以下是dspack中的DSPACK234\Demos\D6-D7\videocap例子，但是我指定的影像的解析度为何只能在capture可以，
preview的仍是320X240呢，哪好心人帮帮忙看一下，如何才能更改 preview的解析度?
var
multiplexer: IBaseFilter;
Writer: IFileSinkFilter;
PinList: TPinList;
i: integer;
begin

// Activate the filter graph, at this stage the source filters are added to the graph
CaptureGraph.Active := true;

// configure output Audio media type source
if AudioSourceFilter.FilterGraph <> nil then
begin
PinList := TPinList.Create(AudioSourceFilter as IBaseFilter);
i := 0;
while i < PinList.Count do
if PinList.PinInfo[i].dir = PINDIR_OUTPUT then
begin
if AudioFormats.ItemIndex <> -1 then
with (PinList.Items[i] as IAMStreamConfig) do
SetFormat(AudioMediaTypes.Items[AudioFormats.ItemIndex].AMMediaType^);
PinList.Delete(i);
end else inc(i);
if InputLines.ItemIndex <> -1 then
with (PinList.Items[InputLines.ItemIndex] as IAMAudioInputMixer) do
put_Enable(true);
PinList.Free;
end;

// configure output Video media type
if VideoSourceFilter.FilterGraph <> nil then
begin
PinList := TPinList.Create(VideoSourceFilter as IBaseFilter);
if VideoFormats.ItemIndex <> -1 then
(PinList.First as IAMStreamConfig).
with (PinList.First as IID_IAMStreamConfig) do
SetFormat(VideoMediaTypes.Items[VideoFormats.ItemIndex].AMMediaType^);
PinList.Free;
end;


// now render streams
with CaptureGraph as IcaptureGraphBuilder2 do
begin
// set the output filename
SetOutputFileName(MEDIASUBTYPE_Avi, PWideChar(CapFile), multiplexer, Writer);

// Connect Video preview (VideoWindow)
if VideoSourceFilter.BaseFilter.DataLength > 0 then
RenderStream(@PIN_CATEGORY_PREVIEW, nil, VideoSourceFilter as IBaseFilter,
SampleGrabber1 as IBaseFilter , VideoWindow as IBaseFilter);

// Connect Video capture streams
if VideoSourceFilter.FilterGraph <> nil then
RenderStream(@PIN_CATEGORY_CAPTURE, nil, VideoSourceFilter as IBaseFilter,
nil, multiplexer as IBaseFilter);

//Connect Audio capture streams
if AudioSourceFilter.FilterGraph <> nil then
begin

RenderStream(nil, nil, AudioSourceFilter as IBaseFilter,
nil, multiplexer as IBaseFilter);
end;
end;
CaptureGraph.Play;
StopButton.Enabled := true;
StartButton.Enabled := false;
AudioFormats.Enabled := false;
AudioCapFilters.Enabled := false;
VideoFormats.Enabled := false;
VideoCapFilters.Enabled := false;
Timer.Enabled := true;
end;

以下是我在DSPCK的http://progdigy.com   网站台上找到的,看来不是我一个人发现这个问题，肯定有人解决这个问题了，
就行行好帮帮我吧！
//===============
hi,guys
what's up!
there are some problems in my recent project development.
i use averEZcapture video card in my project,and i want set the video size 320X240 on the
preview pin and 768*576 on the capture pin!
but i can't preview the video well(i render it onto the videorender filter),it's quite freeze.
but the capture pin work well(i render it onto the null render filter,and it can grabber the sample with 768*576);
i just want to it's possible to render output different video size on preview pin and capture
pin,if can,how ?
thank u!
and my source code just like below :

Graphabuilder.findinterface(@PIN_CATEGORY_CAPTURE,........);captureconfig
//get the Iamstreamconfig on the Preview pin
// set the am_media_type each
captureconfig.setformat();
previewconfig.setformat();

看来还是没个回我的问题，自已解决了
procedure TVideoForm.SetVideoConfig( CaptureGraph : ICaptureGraphBuilder2; pCategory : PGUID;
SourceFilter : IBaseFilter; W,H,BitCount : integer );
var
StreamConf : IAMStreamConfig;
hr : HRESULT;
pmt : PAMMediaType;
scc : VIDEO_STREAM_CONFIG_CAPS;
pVIH : PVIDEOINFOHEADER;

Count, Size, iFormat : Integer;
begin

hr:= CaptureGraph.FindInterface(pCategory, @MEDIATYPE_Video, SourceFilter, IID_IAMStreamConfig, StreamConf);
if SUCCEEDED(hr) then begin

iFormat:=0; Count:=0; Size:=0;
hr:= StreamConf.GetNumberOfCapabilities(Count, Size);

for iFormat:=0 to Count-1 do begin

// Get the format
hr:= StreamConf.GetStreamCaps(iFormat, pmt, scc);
if SUCCEEDED(hr) then begin
// Modify the format block.

if ( IsEqualGUID(pmt.majortype,MEDIATYPE_Video) and
IsEqualGUID(pmt.subtype, MEDIASUBTYPE_RGB24) and
IsEqualGUID(pmt.formattype, FORMAT_VideoInfo) and
(pmt.cbFormat >= sizeof (VIDEOINFOHEADER)) and
(pmt.pbFormat <> nil) ) then begin


PVIDEOINFOHEADER(pmt^.pbFormat)^.bmiHeader.biWidth := W;
PVIDEOINFOHEADER(pmt^.pbFormat)^.bmiHeader.biHeight := H;
//PVIDEOINFOHEADER(pmt^.pbFormat)^.bmiHeader.biBitCount := BitCount;

// Set the sample size and image size.
// (Be sure to round the image width up to four.) //((W 3) & ~3) * height * cbPixel;
//pmt^.lSampleSize:=((W 3) and (not(3))) * H;
//PVIDEOINFOHEADER(pmt^.pbFormat)^.bmiHeader.biSizeImage:=((W 3) and (not(3))) * H;

// Now set the format.
hr := StreamConf.SetFormat(pmt^);
if (FAILED(hr)) then
MessageBox(NULL, 'SetFormat() Failed!', '', MB_OK);

end;

end;
DeleteMediaType(pmt);

end;

end;

StreamConf := nil;

end;