DSPackを使用してウェブカメラからスナップショットを撮ってJPEGに保存するには？

Question

DSPackを使って、Delphi XEウェブカメラからスナップショットを撮り、その前にユーザーがJPEGファイルに保存することを許可する必要があります。これはどうすればできますか（コード）？

Answer 1

これはうまくいくかもしれませんが、私はそれをテストしていません。あなたはそれを試してみるべきです。

unit main; 

interface 

uses 
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
Dialogs, StdCtrls, DSPack, DSUtil, DirectShow9; 

type 
TMainForm = class(TForm) 
    CaptureGraph: TFilterGraph; 
    VideoWindow: TVideoWindow; 
    ListBox1: TListBox; 
    VideoSourceFilter: TFilter; 
    StartButton: TButton; 
    StopButton: TButton; 
    Label1: TLabel; 
    ListBox2: TListBox; 
    Label3: TLabel; 
    procedure FormCreate(Sender: TObject); 
    procedure FormDestroy(Sender: TObject); 
    procedure ListBox1Click(Sender: TObject); 
    procedure StartButtonClick(Sender: TObject); 
    procedure StopButtonClick(Sender: TObject); 
private 
    { Private declarations } 
public 
    { Public declarations } 
end; 

var 
MainForm: TMainForm; 
VideoDevice: TSysDevEnum; 
VideoMediaTypes: TEnumMediaType; 
implementation 

{$R *.dfm} 

{ TMainForm } 

procedure TMainForm.FormCreate(Sender: TObject); 
var i: integer; 
begin 
VideoDevice := TSysDevEnum.Create(CLSID_VideoInputDeviceCategory); 
for i := 0 to VideoDevice.CountFilters - 1 do 
    ListBox1.Items.Add(VideoDevice.Filters[i].FriendlyName); 

VideoMediaTypes := TEnumMediaType.Create; 
end; 

procedure TMainForm.FormDestroy(Sender: TObject); 
begin 
VideoDevice.Free; 
VideoMediaTypes.Free; 
end; 

// Selecting of the video source 
procedure TMainForm.ListBox1Click(Sender: TObject); 
var 
PinList: TPinList; 
i: integer; 
begin 
VideoDevice.SelectGUIDCategory(CLSID_VideoInputDeviceCategory); 
if ListBox1.ItemIndex <> -1 then 
begin 
    // Set the device which we work with 
    VideoSourceFilter.BaseFilter.Moniker := VideoDevice.GetMoniker(ListBox1.ItemIndex); 
    VideoSourceFilter.FilterGraph := CaptureGraph; 
    CaptureGraph.Active := true; 
    PinList := TPinList.Create(VideoSourceFilter as IBaseFilter); 
    ListBox2.Clear; 
    VideoMediaTypes.Assign(PinList.First); 
    // Adding permission to ListBox2, which supports device 
    for i := 0 to VideoMediaTypes.Count - 1 do 
    ListBox2.Items.Add(VideoMediaTypes.MediaDescription[i]); 
    CaptureGraph.Active := false; 
    PinList.Free; 
    StartButton.Enabled := true; 
end; 
end; 

procedure TMainForm.StartButtonClick(Sender: TObject); 
var 
PinList: TPinList; 
begin 

// Activating graph filter, at this stage the source filter is added to the graph 
CaptureGraph.Active := true; 

// The configuration of the output device 
if VideoSourceFilter.FilterGraph <> nil then 
begin 
    PinList := TPinList.Create(VideoSourceFilter as IBaseFilter); 
    if ListBox2.ItemIndex <> -1 then 
    with (PinList.First as IAMStreamConfig) do 
     SetFormat(VideoMediaTypes.Items[ListBox2.ItemIndex].AMMediaType^); 
    PinList.Free; 
end; 

// now render streams 
with CaptureGraph as IcaptureGraphBuilder2 do 
begin 
    // Hooking up a preview video (VideoWindow) 
    if VideoSourceFilter.BaseFilter.DataLength > 0 then 
    RenderStream(@PIN_CATEGORY_PREVIEW, nil, VideoSourceFilter as IBaseFilter, 
     nil , VideoWindow as IBaseFilter); 

end; 
// Launch video 
CaptureGraph.Play; 
StopButton.Enabled := true; 
StartButton.Enabled := false; 
ListBox2.Enabled := false; 
ListBox1.Enabled := false; 
end; 

// Stop video 
procedure TMainForm.StopButtonClick(Sender: TObject); 
begin 
StopButton.Enabled := false; 
StartButton.Enabled := true; 
CaptureGraph.Stop; 
CaptureGraph.Active := False; 
ListBox2.Enabled := true; 
ListBox1.Enabled := true; 
end; 

end.