【例子介绍】用DirectShow 的方式，视频输入设备枚举、视频支持格式枚举、视频预览、视频录像、视频截图。Delphi 源代码
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【源码结构】
unit untUSBCamera;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, DirectShow9, ActiveX, Dialogs, StdCtrls, ExtCtrls;
type
PVideoInputInfo = ^TVideoInputInfo;
PVideoFormatInfo = ^TVideoFormatInfo;
{ 视频输入设备 }
TVideoInputInfo = record
id: TGUID;
strName: ShortString;
index: Integer;
end;
{ 视频支持格式 }
TVideoFormatInfo = record
id: TGUID;
iWidth, iHeight: Integer;
iMod: TGUID;
Frame: Int64;
format: ShortString;
end;
type
IAMStreamConfig = interface(IUnknown)
['{C6E13340-30AC-11d0-A18C-00A0C9118956}']
function SetFormat(const pmt: TAMMediaType): HResult; stdcall;
function GetFormat(out ppmt: PAMMediaType): HResult; stdcall;
function GetNumberOfCapabilities(out piCount, piSize: Integer): HResult; stdcall;
{ Delphi 声明有误，修改声明 }
function GetStreamCaps(iIndex: Integer; var ppmt: PAMMediaType; pSCC: PVideoStreamConfigCaps): HResult; stdcall;
end;
ISampleGrabber = interface(IUnknown)
['{6B652FFF-11FE-4FCE-92AD-0266B5D7C78F}']
function SetOneShot(OneShot: BOOL): HResult; stdcall;
{ Delphi 声明有误，修改声明 }
function SetMediaType(pType: PAMMediaType): HResult; stdcall;
function GetConnectedMediaType(out pType: TAMMediaType): HResult; stdcall;
function SetBufferSamples(BufferThem: BOOL): HResult; stdcall;
function GetCurrentBuffer(var pBufferSize: longint; pBuffer: Pointer): HResult; stdcall;
function GetCurrentSample(out ppSample: IMediaSample): HResult; stdcall;
function SetCallback(pCallback: ISampleGrabberCB; WhichMethodToCallback: longint): HResult; stdcall;
end;
{ 枚举所有视频输入设备 }
procedure EnumAllUSBCamera(strsList: TStrings);
{ 枚举视频支持格式 }
function EnumVideoFormat(const strFriendlyName: String; const intIndex: Integer; strsList: TStrings): Boolean;
{ 视频预览 }
function USBVideoPreview(var FIGraphBuilder: IGraphBuilder; var FICaptureGraphBuilder2: ICaptureGraphBuilder2; var FSysDevEnum: IBaseFilter; var FIVideoWindow: IVideoWindow; var FIMediaControl: IMediaControl; var FISampleGrabber: ISampleGrabber; pv: PVideoInputInfo; pf: PVideoFormatInfo; pnl: TPanel; const bSnapBmp: Boolean = False): Boolean;
{ 视频录制 }
function USBVideoRecord(var FIGraphBuilder: IGraphBuilder; var FICaptureGraphBuilder2: ICaptureGraphBuilder2; var FSysDevEnum: IBaseFilter; var FIVideoWindow: IVideoWindow; var FIMediaControl: IMediaControl; var FISampleGrabber: ISampleGrabber; pv: PVideoInputInfo; pf: PVideoFormatInfo; pnl: TPanel; const strSaveFileName: String): Boolean;
implementation
const
IID_IPropertyBag: TGUID = '{55272A00-42CB-11CE-8135-00AA004BB851}';
c_arrVideoFormatGUID: array [0 .. 35] of PGUID = ( //
@MEDIASUBTYPE_CLPL, @MEDIASUBTYPE_YUYV, @MEDIASUBTYPE_IYUV, @MEDIASUBTYPE_YVU9, @MEDIASUBTYPE_Y411, @MEDIASUBTYPE_Y41P, //
@MEDIASUBTYPE_YUY2, @MEDIASUBTYPE_YVYU, @MEDIASUBTYPE_UYVY, @MEDIASUBTYPE_Y211, @MEDIASUBTYPE_YV12, @MEDIASUBTYPE_CLJR, //
@MEDIASUBTYPE_IF09, @MEDIASUBTYPE_CPLA, @MEDIASUBTYPE_MJPG, @MEDIASUBTYPE_TVMJ, @MEDIASUBTYPE_WAKE, @MEDIASUBTYPE_CFCC, //
@MEDIASUBTYPE_IJPG, @MEDIASUBTYPE_Plum, @MEDIASUBTYPE_DVCS, @MEDIASUBTYPE_DVSD, @MEDIASUBTYPE_MDVF, @MEDIASUBTYPE_RGB1, //
