我正在使用ASF Writer将原始AVI文件压缩为WMV。 我非常需要加快压缩速度。 有任何提示＆amp;关于如何实现这一目标的最佳实践？降低/降低索引器的影响？任何隐藏的压缩参数？
这些文件只包含RGB / 24bits格式的视频，视频流的压缩级别介于200kbps和2000kbps之间。
任何配置提示（使用C ++，C＃，Delphi等）
以下是配置WMV编写器的代码部分（使用DSPack）。
function CreateWMVWriter(VideoQuality, AudioQuality: Cardinal; videoInfo: PVideoInfoHeader; audioInfo: PWaveFormatEx; hasAudio: Boolean): IBaseFilter;
const
PROFILE_NAME = 'WMV AutoProfile';
// BUFFER_WINDOW = $FFFFFFFF; // auto buffer
BUFFER_WINDOW = 1000; // 1 second
MAX_KEY_FRAME_SPACING = 10000000; // 1 seconds
var
configWriter : IConfigAsfWriter;
profileManager : IWMProfileManager;
profile : IWMProfile;
stream : IWMStreamConfig;
mediaProps : IWMMediaProps;
vmediaProps : IWMVideoMediaProps;
pmt : PWMMediaType;
msize : Cardinal;
vih : PVideoInfoHeader;
wfe: PWaveFormatEx;
hr : HRESULT;
videoBitRate, audioBitRate: Cardinal;
width, height: Integer;
begin
videoBitRate := VideoQuality * 1000; // kbits
// create the profile
CheckDSError(WMCreateProfileManager(profileManager));
CheckDSError(profileManager.CreateEmptyProfile(WMT_VER_9_0, profile));
CheckDSError(profile.SetName(StringToOleStr(PROFILE_NAME)));
CheckDSError(profile.SetDescription(StringToOleStr(PROFILE_NAME)));
CheckDSError(profile.CreateNewStream(WMMEDIATYPE_Video, stream));
CheckDSError(stream.SetStreamName(StringToOleStr('Video')));
CheckDSError(stream.SetBitrate(videoBitRate));
CheckDSError(stream.SetBufferWindow(BUFFER_WINDOW));
// config video media type
stream.QueryInterface(IID_IWMMediaProps, mediaProps);
CheckDSError(mediaProps.GetMediaType(nil, msize));
GetMem(pmt, msize);
CheckDSError(mediaProps.GetMediaType(pmt, msize));
with pmt^ do
begin
majortype := WMMEDIATYPE_Video;
subtype := WMMEDIASUBTYPE_WMV3;
bFixedSizeSamples := True;
bTemporalCompression := True;
pUnk := nil;
vih := PVideoInfoHeader(pbFormat);
// copy video info header (the same as with the original - copy: rcSource, rcTarget, AvgTimePerFrame, biWidth, biHeight)
CopyMemory(vih, videoInfo, SizeOf(TVideoInfoHeader));
// set bit rate at the same value
vih.dwBitRate := videoBitRate;
// set new compression ('WMV3')
vih.bmiHeader.biCompression := MAKEFOURCC('W', 'M', 'V', '3');
end;
CheckDSError(mediaProps.SetMediaType(pmt));
FreeMem(pmt, msize);
// set media props
stream.QueryInterface(IID_IWMVideoMediaProps, vmediaProps);
CheckDSError(vmediaProps.SetQuality(100));
CheckDSError(vmediaProps.SetMaxKeyFrameSpacing(0));
// CheckDSError(vmediaProps.SetMaxKeyFrameSpacing(MAX_KEY_FRAME_SPACING));
// add video stream
CheckDSError(profile.AddStream(stream));
// add audio stream (if needed)
if hasAudio then
begin
CheckDSError(profile.CreateNewStream(WMMEDIATYPE_Audio, stream));
CheckDSError(stream.SetStreamName(StringToOleStr('Audio')));
audioBitRate := audioInfo.nSamplesPerSec * audioInfo.nChannels * audioInfo.wBitsPerSample;
CheckDSError(stream.SetBitrate(audioBitRate));
CheckDSError(stream.SetBufferWindow(BUFFER_WINDOW)); // auto
// config video media type
stream.QueryInterface(IID_IWMMediaProps, mediaProps);
CheckDSError(mediaProps.GetMediaType(nil, msize));
GetMem(pmt, msize);
hr := mediaProps.GetMediaType(pmt, msize);
with pmt^ do
begin
// uncompressed audio
majortype := WMMEDIATYPE_Audio;
subtype := WMMEDIASUBTYPE_PCM;
formattype := WMFORMAT_WaveFormatEx;
cbFormat := sizeof(TWaveFormatEx);
bFixedSizeSamples := True;
bTemporalCompression := False;
lSampleSize := audioInfo.nChannels * audioInfo.wBitsPerSample div 8;
pUnk := nil;
wfe := PWaveFormatEx(pbFormat);
// copy video info header (the same as with the original)
CopyMemory(wfe, audioInfo, SizeOf(TWaveFormatEx));
end;
CheckDSError(mediaProps.SetMediaType(pmt));
FreeMem(pmt, msize);
// add video stream
CheckDSError(profile.AddStream(stream));
end;
// create the writer
Result := AddFilterGUID(CLSID_WMAsfWriter, 'WmvWriter');
// config the writer
configWriter := Result as IConfigAsfWriter;
CheckDSError(configWriter.SetIndexMode(True));
CheckDSError(configWriter.ConfigureFilterUsingProfile(profile));
end;