of the implementation


{$R *.fmx}

procedure TForm1.btnStartClick(Sender: TObject);
begin
  if(VideoCamera <> nil) then
    begin
      if(VideoCamera.State = TCaptureDeviceState.Stopped) then
        begin
          VideoCamera.OnSampleBufferReady := SampleBufferReady;
          VideoCamera.CaptureSettingPriority := TVideoCaptureSettingPriority.FrameRate;
          VideoCamera.StartCapture;
          if(VideoCamera.State = TCaptureDeviceState.Capturing) then
            begin
              btnStart.Text := 'Stop';
            end
          else
            begin
              VideoCamera.StopCapture;
              btnStart.Text := 'Start';
            end;
        end
      else
        begin
          VideoCamera.StopCapture;
          btnStart.Text := 'Start';
        end;
    end
  else
    begin
      Caption := 'Video capture devices not available.';
    end;

end;

procedure TForm1.ComboBox1Change(Sender: TObject);
begin
  VideoCamera := TVideoCaptureDevice(TCaptureDeviceManager.Current.GetDevicesByName(ComboBox1.Selected.Text));

  if (VideoCamera <> nil) then
    begin
      btnstart.Text := 'Start '+VideoCamera.Name;
      btnStart.Enabled := true;
    end;
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  DeviceList: TCaptureDeviceList;
  i: integer;

begin
  DeviceList := TCaptureDeviceManager.Current.GetDevicesByMediaType(TMediaType.Video);
  for i := 0 to DeviceList.Count - 1 do
    begin
      ComboBox1.Items.Add(DeviceList[i].Name);
    end;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  if(VideoCamera <> nil) then
    begin
      VideoCamera.StopCapture;
    end;
end;

procedure TForm1.SampleBufferReady(Sender: TObject; const ATime: TMediaTime);
begin
  TThread.Synchronize(TThread.CurrentThread, SampleBufferSync);
  //Resize the image so that the video is buffered in its original size
  Image1.Width := Image1.Bitmap.Width;
  Image1.Height := Image1.Bitmap.Height;
end;

procedure TForm1.SampleBufferSync;
begin
  VideoCamera.SampleBufferToBitmap(Image1.Bitmap, true);
end;

end.

 

[programmerdelphi2k 235]

nevermind, sorry!

Edited February 14, 2023 by programmerdelphi2k

[Lars Fosdal 1732]

You have not identified the type of device, so I assume Android and/or iOS.
Has the app requested the right to use the camera?

Has approval been given?

Ref: https://docwiki.embarcadero.com/RADStudio/Tokyo/en/Uses_Permissions#camera

[DavidJr. 1]

6 hours ago, Lars Fosdal said:

You have not identified the type of device, so I assume Android and/or iOS.
Has the app requested the right to use the camera?

Has approval been given?

Ref: https://docwiki.embarcadero.com/RADStudio/Tokyo/en/Uses_Permissions#camera

Sorry  just my luck I'd leave out some information.

 

 

This is a Windows 10 OS, NOT Android.

[Lars Fosdal 1732]

Ah, in that case - ensure there is no other software that might grab the camera instead of your app?

[DavidJr. 1]

1 minute ago, Lars Fosdal said:

Ah, in that case - ensure there is no other software that might grab the camera instead of your app?

I have absolutely done all of that.  I am not even getting any errors in the IDE.

[Lars Fosdal 1732]

And there is nothing in the code that eats exceptions instead of exposing them?

What about stills? Can you get the example to work?

[DavidJr. 1]

1 minute ago, Lars Fosdal said:

And there is nothing in the code that eats exceptions instead of exposing them?

What about stills? Can you get the example to work?

The example did not work,  The Camera is in a state of "Stopped" after calling "StartCapture"

[Lars Fosdal 1732]

What about the Windows permissions?
https://support.microsoft.com/en-us/topic/87ebc757-1f87-7bbf-84b5-0686afb6ca6b

[DavidJr. 1]

1 hour ago, Lars Fosdal said:

What about the Windows permissions?
https://support.microsoft.com/en-us/topic/87ebc757-1f87-7bbf-84b5-0686afb6ca6b

I have done everything.  The camera permissions is open.    In VCL I am using other libraries that work just fine.  Its the FMX app that doesn't work.

[Lars Fosdal 1732]

I spotted this. Not sure if relevant?
https://stackoverflow.com/questions/45502430/how-to-access-camera-on-a-windows-tablet-with-firemonkey

[DavidJr. 1]

I have abandoned the FMX option.   Thanks.