@MEDIASUBTYPE_RGB4, @MEDIASUBTYPE_RGB8, @MEDIASUBTYPE_RGB565, @MEDIASUBTYPE_RGB555, @MEDIASUBTYPE_RGB24, @MEDIASUBTYPE_RGB32, //
@MEDIASUBTYPE_ARGB1555, @MEDIASUBTYPE_ARGB4444, @MEDIASUBTYPE_ARGB32, @MEDIASUBTYPE_AYUV, @MEDIASUBTYPE_AI44, @MEDIASUBTYPE_IA44 //
);
c_arrVideoFormatName: array [0 .. 35] of AnsiString = ( //
'CLPL', 'YUYV', 'IYUV', 'YVU9', 'Y411', 'Y41P', //
'YUY2', 'YVYU', 'UYVY', 'Y211', 'YV12', 'CLJR', //
'IF09', 'CPLA', 'MJPG', 'TVMJ', 'WAKE', 'CFCC', //
'IJPG', 'Plum', 'DVCS', 'DVSD', 'MDVF', 'RGB1', //
'RGB4', 'RGB8', 'RGB565', 'RGB555', 'RGB24', 'RGB32', //
'ARGB1555', 'ARGB4444', 'ARGB32', 'AYUV', 'AI44', 'IA44' //
);
function GetMaxIndex(const strsList: TStrings; const strUSBCameraName: string): Integer;
var
III, Count: Integer;
begin
Result := 0;
Count := strsList.Count;
for III := 0 to Count - 1 do
begin
if CompareText(String(PVideoInputInfo(strsList.Objects[III])^.strName), strUSBCameraName) = 0 then
begin
Result := Result 1;
end;
end;
end;
function CreateFilter(gid: TGUID; FriendlyName: AnsiString; instanceIndex: Integer): IBaseFilter;
var
pSysDevEnum: ICreateDevEnum;
pEnumCat : IEnumMoniker;
pMoniker : IMoniker;
cFetched : ULONG;
pPropBag : IPropertyBag;
bc : IBindCtx;
mo : IMoniker;
er : IErrorLog;
ov : OleVariant;
iIndex : Integer;
begin
Result := nil;
pSysDevEnum := nil;
pEnumCat := nil;
pMoniker := nil;
if CocreateInstance(CLSID_SystemDeviceEnum, nil, CLSCTX_INPROC, IID_ICreateDevEnum, pSysDevEnum) = S_OK then
begin
if pSysDevEnum.CreateClassEnumerator(gid, pEnumCat, 0) = S_OK then
begin
iIndex := 0;
while (pEnumCat.Next(1, pMoniker, @cFetched) = S_OK) and (cFetched > 0) and (pMoniker <> nil) do
begin
bc := nil;
mo := nil;
pMoniker.BindToStorage(bc, mo, IID_IPropertyBag, pPropBag);
er := nil;
pPropBag.Read('FriendlyName', ov, er);
if AnsiString(ov) = FriendlyName then
begin
if iIndex = instanceIndex then
begin
bc := nil;
mo := nil;
pMoniker.BindToObject(bc, mo, IID_IBaseFilter, Result);
end;
Inc(iIndex);
end;
pPropBag := nil;
pMoniker := nil;
end;
end;
end;
pEnumCat := nil;
pSysDevEnum := nil;
end;
function VideoMediaSubTypeToStr(mst: TGUID): AnsiString;
var
I: Integer;
begin
Result := '';
for I := 0 to 35 do
if CompareMem(c_arrVideoFormatGUID[I], @mst, sizeof(TGUID)) then
begin
Result := c_arrVideoFormatName[I];
break;
end;
end;
procedure FreeMediaType(mt: TAMMediaType);
begin
if (mt.cbFormat <> 0) then
begin
CoTaskMemFree(mt.pbFormat);
mt.cbFormat := 0;
mt.pbFormat := nil;
end;
if (mt.pUnk <> nil) then
begin
mt.pUnk := nil;
end;
end;
procedure DeleteMediaType(pmt: PAMMediaType);
begin
if pmt <> nil then
begin
FreeMediaType(pmt^);
CoTaskMemFree(pmt);
end;
end;
function GetOutputPin(filter: IBaseFilter): IPin;
var
penum: IEnumPins;
f : Integer;
d : PIN_DIRECTION;
begin
Result := nil;
filter.EnumPins(penum);
while (penum.Next(1, Result, @f) = S_OK) and (f > 0) do
begin
if (Result.QueryDirection(d) = S_OK) and (d = PINDIR_OUTPUT) then
begin
{ 找到输出接口，返回 }
Exit;
end;
end;
Result := nil;
end;
function StrToVideoMediaSubType(ss: AnsiString): TGUID;
