如何在捕获过滤器上的 DirectShow put_Enable 调用期间调试未指定的错误 ($80004005)？

Question

我有一个使用 DSPACK 组件库用 Delphi 6 编写的 DirectShow 应用程序。我在启用过滤器上的输入行时遇到一个奇怪的问题。我搜索引脚，直到找到输入线（在本例中名为“麦克风”），并在过滤器图处于活动状态时对其调用 put_Enable(true)。当我这样做时，我得到一个 $80004005“未指定错误”作为 HRESULT。

我在启用输入线之前设置过滤器的输出音频媒体类型，但有些东西无法正常工作。我用来创建应用程序的原始 DirectShow 示例运行良好。我相信我正在按照完全相同的步骤构建过滤器图，当然我可能错过了一些东西。有谁对我可以尝试解决此问题有任何提示或想法吗？下面的代码片段部分显示了我正在做的事情，但并不是导致它的所有步骤，因为它们非常冗长。我用于测试的捕获设备是一个 VOIP 耳机，带有一条名为“麦克风”的单输入线。

// The function I call to find an enable the first input line I find in the filter.
function findAndEnableFirstInputLineFound(intfBaseFilter: IBaseFilter; out strInputLineUsed: string): boolean;
var
    thePinList: TPinList;
    i: integer;
    ABool: LongBool;
begin
    strInputLineUsed := '';

    if not Assigned(intfBaseFilter) then
        raise Exception.Create('(findAndEnableFirstInputLineFound) The base filter interface object is unassigned.');

    // Now enable the first input source we can find.
    Result := false;
    thePinList := TPinList.Create(intfBaseFilter);

    try
        if thePinList.Count > 0 then
        begin
            // Scan the pin list looking for an input pin.
            i := 0;

            while (i < thePinList.Count) and (not Result) do
            begin
                if thePinList.PinInfo[i].dir = PINDIR_INPUT then
                begin
                    // Found one.  Enable it.
                    with thePinList.Items[i] as IAMAudioInputMixer do
                    begin
                        CheckDSEror(put_Enable(true)); // $80004005 error occurs here.

                        // Return the name of the input line used.
                        strInputLineUsed := thePinList.PinInfo[i].achName;
                    end; // with thePinList.Items[i] as IAMAudioInputMixer do

                    Result := true;
                    break; // Stop looping.
                end; // if thePinList.PinInfo[i].dir = PINDIR_INPUT then

                Inc(i);
            end; // while()
        end; // if thePinList.Count > 0 then
    finally
        thePinList.Free;
    end; // try
end;


// The initialization procedure that calls the function above.  It is run after the
//  the Filter Graph is activated but before it is played.
procedure TDXChain_wavaudio.initializeCaptureFilter;
var
    theMediaType: TMediaType;
    intfCapturePin: IPin;
    aryEnabledInputLines: TDynamicStringArray;
begin
    theMediaType := nil;
    intfCapturePin := nil;
    aryEnabledInputLines := nil;

    if not FFilterGraph.Active then
        raise Exception.Create('(TDXChain_wavaudio.Create::initializeCaptureFilter) The Filter Graph is INACTIVE.');

    if Assigned(FCaptureFilter) then
    begin

        // Make sure the Capture Filter's output pins supports the
        //   configured WAV format.
        with FOwner.ati_WaveFormatEx do
        begin
            // if not Assigned(findAudioMediaTypeByFormat(FCaptureFilter_mediatypes, nSamplesPerSec, wBitsPerSample, nChannels)) then
            theMediaType := findAudioMediaTypeExt_outputs(FCaptureFilter as IBaseFilter, nSamplesPerSec, wBitsPerSample, nChannels);

            if not Assigned(theMediaType) then
                // The capture device does not directly support the desired
                //  WAV format.  This is not allowed currently.
                raise Exception.Create('(TDXChain_wavaudio.Create::initializeCaptureFilter) The audio input device''s output pins does not support the given WAV format: '
                        + CRLF
                        + Format('(Device name: %s, Sample Rate: %d, Bits Per Sample: %d, Number of Channels: %d)',
                                    [FOwner.FCaptureFilterConfigInfo.filterName, nSamplesPerSec, wBitsPerSample, nChannels])
                    );

            // -------------- SET OUTPUT PINS TO MEDIA TYPE -------------

            // Set the output pins to the desired format.
            setPinAudMediaType_outputs(FCaptureFilter, theMediaType.AMMediaType);

            // Don't need the media type anymore.
            FreeAndNil(theMediaType);
        end; // with FOwner.ati_WaveFormatEx do

        // Enable at least one input line.
        if FOwner.FCaptureFilterConfigInfo.inputPinName = '' then
        begin
            //  No input name was specified so use the first one found.
            if not findAndEnableFirstInputLineFound(FCaptureFilter as IBaseFilter, FOwner.FInputLineUsed) then
                raise Exception.Create(
                    '(TDXChain_wavaudio.Create::initializeCaptureFilter) Unable to find a suitable input line for the audio input device named: '
                    + FOwner.FCaptureFilterConfigInfo.filterName);
        end
        else
        begin
            // Now find the desired available input line and enable it.
            if not findAndEnableInputLineByName(FOwner.FCaptureFilterConfigInfo.inputPinName, FCaptureFilter as IBaseFilter, FOwner.FInputLineUsed) then
                raise Exception.Create(
                    '(TDXChain_wavaudio.Create::initializeCaptureFilter) Unable to find the input line named ('
                    + FOwner.FCaptureFilterConfigInfo.inputPinName
                    + ') for the audio input device named: '
                    + FOwner.FCaptureFilterConfigInfo.filterName);
        end; // else - if FOwner.FCaptureFilterConfigInfo.inputPinName = '' then

        aryEnabledInputLines := getEnabledInputLineNames(FCaptureFilter as IBaseFilter);

        if Length(aryEnabledInputLines) < 1 then
            raise Exception.Create('(TDXChain_wavaudio.Create::initializeCaptureFilter) No input lines are enabled..');

        // ------------------ BUFFER LATENCY --------------------

        // Get a reference to the output pin for audio the capture device.
        with FCaptureFilter as IBaseFilter do
            CheckDSError(findPin(StringToOleStr('Capture'), intfCapturePin));

        if not Assigned(intfCapturePin) then
            raise Exception.Create('(TDXChain_wavaudio.Create::initializeCaptureFilter) Unable to find the audio input device''s Capture output pin.');

        // Set the capture device buffer to 50 ms worth of audio data to
        //  reduce latency.  NOTE: This will fail if the device does not
        //  support the latency you desire so make sure you watch out for that.
        setBufferLatency(intfCapturePin as IAMBufferNegotiation, FOwner.ati_BufferLatency_ms, FOwner.FMediaType);
    end; // if Assigned(FCaptureFilter) then
end;

Answer 1

我认为音频捕获过滤器在尝试启用某些引脚以混合到录音中时依赖于底层硬件和驱动程序。如果底层因错误而失败，则会将此错误转发给您。

据猜测，当您尝试在另一个引脚已启用的情况下启用一个引脚时，捕获硬件可能会指示错误，即它实际上无法混合两者。