如何将 Graphics Capture API 连接到 IMFSinkWriter
How do I connect the Graphics Capture API to IMFSinkWriter
我正在尝试编写一些代码,将 Windows::Graphics::Capture
API 连接到 IMFSinkWriter
以便将桌面捕获到 MP4 文件。我发现 IMFSinkWriter
WriteSample
函数总是 returns 0x80070057,我正在尝试理解原因。我怀疑有一个明显的错误,因为我对 COM、WinRT、DirectX 等不是很熟悉。有什么想法吗?
#include <iostream>
#include <Windows.h>
// XXX workaround bug in platform headers where this has a circular declaration
#include "winrt/base.h"
namespace winrt::impl
{
template <typename Async>
auto wait_for(Async const& async, Windows::Foundation::TimeSpan const& timeout);
}
// XXX
#include <dxgi.h>
#include <inspectable.h>
#include <dxgi1_2.h>
#include <d3d11.h>
#include <mfapi.h>
#include <mfidl.h>
#include <mfreadwrite.h>
#include <codecapi.h>
#include <strmif.h>
#include <winrt/Windows.Foundation.h>
#include <winrt/Windows.System.h>
#include <winrt/Windows.Graphics.Capture.h>
#include <windows.graphics.capture.interop.h>
#include <windows.graphics.directx.direct3d11.interop.h>
#pragma comment(lib, "Mfuuid.lib")
#pragma comment(lib, "Mfplat.lib")
#pragma comment(lib, "mfreadwrite.lib")
#pragma comment(lib, "Mf.lib")
winrt::com_ptr<IMFSinkWriter> sinkWriter;
std::chrono::steady_clock::time_point firstFrameTime;
std::chrono::steady_clock::time_point lastFrameTime;
bool recordedFirstFrame = false;
void OnFrameArrived(winrt::Windows::Graphics::Capture::Direct3D11CaptureFramePool const& sender, winrt::Windows::Foundation::IInspectable const &) {
winrt::Windows::Graphics::Capture::Direct3D11CaptureFrame frame = sender.TryGetNextFrame();
std::chrono::steady_clock::time_point frameTime = std::chrono::steady_clock::now();
LONGLONG duration = 0;
LONGLONG frametime100ns;
if (!recordedFirstFrame) {
recordedFirstFrame = true;
firstFrameTime = frameTime;
frametime100ns = 0;
}
else {
frametime100ns = std::chrono::duration_cast<std::chrono::nanoseconds>(std::chrono::steady_clock::now() - firstFrameTime).count() / 100;
duration = std::chrono::duration_cast<std::chrono::milliseconds>(frameTime - lastFrameTime).count();
}
auto surface = frame.Surface();
auto access = surface.as<Windows::Graphics::DirectX::Direct3D11::IDirect3DDxgiInterfaceAccess>();
winrt::com_ptr<ID3D11Texture2D> texture;
winrt::check_hresult(access->GetInterface(winrt::guid_of<ID3D11Texture2D>(), texture.put_void()));
IMFMediaBuffer* buffer;
MFCreateDXGISurfaceBuffer(__uuidof(ID3D11Texture2D), texture.get(), 0, FALSE, &buffer);
IMFSample *sample;
winrt::check_hresult(MFCreateSample(&sample));
HRESULT hr = sample->AddBuffer(buffer);
printf("add buffer! %x\n", hr);
hr = sample->SetSampleTime(frametime100ns);
printf("set sample time (%lld) %d\n", frametime100ns, hr);
hr = sample->SetSampleDuration(duration);
printf("set sample duration (%lld) %d\n", duration, hr);
hr = sinkWriter->WriteSample(0 /* video stream index */, sample);
printf("wrote sample %x\n", hr);
lastFrameTime = frameTime;
}
int main()
{
winrt::init_apartment(winrt::apartment_type::multi_threaded);
winrt::check_hresult(MFStartup(MF_VERSION, MFSTARTUP_NOSOCKET));
// get a list of monitor handles
std::vector<HMONITOR> monitors;
EnumDisplayMonitors(
nullptr, nullptr,
[](HMONITOR hmon, HDC, LPRECT, LPARAM lparam) {