var
I: Integer;
begin
Result := c_arrVideoFormatGUID[0]^;
for I := 0 to 35 do
if ss = c_arrVideoFormatName[I] then
begin
Result := c_arrVideoFormatGUID[I]^;
break;
end;
end;
function CompareGUID(const g1, g2: TGUID): Boolean;
begin
Result := CompareMem(@g1, @g2, sizeof(TGUID));
end;
function SetMediaType(filter: IBaseFilter; Width, Height: Integer; format: AnsiString): Boolean;
var
pmt : PAMMediaType;
piCount, piSize: Integer;
I : Integer;
pSCC : PVideoStreamConfigCaps;
streamConfig : IAMStreamConfig;
outPin : IPin;
formatID : TGUID;
selectedIndex : Integer;
ih : PVIDEOINFOHEADER;
bitRate : dword;
begin
Result := False;
if (Width = 0) or (Height = 0) then
Exit;
outPin := GetOutputPin(filter);
outPin.QueryInterface(IID_IAMStreamConfig, streamConfig);
if assigned(streamConfig) then
begin
selectedIndex := -1;
bitRate := 0;
formatID := StrToVideoMediaSubType(format);
streamConfig.GetNumberOfCapabilities(piCount, piSize);
getmem(pSCC, piSize);
try
for I := 0 to piCount - 1 do
begin
streamConfig.GetStreamCaps(I, pmt, pSCC);
ih := Pointer(pmt^.pbFormat);
if (pSCC^.MinOutputSize.cx = Width) and (pSCC^.MinOutputSize.cy = Height) and (ih^.bmiHeader.biWidth = Width) and (ih^.bmiHeader.biheight = Height) and ((format = '') or (CompareGUID(formatID, pmt^.subtype))) and (ih^.dwBitRate > bitRate) // select format with maximum bitrate
then
begin
selectedIndex := I;
bitRate := ih^.dwBitRate;
end;
DeleteMediaType(pmt);
end;
if selectedIndex > -1 then
begin
streamConfig.GetStreamCaps(selectedIndex, pmt, pSCC);
try
streamConfig.SetFormat(pmt^);
finally
DeleteMediaType(pmt);
end;
end;
finally
FreeMem(pSCC);
end;
end;
Result := True;
end;
{ 枚举所有视频输入设备 }
procedure EnumAllUSBCamera(strsList: TStrings);
var
SysDevEnum: ICreateDevEnum;
EnumCat : IEnumMoniker;
hr : Integer;
Moniker : IMoniker;
Fetched : ULONG;
PropBag : IPropertyBag;
strName : OleVariant;
strGuid : OleVariant;
III : Integer;
puInfo : PVideoInputInfo;
intIndex : Integer;
begin
{ 创建系统枚举器对象 }
hr := CocreateInstance(CLSID_SystemDeviceEnum, nil, CLSCTX_INPROC, IID_ICreateDevEnum, SysDevEnum);
if hr <> S_OK then
Exit;
{ 用指定的 Filter 目录类型创建一个枚举器，并获得 IEnumMoniker 接口； }
hr := SysDevEnum.CreateClassEnumerator(CLSID_VideoInputDeviceCategory, EnumCat, 0);
if hr <> S_OK then
Exit;
try
{ 释放内存 }
if strsList.Count > 0 then
begin
for III := 0 to strsList.Count - 1 do
begin
FreeMem(PVideoFormatInfo(strsList.Objects[III]));
end;
end;
strsList.Clear;
{ 获取指定类型目录下所有设备标识 }
while (EnumCat.Next(1, Moniker, @Fetched) = S_OK) do
begin
Moniker.BindToStorage(nil, nil, IID_IPropertyBag, PropBag);
PropBag.Read('CLSID', strGuid, nil);
PropBag.Read('FriendlyName', strName, nil);
New(puInfo);
puInfo^.id := TGUID(strGuid);
puInfo^.strName := ShortString(strName);
puInfo^.index := 0;
if strsList.IndexOf(strName) = -1 then
begin
strsList.AddObject(strName, TObject(puInfo));
end
else
begin
{ 相同名称的 USBCamera 相机，<有可能有多个名称重复的相机> }
intIndex := GetMaxIndex(strsList, strName);
puInfo^.index := intIndex 1;
strsList.AddObject(strName format('(%d)', [puInfo^.index]), TObject(puInfo));
end;
PropBag := nil;
