未压缩的视频样本（IMFSample / RGB32）到位图缩略图 [英] Uncompressed video sample (IMFSample/RGB32) to bitmap thumbnail
问题描述
我正在尝试在Windows运行时C ++项目中为视频生成缩略图。我将输入视频文件作为IRandomAccessStream作为参数传递。我能够使用SourceReader获取IMFSamples，但我不知道如何将数据传回调用者
作为在XAML / C＃app中使用的图像缩略图。
请忽略一些硬编码值，为简单起见，我只是在第0.5个标记处获得第一个缩略图。我不确定从IMFSample转换为WriteBitmap的最佳方法是什么。这是我到目前为止所尝试的...如果我的方向正确，我甚至不会确定
...
IAsyncOperation < WriteableBitmap ^> ^
MediaTransformer :: GenerateThumbnailAsync（ IRandomAccessStream ^
inputStream ）
< p style ="margin-bottom：0px; font-size：9.5px; line-height：normal; font-family：Consolas">
{
WriteableBitmap ^位图=
ref new
WriteableBitmap （1280,720）;
IUnknown * pUnknown =
reinterpret_cast < IUnknown *>（位图 - > PixelBuffer）;
IBufferByteAccess * pBufferByteAccess =
nullptr ;
CHK （pUnknown-> QueryInterface（ IID_PPV_ARGS （& pBufferByteAccess）））;
&NBSP; pUnknown-> Release（）;
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; return create_async（[ this ，bitmap，pBufferByteAccess，inputStream]（ cancellation_token
令牌） - > WriteableBitmap ^
; {
;
HRESULT hr = S_OK ;
& NBSP;&NBSP;&NBSP;
AutoMF mf;
//
&NBSP;&NBSP;&NBSP;
//创建ReadWriteClassFactory
//
CoCreateInstance（CLSID_MFReadWriteClassFactory，
NULL ， CLSCTX_INPROC_SERVER ，IID_IMFReadWriteClassFactory，（ void **）（& spClassFactory））;
//
的&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; &NBSP;&NBSP;&NBSP;
//创建源阅读器
//
ComPtr < IMFByteStream > spInputByteStream;
;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
CHK （MFCreateMFByteStreamOnStreamEx（（ IUnknown *） inputStream ，& spInputByteStream））;
ComPtr < IMFAttributes > spReaderAttributes;
;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
CHK （MFCreateAttributes（& spReaderAttributes，10））;
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
CHK （spReaderAttributes-> SetUINT32（MF_SOURCE_READER_ENABLE_ADVANCED_VIDEO_PROCESSING，
true ） ）;
;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
CHK （spReaderAttributes-> SetUINT32（MF_READWRITE_ENABLE_HARDWARE_TRANSFORMS，
true ） ）;
;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
CHK （spClassFactory-> CreateInstanceFromObject（CLSID_MFSourceReader，spInputByteStream.Get（），spReaderAttributes.Get（），IID_IMFSourceReader，& spSourceReader））;
;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
ComPtr < IMFMediaType > spType =
NULL ;
&NBSP;&NBSP;&NBSP;&NBSP;
//配置源阅读器以提供渐进式RGB32帧。
&NBSP;&NBSP;&NBSP;
//如果需要，源阅读器将加载解码器。
CHK （MFCreateMediaType（& spType））;
CHK （spType-> SetGUID（MF_MT_MAJOR_TYPE，MFMediaType_Video））
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;
CHK （spType-> SetGUID（MF_MT_SUBTYPE，MFVideoFormat_RGB32））;
&NBSP;
CHK （spSourceReader-> SetCurrentMediaType（
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;（的 DWORD ） MF_SOURCE_READER_FIRST_VIDEO_STREAM ，
;
NULL ，
;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; spType.Get（）））;
的
CHK （spSourceReader-> SetStreamSelection（
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;（的 DWORD ） MF_SOURCE_READER_FIRST_VIDEO_STREAM ，
;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
的 TRUE ））;
&nbs p;
// hr = GetVideoFormat（& m_format）;
BOOL bCanSeek = FALSE ;
LONGLONG hnsDuration = 0;
LONGLONG hnsRangeStart = 0;
LONGLONG hnsRangeEnd = 0;
LONGLONG hnsIncrement = 5000000;
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;的
CHK （CanSeek（& bCanSeek））;
if （bCanSeek）
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; {
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;
的 CHK （的 MediaTransformer :: GetDuration（spSourceReader.Get（），&安培; hnsDuration））;
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;
// hnsRangeStart = 0;
的&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;
// hnsRangeEnd = hnsDuration;
的&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;
////我们有文件持续时间，因此我们将从
的&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;
////文件中的多个位置。偶尔，第一帧
的&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;
////在视频中是黑色的，所以我们不会在0时开始。