auto& monitors = *reinterpret_cast<std::vector<HMONITOR>*>(lparam);
monitors.push_back(hmon);
return TRUE;
},
reinterpret_cast<LPARAM>(&monitors)
);
//get GraphicsCaptureItem for first monitor
auto interop_factory = winrt::get_activation_factory<winrt::Windows::Graphics::Capture::GraphicsCaptureItem, IGraphicsCaptureItemInterop>();
winrt::Windows::Graphics::Capture::GraphicsCaptureItem item = { nullptr };
winrt::check_hresult(
interop_factory->CreateForMonitor(
monitors[0],
winrt::guid_of<ABI::Windows::Graphics::Capture::IGraphicsCaptureItem>(),
winrt::put_abi(item)
)
);
// Create Direct 3D Device
winrt::com_ptr<ID3D11Device> d3dDevice;
winrt::check_hresult(D3D11CreateDevice(nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, D3D11_CREATE_DEVICE_BGRA_SUPPORT,
nullptr, 0, D3D11_SDK_VERSION, d3dDevice.put(), nullptr, nullptr));
winrt::Windows::Graphics::DirectX::Direct3D11::IDirect3DDevice device;
const auto dxgiDevice = d3dDevice.as<IDXGIDevice>();
{
winrt::com_ptr<::IInspectable> inspectable;
winrt::check_hresult(CreateDirect3D11DeviceFromDXGIDevice(dxgiDevice.get(), inspectable.put()));
device = inspectable.as<winrt::Windows::Graphics::DirectX::Direct3D11::IDirect3DDevice>();
}
auto idxgiDevice2 = dxgiDevice.as<IDXGIDevice2>();
winrt::com_ptr<IDXGIAdapter> adapter;
winrt::check_hresult(idxgiDevice2->GetParent(winrt::guid_of<IDXGIAdapter>(), adapter.put_void()));
winrt::com_ptr<IDXGIFactory2> factory;
winrt::check_hresult(adapter->GetParent(winrt::guid_of<IDXGIFactory2>(), factory.put_void()));
ID3D11DeviceContext* d3dContext = nullptr;
d3dDevice->GetImmediateContext(&d3dContext);
// setup swap chain
DXGI_SWAP_CHAIN_DESC1 desc = {};
desc.Width = static_cast<uint32_t>(item.Size().Width);
desc.Height = static_cast<uint32_t>(item.Size().Height);
desc.Format = static_cast<DXGI_FORMAT>(winrt::Windows::Graphics::DirectX::DirectXPixelFormat::R16G16B16A16Float);
desc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
desc.SampleDesc.Count = 1;
desc.SampleDesc.Quality = 0;
desc.BufferCount = 2;
desc.Scaling = DXGI_SCALING_STRETCH;
desc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL;
desc.AlphaMode = DXGI_ALPHA_MODE_PREMULTIPLIED;
winrt::com_ptr<IDXGISwapChain1> swapchain;
winrt::check_hresult(factory->CreateSwapChainForComposition(d3dDevice.get(), &desc, nullptr, swapchain.put()));
auto framepool = winrt::Windows::Graphics::Capture::Direct3D11CaptureFramePool::CreateFreeThreaded(device, winrt::Windows::Graphics::DirectX::DirectXPixelFormat::R16G16B16A16Float, 2, item.Size());
auto session = framepool.CreateCaptureSession(item);
framepool.FrameArrived(OnFrameArrived);
//Setup MF output stream
winrt::com_ptr<IMFDXGIDeviceManager> devManager;
UINT resetToken;
winrt::check_hresult(MFCreateDXGIDeviceManager(&resetToken, devManager.put()));
winrt::check_hresult(devManager->ResetDevice(d3dDevice.get(), resetToken));
winrt::com_ptr<IMFByteStream> outputStream;
winrt::check_hresult(MFCreateFile(MF_ACCESSMODE_READWRITE, MF_OPENMODE_DELETE_IF_EXIST, MF_FILEFLAGS_NONE, L"C:\test.mp4", outputStream.put()));
//configure MF output media type
winrt::com_ptr<IMFMediaType> videoMediaType;