Moniker := nil;
end;
finally
EnumCat := nil;
SysDevEnum := nil;
end;
end;
{ 枚举视频支持格式 }
function EnumVideoFormat(const strFriendlyName: String; const intIndex: Integer; strsList: TStrings): Boolean;
var
SysDevEnum : IBaseFilter;
CaptureGraphBuilder2: ICaptureGraphBuilder2;
iunk : IUnknown;
fStreamConfig : IAMStreamConfig;
piCount, piSize : Integer;
III : Integer;
pmt : PAMMediaType;
pSCC : PVideoStreamConfigCaps;
pvInfo : PVideoFormatInfo;
begin
Result := False;
{ 获取指定USB摄像头的 Filter }
SysDevEnum := CreateFilter(CLSID_VideoInputDeviceCategory, AnsiString(strFriendlyName), intIndex);
if SysDevEnum = nil then
Exit;
{ 释放内存 }
if strsList.Count > 0 then
begin
for III := 0 to strsList.Count - 1 do
begin
FreeMem(PVideoFormatInfo(strsList.Objects[III]));
end;
end;
strsList.Clear;
{ 创建 ICaptureGraphBuilder2 接口 }
if Failed(CocreateInstance(CLSID_CaptureGraphBuilder2, nil, CLSCTX_INPROC, IID_ICaptureGraphBuilder2, CaptureGraphBuilder2)) then
Exit;
{ 获取 IID_IAMStreamConfig 接口 }
if Failed(CaptureGraphBuilder2.FindInterface(nil, nil, SysDevEnum, IID_IAMStreamConfig, iunk)) then
Exit;
{ 获取 IAMStreamConfig 媒体类型接口 }
if Failed(iunk.QueryInterface(IID_IAMStreamConfig, fStreamConfig)) then
Exit;
if Failed(fStreamConfig.GetNumberOfCapabilities(piCount, piSize)) then
Exit;
if piCount <= 0 then
Exit;
{ 枚举支持的视频格式 }
pSCC := AllocMem(piSize);
try
for III := 0 to piCount - 1 do
begin
if fStreamConfig.GetStreamCaps(III, pmt, pSCC) = S_OK then
begin
try
New(pvInfo); { 注意释放内存 }
pvInfo^.Frame := PVIDEOINFOHEADER(pmt^.pbFormat)^.AvgTimePerFrame;
pvInfo^.id := pmt^.formattype;
pvInfo^.iWidth := pSCC^.MaxOutputSize.cx;
pvInfo^.iHeight := pSCC^.MaxOutputSize.cy;
pvInfo^.iMod := pmt^.subtype;
pvInfo^.format := VideoMediaSubTypeToStr(pmt^.subtype);
strsList.AddObject(format('类型：%s 分辨率：%4d×%4d', [pvInfo^.format, pvInfo^.iWidth, pvInfo^.iHeight]), TObject(pvInfo));
finally
DeleteMediaType(pmt);
end;
end;
end;
finally
FreeMem(pSCC);
end;
SysDevEnum := nil;
CaptureGraphBuilder2 := nil;
fStreamConfig := nil;
Result := True;
end;
function CommonVideo(var FIGraphBuilder: IGraphBuilder; //
var FICaptureGraphBuilder2: ICaptureGraphBuilder2; //
var FSysDevEnum: IBaseFilter; //
var FIVideoWindow: IVideoWindow; //
var FIMediaControl: IMediaControl; //
var FISampleGrabber: ISampleGrabber; //
pv: PVideoInputInfo; pf: PVideoFormatInfo; //
pnl: TPanel; //
const strSaveFileName: string = ''; const bRecord: Boolean = False; // 录像
const bSnapBmp: Boolean = False // 截图
): Boolean;
var
SampleGrabberFilter: IBaseFilter;
mt : TAMMediaType;
multiplexer : IBaseFilter;
Writer : IFileSinkFilter;
begin
Result := False;
{ 创建 IGraphBuilder 接口 }
if Failed(CocreateInstance(CLSID_FilterGraph, nil, CLSCTX_INPROC, IID_IGraphBuilder, FIGraphBuilder)) then
Exit;
{ 创建 ICaptureGraphBuilder2 接口 }
if Failed(CocreateInstance(CLSID_CaptureGraphBuilder2, nil, CLSCTX_INPROC, IID_ICaptureGraphBuilder2, FICaptureGraphBuilder2)) then
Exit;
{ 调用 ICaptureGraphBuilder2 的 SetFilterGraph 方法将 FilterGraph 加入到Builder中 }
if Failed(FICaptureGraphBuilder2.SetFiltergraph(FIGraphBuilder)) then
Exit;