的&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
// hnsIncrement =（hnsRangeEnd - hnsRangeStart）/（5 + 1）;
}
LONGLONG hnsPos = hnsIncrement;
DWORD dwFlags = 0;
字节&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; * pBitmapData = <跨度风格= "颜色：＃84219c">
NULL ;&NBSP;&NBSP;&NBSP ; //位图数据
DWORD cbBitmapData = 0; // Size of size数据，以字节为单位
LONGLONG hnsTimeStamp = 0;
DWORD cSkipped = 0;
//跳过的帧数
DWORD streamIndex = 0;
IMFSample * pSample = NULL ;
IMFMediaBuffer * pBuffer = 0;
IMF2DBuffer2 * pImageBuffer = 0;
// ID2D1Bitmap * pBitmap = NULL;
LONG strideSize = 0;
DWORD bufferLength = 0;
BYTE * pBufferStart;
if （bCanSeek&&（hnsPos> 0））
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; {
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;
PROPVARIANT var;
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ; PropVariantInit（& var）;
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ; var.vt =
VT_I8 ;
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ; var.hVal.QuadPart = hnsPos;
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;
的 CHK （spSourceReader-> SetCurrentPosition（GUID_NULL，VAR））;
}
//从源阅读器中拉出视频帧。
//注意：根据容器的不同，寻求可能不准确
// 格式以及文件的索引方式。因此，第一个
// 我们获得的框架可能早于所需的时间。
// 如果是这样，我们会跳过最多MAX_FRAMES_TO_SKIP帧。
while （1）
{
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;
IMFSample * pSampleTmp =
NULL ;
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ; hr = spSourceReader-> ReadSample（
（ DWORD ） MF_SOURCE_READER_FIRST_VIDEO_STREAM ，
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ; 0，
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;&NBSP;&NBSP;&NBSP;&NBSP; & streamIndex，
;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; & dwFlags，
;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
NULL ，
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; & pSampleTmp
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; ）;
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
if （ FAILED （hr））{
转到完成; }
;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
if （dwFlags&
MF_SOURCE_READERF_ENDOFSTREAM ）
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; {
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
break ;
&NBSP;&NBSP; }
MF_SOURCE_READERF_CURRENTMEDIATYPECHANGED ）
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; {
< span style ="color：＃000000"> &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
'跨度风格= "颜色：＃000000">&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP ;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
if （ FAILED （hr））{
转到完成; }
&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP; }
;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;
if （pSampleTmp ==
NULL ）
{
continue;
}
// We got a sample. Hold onto it.
SafeRelease(&pSample);
pSample = pSampleTmp;
pSample->AddRef();
if (SUCCEEDED( pSample->GetSampleTime(&hnsTimeStamp) ))
{
// Keep going until we get a frame that is within tolerance of the
// desired seek position, or until we skip MAX_FRAMES_TO_SKIP frames.
// During this process, we might reach the end of the file, so we
// always cache the last sample that we got (pSample).
if ( (cSkipped < MAX_FRAMES_TO_SKIP) &&
(hnsTimeStamp + SEEK_TOLERANCE < hnsPos) )
{
SafeRelease(&pSampleTmp);
++cSkipped;
continue;
}
}
SafeRelease(&pSampleTmp);
hnsPos = hnsTimeStamp;
break;
}
if (pSample)
{
CHK(pSample->ConvertToContiguousBuffer(&pBuffer));
CHK(pBuffer->QueryInterface(IID_IMF2DBuffer2, (void**)&pImageBuffer));
hr = pImageBuffer->Lock2DSize(MF2DBuffer_LockFlags_Read, &pBitmapData, &strideSize, &pBufferStart,
&bufferLength);
hr = pBufferByteAccess->Buffer(&pBitmapData);
CHK(MFCopyImage(pBitmapData, 0, pBufferStart, strideSize, 1280, 720));
}
else
{
hr =
MF_E_END_OF_STREAM;
}
done:
if (pBitmapData)
{
pImageBuffer->Unlock2D();
}
SafeRelease(&pBuffer);
SafeRelease(&pSample);
SafeRelease(&pImageBuffer);
SafeRelease(&pBufferStart);
return bitmap;
});
}
I didn’t run your code, it looks similar to how I would do it.