//winrt::com_ptr<IMFMediaType> audioMediaType;
//for video
winrt::check_hresult(MFCreateMediaType(videoMediaType.put()));
winrt::check_hresult(videoMediaType->SetGUID(MF_MT_MAJOR_TYPE, MFMediaType_Video));
winrt::check_hresult(videoMediaType->SetGUID(MF_MT_SUBTYPE, MFVideoFormat_H264));
winrt::check_hresult(videoMediaType->SetUINT32(MF_MT_AVG_BITRATE, 2000000));
winrt::check_hresult(videoMediaType->SetUINT32(MF_MT_INTERLACE_MODE, MFVideoInterlace_Progressive));
winrt::check_hresult(videoMediaType->SetUINT32(MF_MT_MPEG2_PROFILE, eAVEncH264VProfile_Main));
winrt::check_hresult(videoMediaType->SetUINT32(MF_MT_YUV_MATRIX, MFVideoTransferMatrix_BT601));
winrt::check_hresult(MFSetAttributeSize(videoMediaType.get(), MF_MT_FRAME_SIZE, item.Size().Width, item.Size().Height));
winrt::check_hresult(MFSetAttributeRatio(videoMediaType.get(), MF_MT_FRAME_RATE, 30, 1));
winrt::check_hresult(MFSetAttributeRatio(videoMediaType.get(), MF_MT_PIXEL_ASPECT_RATIO, 1, 1));
//Creates a streaming writer
winrt::com_ptr<IMFMediaSink> mp4StreamSink;
winrt::check_hresult(MFCreateMPEG4MediaSink(outputStream.get(), videoMediaType.get(), NULL, mp4StreamSink.put()));
//setup MF Input stream
winrt::com_ptr<IMFMediaType> inputVideoMediaType;
HRESULT hr = S_OK;
GUID majortype = { 0 };
MFRatio par = { 0 };
hr = videoMediaType->GetMajorType(&majortype);
if (majortype != MFMediaType_Video)
{
throw new winrt::hresult_invalid_argument();
}
// Create a new media type and copy over all of the items.
// This ensures that extended color information is retained.
winrt::check_hresult(MFCreateMediaType(inputVideoMediaType.put()));
winrt::check_hresult(videoMediaType->CopyAllItems(inputVideoMediaType.get()));
// Set the subtype.
winrt::check_hresult(inputVideoMediaType->SetGUID(MF_MT_SUBTYPE, MFVideoFormat_ARGB32));
// Uncompressed means all samples are independent.
winrt::check_hresult(inputVideoMediaType->SetUINT32(MF_MT_ALL_SAMPLES_INDEPENDENT, TRUE));
// Fix up PAR if not set on the original type.
hr = MFGetAttributeRatio(
inputVideoMediaType.get(),
MF_MT_PIXEL_ASPECT_RATIO,
(UINT32*)&par.Numerator,
(UINT32*)&par.Denominator
);
// Default to square pixels.
if (FAILED(hr))
{
winrt::check_hresult(MFSetAttributeRatio(
inputVideoMediaType.get(),
MF_MT_PIXEL_ASPECT_RATIO,
1, 1
));
}
winrt::check_hresult(MFSetAttributeSize(inputVideoMediaType.get(), MF_MT_FRAME_SIZE, item.Size().Width, item.Size().Height));
inputVideoMediaType->SetUINT32(MF_MT_VIDEO_ROTATION, MFVideoRotationFormat_0); //XXX where do we get the rotation from?
winrt::com_ptr<IMFAttributes> attributes;
winrt::check_hresult(MFCreateAttributes(attributes.put(), 6));
winrt::check_hresult(attributes->SetGUID(MF_TRANSCODE_CONTAINERTYPE, MFTranscodeContainerType_MPEG4));
winrt::check_hresult(attributes->SetUINT32(MF_READWRITE_ENABLE_HARDWARE_TRANSFORMS, 1));
winrt::check_hresult(attributes->SetUINT32(MF_MPEG4SINK_MOOV_BEFORE_MDAT, 1));
winrt::check_hresult(attributes->SetUINT32(MF_LOW_LATENCY, FALSE)); ///XXX should we?
winrt::check_hresult(attributes->SetUINT32(MF_SINK_WRITER_DISABLE_THROTTLING, FALSE)); //XX shuold we?
// Add device manager to attributes. This enables hardware encoding.