{ 获取指定USB摄像头的 Filter }
FSysDevEnum := CreateFilter(CLSID_VideoInputDeviceCategory, AnsiString(pv^.strName), pv^.index);
if FSysDevEnum = nil then
Exit;
{ 设置指定 Filter 的媒体格式类型 }
if not SetMediaType(FSysDevEnum, pf^.iWidth, pf^.iHeight, pf^.format) then
Exit;
{ 将视频捕捉 Filter 添加到 Filter 图中 }
if Failed(FIGraphBuilder.AddFilter(FSysDevEnum, 'VideoCapture')) then
Exit;
{ 如果需要截图功能 }
if bSnapBmp then
begin
CocreateInstance(CLSID_SampleGrabber, nil, CLSCTX_INPROC, IID_IBaseFilter, SampleGrabberFilter);
FIGraphBuilder.AddFilter(SampleGrabberFilter, 'SampleGrabber');
SampleGrabberFilter.QueryInterface(IID_ISampleGrabber, FISampleGrabber);
zeromemory(@mt, sizeof(AM_MEDIA_TYPE));
mt.majortype := MEDIATYPE_Video;
mt.subtype := MEDIASUBTYPE_RGB24; // 24位，位图格式输出
FISampleGrabber.SetMediaType(@mt); //
FISampleGrabber.SetBufferSamples(True); // 允许从 Buffer 中获取数据
{ 渲染预览视频PIN }
if Failed(FICaptureGraphBuilder2.RenderStream(@PIN_CATEGORY_PREVIEW, @MEDIATYPE_Video, FSysDevEnum, SampleGrabberFilter, nil)) then
Exit;
end
else
begin
{ 渲染预览视频PIN }
if Failed(FICaptureGraphBuilder2.RenderStream(@PIN_CATEGORY_PREVIEW, @MEDIATYPE_Video, FSysDevEnum, nil, nil)) then
Exit;
end;
{ 如果是视频录制 }
if bRecord then
begin
{ 视频录制文件保持路径 }
if Failed(FICaptureGraphBuilder2.SetOutputFileName(MEDIASUBTYPE_Avi, PWideChar(strSaveFileName), multiplexer, Writer)) then
Exit;
if Failed(FICaptureGraphBuilder2.RenderStream(@PIN_CATEGORY_CAPTURE, @MEDIATYPE_Video, FSysDevEnum, nil, multiplexer)) then
Exit;
end;
{ 设置视频预览窗口 }
if Failed(FIGraphBuilder.QueryInterface(IID_IVideoWindow, FIVideoWindow)) then
Exit;
{ 设置视频播放的WINDOWS窗口 }
if Failed(FIVideoWindow.put_Owner(pnl.Handle)) then
Exit;
if Failed(FIVideoWindow.put_windowstyle(WS_CHILD or WS_Clipsiblings)) then
Exit;
{ 设置视频尺寸 }
if Failed(FIVideoWindow.SetWindowposition(0, 0, pnl.Width, pnl.Height)) then
Exit;
{ 得到IMediaControl接口，用于控制流播放 }
if Failed(FIGraphBuilder.QueryInterface(IID_IMediaControl, FIMediaControl)) then
Exit;
Result := True;
end;
{ 视频预览 }
function USBVideoPreview(var FIGraphBuilder: IGraphBuilder; var FICaptureGraphBuilder2: ICaptureGraphBuilder2; var FSysDevEnum: IBaseFilter; var FIVideoWindow: IVideoWindow; var FIMediaControl: IMediaControl; var FISampleGrabber: ISampleGrabber; pv: PVideoInputInfo; pf: PVideoFormatInfo; pnl: TPanel; const bSnapBmp: Boolean = False): Boolean;
begin
Result := CommonVideo(FIGraphBuilder, FICaptureGraphBuilder2, FSysDevEnum, FIVideoWindow, FIMediaControl, FISampleGrabber, pv, pf, pnl, '', False, True);
end;
{ 视频录制 }
function USBVideoRecord(var FIGraphBuilder: IGraphBuilder; var FICaptureGraphBuilder2: ICaptureGraphBuilder2; var FSysDevEnum: IBaseFilter; var FIVideoWindow: IVideoWindow; var FIMediaControl: IMediaControl; var FISampleGrabber: ISampleGrabber; pv: PVideoInputInfo; pf: PVideoFormatInfo; pnl: TPanel; const strSaveFileName: String): Boolean;
begin
Result := CommonVideo(FIGraphBuilder, FICaptureGraphBuilder2, FSysDevEnum, FIVideoWindow, FIMediaControl, FISampleGrabber, pv, pf, pnl, strSaveFileName, True, True);
end;
end.
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