One note though...
As far as I know for gpu acceleration (or at least to have control of your d3d device), the IMFSourceReader needs a IMFDXGIManager initialized (ResetDevice) with a D3D device (with ID3D10Multithread::SetMultithread(TRUE)
). The IMFDXGIManager will be set to your spReaderAttributes with the MF_SOURCE_READER_D3D_MANAGER key.
Also you can get a IMFDXGIBuffer from your sample and render it using a SurfaceImageSource (D3D interop with xaml).
I am trying to generate thumbnails for a video in Windows Runtime C++ Project. I am passing in the input video file as IRandomAccessStream as a parameter. I am able to get IMFSamples using SourceReader but I am not sure how to pass back the data to the caller as an image thumbnail to be consumed in XAML/C# app.
Please disregard some of the hard-coded values and for simplicity reasons, I am just getting the first thumbnail at around 0.5 sec mark. I wasn't sure what the best way to convert from IMFSample to WriteBitmap was. Here's what I've tried so far... not even sure if I am in the right direction...
IAsyncOperation<WriteableBitmap^>^ MediaTransformer::GenerateThumbnailAsync(IRandomAccessStream^ inputStream)
{
WriteableBitmap^ bitmap = ref new WriteableBitmap(1280, 720);
IUnknown* pUnknown = reinterpret_cast<IUnknown*>(bitmap->PixelBuffer);
IBufferByteAccess* pBufferByteAccess = nullptr;
CHK(pUnknown->QueryInterface(IID_PPV_ARGS(&pBufferByteAccess)));
pUnknown->Release();
return create_async([this, bitmap, pBufferByteAccess, inputStream](cancellation_token token) -> WriteableBitmap^
{
HRESULT hr = S_OK;
AutoMF mf;
//
// Create the ReadWriteClassFactory
//
CoCreateInstance(CLSID_MFReadWriteClassFactory, NULL, CLSCTX_INPROC_SERVER, IID_IMFReadWriteClassFactory, (void**)(&spClassFactory));
//
// Create the Source Reader
//
ComPtr<IMFByteStream> spInputByteStream;
CHK(MFCreateMFByteStreamOnStreamEx((IUnknown*)inputStream, &spInputByteStream));
ComPtr<IMFAttributes> spReaderAttributes;
CHK(MFCreateAttributes(&spReaderAttributes, 10));
CHK(spReaderAttributes->SetUINT32(MF_SOURCE_READER_ENABLE_ADVANCED_VIDEO_PROCESSING, true));
CHK(spReaderAttributes->SetUINT32(MF_READWRITE_ENABLE_HARDWARE_TRANSFORMS, true));
CHK(spClassFactory->CreateInstanceFromObject(CLSID_MFSourceReader, spInputByteStream.Get(), spReaderAttributes.Get(), IID_IMFSourceReader, &spSourceReader));
ComPtr<IMFMediaType> spType = NULL;
// Configure the source reader to give us progressive RGB32 frames.
// The source reader will load the decoder if needed.
CHK(MFCreateMediaType(&spType));
CHK(spType->SetGUID(MF_MT_MAJOR_TYPE, MFMediaType_Video))
CHK(spType->SetGUID(MF_MT_SUBTYPE, MFVideoFormat_RGB32));
CHK(spSourceReader->SetCurrentMediaType(
(DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM,
NULL,
spType.Get()));
CHK(spSourceReader->SetStreamSelection(
(DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM,
TRUE));
//hr = GetVideoFormat(&m_format);
BOOL bCanSeek = FALSE;
LONGLONG hnsDuration = 0;
LONGLONG hnsRangeStart = 0;
LONGLONG hnsRangeEnd = 0;
LONGLONG hnsIncrement = 5000000;
CHK(CanSeek(&bCanSeek));
if (bCanSeek)
{
CHK(MediaTransformer::GetDuration(spSourceReader.Get(), &hnsDuration));
//hnsRangeStart = 0;
//hnsRangeEnd = hnsDuration;
//// We have the file duration , so we'll take bitmaps from
//// several positions in the file. Occasionally, the first frame
//// in a video is black, so we don't start at time 0.
