Re: Displaying WMV from a stream with the WM ASF Reader Filter in a filter graph
From: Bob Dellaca (bobdlxyzzy_at_xtra.co.nz)
Date: 01/13/05
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Date: Fri, 14 Jan 2005 11:30:30 +1300
Here is the source code of a sample unit to play an OGG file from a
stream (here a TStream (TFileStream)).
It uses DS Pack 2.3.4 and the DS filters from oggDS0995.exe The filter
to handle the input stream is derived from the Async Filter Sample in
the DirectShow SDK (as translated in DS Pack). Setting
MEDIASUBTYPE_ogg should result in the filter graph manager rendering
source filter -> ogg splitter -> ogg decoder -> sound renderer
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls,
Forms,
Dialogs, Menus,
ActiveX, DirectShow9, BaseClass, UAsyncIO, UAsyncRdr;
type
TBCFileStream = class(TBCAsyncStream)
private
FLock: TBCCritSec;
FLength: LONGLONG;
FPosition: LONGLONG;
FStream: TStream;
public
constructor Create(Stream: TStream);
destructor Destroy; override;
function SetPointer(APos: LONGLONG): HResult; override;
function Read(ABuffer: PByte; ABytesToRead: DWord;
AAlign: Boolean; out ABytesRead: DWord):
HResult; override;
function Size(out ASizeAvailable: LONGLONG): LONGLONG; override;
function Alignment: DWord; override;
procedure Lock; override;
procedure Unlock; override;
end;
TBCFileReader = class(TBCAsyncReader)
public
function Register: HResult; override; stdcall;
function UnRegister: HResult; override; stdcall;
constructor Create(AStream: TBCFileStream; Amt: PAMMediaType;
out hr: HResult);
end;
TForm1 = class(TForm)
MainMenu1: TMainMenu;
File1: TMenuItem;
Openoggfile1: TMenuItem;
OpenDialog1: TOpenDialog;
Exit1: TMenuItem;
procedure Openoggfile1Click(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure Exit1Click(Sender: TObject);
private
Stream: TBCFileStream;
Reader: TBCFileReader;
pFilgraphManager: IMediaControl;
pGraph: IGraphBuilder;
pStream: TFileStream;
procedure CloseIt;
public
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
constructor TBCFileStream.Create(Stream: TStream);
begin
FStream := Stream;
FLength := FStream.Size;
FPosition := 0;
FLock := TBCCritSec.Create;
inherited Create;
end;
destructor TBCFileStream.Destroy;
begin
if Assigned(FLock) then
FreeAndNil(FLock);
inherited Destroy;
end;
function TBCFileStream.SetPointer(APos: LONGLONG): HResult;
begin
if (APos < 0) or (APos > FLength) then
Result := S_FALSE else
begin
FPosition := APos;
FStream.Position := APos;
Result := S_OK;
end;
end;
function TBCFileStream.Read(ABuffer: PByte; ABytesToRead: DWord;
AAlign: Boolean;
out ABytesRead: DWord): HResult;
var
ReadLength: DWord;
begin
FLock.Lock;
try
if (FPosition + ABytesToRead > FLength) then
ReadLength := FLength - FPosition else
ReadLength := ABytesToRead;
FStream.Read(ABuffer^, ReadLength);
Inc(FPosition, ReadLength);
ABytesRead := ReadLength;
Result := S_OK;
finally
FLock.UnLock;
end;
end;
function TBCFileStream.Size(out ASizeAvailable: LONGLONG): LONGLONG;
begin
ASizeAvailable := FLength;
Result := FLength;
end;
function TBCFileStream.Alignment: DWord;
begin
Result := 1;
end;
procedure TBCFileStream.Lock;
begin
FLock.Lock;
end;
procedure TBCFileStream.Unlock;
begin
FLock.UnLock;
end;
constructor TBCFileReader.Create(AStream: TBCFileStream;
Amt: PAMMediaType;
out hr: HResult);
begin
inherited Create('File reader', nil, AStream, hr);
CopyMemory(@Fmt, Amt, SizeOf(TAMMediaType));
end;
function TBCFileReader.Register: HResult;
begin
Result := S_OK;
end;
function TBCFileReader.UnRegister: HResult;
begin
Result := S_OK;
end;
procedure TForm1.Openoggfile1Click(Sender: TObject);
const
MEDIASUBTYPE_ogg: TGUID = '{D2855FA9-61A7-4DB0-B979-71F297C17A04}';
var
mt: TAMMediaType;
pmt: PAMMediaType;
hr: HResult;
Pin: IPin;
begin
if OpenDialog1.Execute then
begin
CloseIt;
CoCreateInstance(CLSID_FilterGraph, nil, CLSCTX_INPROC_SERVER,
IID_IFilterGraph2, pGraph);
pFilgraphManager := pGraph as IMediaControl;
pStream := TFileStream.Create(OpenDialog1.FileName, fmOpenRead);
try
Stream := TBCFileStream.Create(pStream);
pmt := @mt;
TBCMediaType(pmt).InitMediaType;
mt.majortype := MEDIATYPE_Stream;
mt.subtype := MEDIASUBTYPE_ogg;
Reader := TBCFileReader.Create(Stream, @mt, hr);
Reader._AddRef;
pGraph.AddFilter(Reader, nil);
Pin := Reader.GetPin(0);
pGraph.Render(Pin);
except
on E:Exception do
begin
MessageDlg(E.Message, mtError, [mbOk], 0);
pGraph := nil;
CloseIt;
Exit;
end;
end;
pFilgraphManager.Run;
end;
end;
procedure TForm1.CloseIt;
begin
if pGraph <> nil then
begin
pFilgraphManager.Stop;
pGraph := nil;
end;
pFilgraphManager := nil;
Reader := nil;
FreeAndNil(Stream);
FreeAndNil(pStream);
end;
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
CloseIt;
end;
procedure TForm1.Exit1Click(Sender: TObject);
begin
Close;
end;
end.
- Next message: Stefan Bellon: "Re: Looking for a hash table"
- Previous message: Bruce Roberts: "Re: Looking for a hash table"
- In reply to: Thaddy de Koning: "Re: Displaying WMV from a stream with the WM ASF Reader Filter in a filter graph"
- Next in thread: Bob Dellaca: "Re: Displaying WMV from a stream with the WM ASF Reader Filter in a filter graph"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
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