winrt::check_hresult(attributes->SetUnknown(MF_SINK_WRITER_D3D_MANAGER, devManager.get()));
//winrt::com_ptr<IMFSinkWriter> sinkWriter;
winrt::check_hresult(MFCreateSinkWriterFromMediaSink(mp4StreamSink.get(), attributes.get(), sinkWriter.put()));
sinkWriter->SetInputMediaType(0, inputVideoMediaType.get(), nullptr);
winrt::com_ptr<ICodecAPI> encoder;
sinkWriter->GetServiceForStream(0 /* video stream index */, GUID_NULL, IID_PPV_ARGS(encoder.put()));
VARIANT var;
VariantInit(&var);
var.vt = VT_UI4;
var.ulVal = eAVEncCommonRateControlMode_Quality;
winrt::check_hresult(encoder->SetValue(&CODECAPI_AVEncCommonRateControlMode, &var));
var.ulVal = 70;
winrt::check_hresult(encoder->SetValue(&CODECAPI_AVEncCommonQuality, &var));
winrt::check_hresult(sinkWriter->BeginWriting());
session.StartCapture();
std::cout << "Hello World!\n";
Sleep(1000);
session.Close();
sinkWriter->Flush(0);
sinkWriter->Finalize();
}
我能够找到问题所在。上面的代码有两个问题:
- 需要对 IMFMediaBuffer 对象调用
SetCurrentLength()
。这看起来很愚蠢,因为获取长度的方法是从 IMFMediaBuffer 对象获取 IMF2DBuffer 接口并调用 GetContiguousLength()
,但它有效。
- 直接从
OnFrameArrived()
回调中获取纹理并将其传递到 IMF 接收器也是错误的。这将耗尽帧池(声明为具有 2 个帧)并挂起编码器。一种可能的解决方案是在将数据传递给编码器之前将其复制到新纹理中。
我正在尝试编写一些代码,将 Windows::Graphics::Capture
API 连接到 IMFSinkWriter
以便将桌面捕获到 MP4 文件。我发现 IMFSinkWriter
WriteSample
函数总是 returns 0x80070057,我正在尝试理解原因。我怀疑有一个明显的错误,因为我对 COM、WinRT、DirectX 等不是很熟悉。有什么想法吗?
#include <iostream>
#include <Windows.h>
// XXX workaround bug in platform headers where this has a circular declaration
#include "winrt/base.h"
namespace winrt::impl
{
template <typename Async>
auto wait_for(Async const& async, Windows::Foundation::TimeSpan const& timeout);
}
// XXX
#include <dxgi.h>
#include <inspectable.h>
#include <dxgi1_2.h>
#include <d3d11.h>
#include <mfapi.h>
#include <mfidl.h>
#include <mfreadwrite.h>
#include <codecapi.h>
#include <strmif.h>
#include <winrt/Windows.Foundation.h>
#include <winrt/Windows.System.h>
#include <winrt/Windows.Graphics.Capture.h>
#include <windows.graphics.capture.interop.h>
#include <windows.graphics.directx.direct3d11.interop.h>
#pragma comment(lib, "Mfuuid.lib")
#pragma comment(lib, "Mfplat.lib")
#pragma comment(lib, "mfreadwrite.lib")
#pragma comment(lib, "Mf.lib")
winrt::com_ptr<IMFSinkWriter> sinkWriter;
std::chrono::steady_clock::time_point firstFrameTime;
std::chrono::steady_clock::time_point lastFrameTime;
bool recordedFirstFrame = false;
void OnFrameArrived(winrt::Windows::Graphics::Capture::Direct3D11CaptureFramePool const& sender, winrt::Windows::Foundation::IInspectable const &) {
winrt::Windows::Graphics::Capture::Direct3D11CaptureFrame frame = sender.TryGetNextFrame();
std::chrono::steady_clock::time_point frameTime = std::chrono::steady_clock::now();
LONGLONG duration = 0;
LONGLONG frametime100ns;
if (!recordedFirstFrame) {
recordedFirstFrame = true;
firstFrameTime = frameTime;
frametime100ns = 0;
}
else {
frametime100ns = std::chrono::duration_cast<std::chrono::nanoseconds>(std::chrono::steady_clock::now() - firstFrameTime).count() / 100;
duration = std::chrono::duration_cast<std::chrono::milliseconds>(frameTime - lastFrameTime).count();
}
auto surface = frame.Surface();
auto access = surface.as<Windows::Graphics::DirectX::Direct3D11::IDirect3DDxgiInterfaceAccess>();
winrt::com_ptr<ID3D11Texture2D> texture;
winrt::check_hresult(access->GetInterface(winrt::guid_of<ID3D11Texture2D>(), texture.put_void()));