//hnsIncrement = (hnsRangeEnd - hnsRangeStart) / (5 + 1);
}
LONGLONG hnsPos = hnsIncrement;
DWORD dwFlags = 0;
BYTE *pBitmapData = NULL; // Bitmap data
DWORD cbBitmapData = 0; // Size of data, in bytes
LONGLONG hnsTimeStamp = 0;
DWORD cSkipped = 0; // Number of skipped frames
DWORD streamIndex = 0;
IMFSample *pSample = NULL;
IMFMediaBuffer *pBuffer = 0;
IMF2DBuffer2 *pImageBuffer = 0;
//ID2D1Bitmap *pBitmap = NULL;
LONG strideSize = 0;
DWORD bufferLength = 0;
BYTE *pBufferStart;
if (bCanSeek && (hnsPos > 0))
{
PROPVARIANT var;
PropVariantInit(&var);
var.vt = VT_I8;
var.hVal.QuadPart = hnsPos;
CHK(spSourceReader->SetCurrentPosition(GUID_NULL, var));
}
// Pulls video frames from the source reader.
// NOTE: Seeking might be inaccurate, depending on the container
// format and how the file was indexed. Therefore, the first
// frame that we get might be earlier than the desired time.
// If so, we skip up to MAX_FRAMES_TO_SKIP frames.
while (1)
{
IMFSample *pSampleTmp = NULL;
hr = spSourceReader->ReadSample(
(DWORD)MF_SOURCE_READER_FIRST_VIDEO_STREAM,
0,
&streamIndex,
&dwFlags,
NULL,
&pSampleTmp
);
if (FAILED(hr)) { goto done; }
if (dwFlags & MF_SOURCE_READERF_ENDOFSTREAM)
{
break;
}
if (dwFlags & MF_SOURCE_READERF_CURRENTMEDIATYPECHANGED)
{
// Type change. Get the new format.
//hr = GetVideoFormat(&m_format);
if (FAILED(hr)) { goto done; }
}
if (pSampleTmp == NULL)
{
continue;
}
// We got a sample. Hold onto it.
SafeRelease(&pSample);
pSample = pSampleTmp;
pSample->AddRef();
if (SUCCEEDED( pSample->GetSampleTime(&hnsTimeStamp) ))
{
// Keep going until we get a frame that is within tolerance of the
// desired seek position, or until we skip MAX_FRAMES_TO_SKIP frames.
// During this process, we might reach the end of the file, so we
// always cache the last sample that we got (pSample).
if ( (cSkipped < MAX_FRAMES_TO_SKIP) &&
(hnsTimeStamp + SEEK_TOLERANCE < hnsPos) )
{
SafeRelease(&pSampleTmp);
++cSkipped;
continue;
}
}
SafeRelease(&pSampleTmp);
hnsPos = hnsTimeStamp;
break;
}
if (pSample)
{
CHK(pSample->ConvertToContiguousBuffer(&pBuffer));
CHK(pBuffer->QueryInterface(IID_IMF2DBuffer2, (void**)&pImageBuffer));
hr = pImageBuffer->Lock2DSize(MF2DBuffer_LockFlags_Read, &pBitmapData, &strideSize, &pBufferStart, &bufferLength);
hr = pBufferByteAccess->Buffer(&pBitmapData);
CHK(MFCopyImage(pBitmapData, 0, pBufferStart, strideSize, 1280, 720));
}
else
{
hr = MF_E_END_OF_STREAM;
}
done:
if (pBitmapData)
{
pImageBuffer->Unlock2D();
}
SafeRelease(&pBuffer);
SafeRelease(&pSample);
SafeRelease(&pImageBuffer);
SafeRelease(&pBufferStart);
return bitmap;
});
}
I didn't run your code, it looks similar to how I would do it.
One note though...
As far as I know for gpu acceleration (or at least to have control of your d3d device), the IMFSourceReader needs a IMFDXGIManager initialized (ResetDevice) with a D3D device (with ID3D10Multithread::SetMultithread(TRUE) ). The IMFDXGIManager will be set to your spReaderAttributes with the MF_SOURCE_READER_D3D_MANAGER key.
Also you can get a IMFDXGIBuffer from your sample and render it using a SurfaceImageSource (D3D interop with xaml).
这篇关于未压缩的视频样本（IMFSample / RGB32）到位图缩略图的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
