Sip from the Firehose

RAD Studio XE3 includes new classes for identifying, managing and using the audio and video capture devices that are available on your target Windows and Mac computers.  In a previous blog post I showed you how write code that captures audio in a FireMonkey 2 Windows and Mac application.  In this blog post I show you how to list all of the audio and video capture devices that are available on a computer (you can do this using Delphi and C++Builder).  On my Mac, this code will find several audio capture devices, and the built-in camera.  The following is the output from the program when running on a MacBook Pro:

Here is the Delphi code used to display the devices in the bitmap above on my MacBook Pro:

uses
  System.SysUtils, System.Types, System.UITypes, System.Rtti, System.Classes,
  System.Variants, FMX.Types, FMX.Controls, FMX.Forms, FMX.Dialogs, FMX.Layouts,
  FMX.Memo, FMX.Media;

type
  TForm3 = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    Label1: TLabel;
    Button2: TButton;
    Label2: TLabel;
    Memo2: TMemo;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
    NumberOfDevices : integer;
  public
    { Public declarations }
  end;

implementation
{$R *.fmx}
uses System.TypInfo;

procedure TForm3.Button1Click(Sender: TObject);
var
  i : integer;
begin
  // get the number of audio and video capture devices - if any
  NumberofDevices := TCaptureDeviceManager.Current.Count;
  Label1.Text := 'Devices: '+IntToStr(NumberOfDevices);
  Memo1.Lines.Clear;
  // for each capture device, display the index, name, media type and the state
  for i := 0 to NumberOfDevices-1 do begin
    Memo1.Lines.Add(
      IntToStr(i)
      + ': "'
      + TCaptureDeviceManager.Current.Devices[i].Name
      + '", Type: '
      + GetEnumName(System.TypeInfo(TMediaType),
            Ord(TCaptureDeviceManager.Current.Devices[i].MediaType))
      + ', State: '
      + GetEnumName(System.TypeInfo(TCaptureDeviceState),
           Ord(TCaptureDeviceManager.Current.Devices[i].State))
    );
  end;
end;

You can use TCaptureDeviceManager to provide user choices of the audio and video devices to use. On my Samsung Slate 7, running Windows 8 Professional, the code finds one audio capture device and two video cameras. I can use this information to provide a choice of which camera to use to grab video frames.

Have fun working with your audio and video capture devices using RAD Studio XE3 and FireMonkey 2.

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