IMFMediaBuffer* buffer;
MFCreateDXGISurfaceBuffer(__uuidof(ID3D11Texture2D), texture.get(), 0, FALSE, &buffer);
IMFSample *sample;
winrt::check_hresult(MFCreateSample(&sample));
HRESULT hr = sample->AddBuffer(buffer);
printf("add buffer! %x\n", hr);
hr = sample->SetSampleTime(frametime100ns);
printf("set sample time (%lld) %d\n", frametime100ns, hr);
hr = sample->SetSampleDuration(duration);
printf("set sample duration (%lld) %d\n", duration, hr);
hr = sinkWriter->WriteSample(0 /* video stream index */, sample);
printf("wrote sample %x\n", hr);
lastFrameTime = frameTime;
}
int main()
{
winrt::init_apartment(winrt::apartment_type::multi_threaded);
winrt::check_hresult(MFStartup(MF_VERSION, MFSTARTUP_NOSOCKET));
// get a list of monitor handles
std::vector<HMONITOR> monitors;
EnumDisplayMonitors(
nullptr, nullptr,
[](HMONITOR hmon, HDC, LPRECT, LPARAM lparam) {
auto& monitors = *reinterpret_cast<std::vector<HMONITOR>*>(lparam);
monitors.push_back(hmon);
return TRUE;
},
reinterpret_cast<LPARAM>(&monitors)
);
//get GraphicsCaptureItem for first monitor
auto interop_factory = winrt::get_activation_factory<winrt::Windows::Graphics::Capture::GraphicsCaptureItem, IGraphicsCaptureItemInterop>();
winrt::Windows::Graphics::Capture::GraphicsCaptureItem item = { nullptr };
winrt::check_hresult(
interop_factory->CreateForMonitor(
monitors[0],
winrt::guid_of<ABI::Windows::Graphics::Capture::IGraphicsCaptureItem>(),
winrt::put_abi(item)
)
);
// Create Direct 3D Device
winrt::com_ptr<ID3D11Device> d3dDevice;
winrt::check_hresult(D3D11CreateDevice(nullptr, D3D_DRIVER_TYPE_HARDWARE, nullptr, D3D11_CREATE_DEVICE_BGRA_SUPPORT,
nullptr, 0, D3D11_SDK_VERSION, d3dDevice.put(), nullptr, nullptr));
winrt::Windows::Graphics::DirectX::Direct3D11::IDirect3DDevice device;
const auto dxgiDevice = d3dDevice.as<IDXGIDevice>();
{
winrt::com_ptr<::IInspectable> inspectable;
winrt::check_hresult(CreateDirect3D11DeviceFromDXGIDevice(dxgiDevice.get(), inspectable.put()));
device = inspectable.as<winrt::Windows::Graphics::DirectX::Direct3D11::IDirect3DDevice>();
}
auto idxgiDevice2 = dxgiDevice.as<IDXGIDevice2>();
winrt::com_ptr<IDXGIAdapter> adapter;
winrt::check_hresult(idxgiDevice2->GetParent(winrt::guid_of<IDXGIAdapter>(), adapter.put_void()));
winrt::com_ptr<IDXGIFactory2> factory;
winrt::check_hresult(adapter->GetParent(winrt::guid_of<IDXGIFactory2>(), factory.put_void()));
ID3D11DeviceContext* d3dContext = nullptr;
d3dDevice->GetImmediateContext(&d3dContext);
// setup swap chain
DXGI_SWAP_CHAIN_DESC1 desc = {};
desc.Width = static_cast<uint32_t>(item.Size().Width);
desc.Height = static_cast<uint32_t>(item.Size().Height);
desc.Format = static_cast<DXGI_FORMAT>(winrt::Windows::Graphics::DirectX::DirectXPixelFormat::R16G16B16A16Float);
desc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
desc.SampleDesc.Count = 1;
desc.SampleDesc.Quality = 0;
desc.BufferCount = 2;
desc.Scaling = DXGI_SCALING_STRETCH;
desc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL;
desc.AlphaMode = DXGI_ALPHA_MODE_PREMULTIPLIED;
winrt::com_ptr<IDXGISwapChain1> swapchain;
winrt::check_hresult(factory->CreateSwapChainForComposition(d3dDevice.get(), &desc, nullptr, swapchain.put()));
auto framepool = winrt::Windows::Graphics::Capture::Direct3D11CaptureFramePool::CreateFreeThreaded(device, winrt::Windows::Graphics::DirectX::DirectXPixelFormat::R16G16B16A16Float, 2, item.Size());
auto session = framepool.CreateCaptureSession(item);
framepool.FrameArrived(OnFrameArrived);
//Setup MF output stream
winrt::com_ptr<IMFDXGIDeviceManager> devManager;
UINT resetToken;
winrt::check_hresult(MFCreateDXGIDeviceManager(&resetToken, devManager.put()));
winrt::check_hresult(devManager->ResetDevice(d3dDevice.get(), resetToken));
winrt::com_ptr<IMFByteStream> outputStream;
winrt::check_hresult(MFCreateFile(MF_ACCESSMODE_READWRITE, MF_OPENMODE_DELETE_IF_EXIST, MF_FILEFLAGS_NONE, L"C:\test.mp4", outputStream.put()));
//configure MF output media type
winrt::com_ptr<IMFMediaType> videoMediaType;
//winrt::com_ptr<IMFMediaType> audioMediaType;
//for video
winrt::check_hresult(MFCreateMediaType(videoMediaType.put()));
winrt::check_hresult(videoMediaType->SetGUID(MF_MT_MAJOR_TYPE, MFMediaType_Video));
winrt::check_hresult(videoMediaType->SetGUID(MF_MT_SUBTYPE, MFVideoFormat_H264));
winrt::check_hresult(videoMediaType->SetUINT32(MF_MT_AVG_BITRATE, 2000000));
winrt::check_hresult(videoMediaType->SetUINT32(MF_MT_INTERLACE_MODE, MFVideoInterlace_Progressive));
winrt::check_hresult(videoMediaType->SetUINT32(MF_MT_MPEG2_PROFILE, eAVEncH264VProfile_Main));
winrt::check_hresult(videoMediaType->SetUINT32(MF_MT_YUV_MATRIX, MFVideoTransferMatrix_BT601));
winrt::check_hresult(MFSetAttributeSize(videoMediaType.get(), MF_MT_FRAME_SIZE, item.Size().Width, item.Size().Height));
winrt::check_hresult(MFSetAttributeRatio(videoMediaType.get(), MF_MT_FRAME_RATE, 30, 1));
winrt::check_hresult(MFSetAttributeRatio(videoMediaType.get(), MF_MT_PIXEL_ASPECT_RATIO, 1, 1));
//Creates a streaming writer
winrt::com_ptr<IMFMediaSink> mp4StreamSink;
winrt::check_hresult(MFCreateMPEG4MediaSink(outputStream.get(), videoMediaType.get(), NULL, mp4StreamSink.put()));
//setup MF Input stream
winrt::com_ptr<IMFMediaType> inputVideoMediaType;
HRESULT hr = S_OK;
GUID majortype = { 0 };
MFRatio par = { 0 };
hr = videoMediaType->GetMajorType(&majortype);
if (majortype != MFMediaType_Video)
{
throw new winrt::hresult_invalid_argument();
}
// Create a new media type and copy over all of the items.
// This ensures that extended color information is retained.
winrt::check_hresult(MFCreateMediaType(inputVideoMediaType.put()));
winrt::check_hresult(videoMediaType->CopyAllItems(inputVideoMediaType.get()));
// Set the subtype.
winrt::check_hresult(inputVideoMediaType->SetGUID(MF_MT_SUBTYPE, MFVideoFormat_ARGB32));
// Uncompressed means all samples are independent.
winrt::check_hresult(inputVideoMediaType->SetUINT32(MF_MT_ALL_SAMPLES_INDEPENDENT, TRUE));
// Fix up PAR if not set on the original type.
hr = MFGetAttributeRatio(
inputVideoMediaType.get(),
MF_MT_PIXEL_ASPECT_RATIO,
(UINT32*)&par.Numerator,
(UINT32*)&par.Denominator
);
// Default to square pixels.
if (FAILED(hr))
{
winrt::check_hresult(MFSetAttributeRatio(
inputVideoMediaType.get(),
MF_MT_PIXEL_ASPECT_RATIO,
1, 1
));
}
winrt::check_hresult(MFSetAttributeSize(inputVideoMediaType.get(), MF_MT_FRAME_SIZE, item.Size().Width, item.Size().Height));
inputVideoMediaType->SetUINT32(MF_MT_VIDEO_ROTATION, MFVideoRotationFormat_0); //XXX where do we get the rotation from?
winrt::com_ptr<IMFAttributes> attributes;
winrt::check_hresult(MFCreateAttributes(attributes.put(), 6));
winrt::check_hresult(attributes->SetGUID(MF_TRANSCODE_CONTAINERTYPE, MFTranscodeContainerType_MPEG4));
winrt::check_hresult(attributes->SetUINT32(MF_READWRITE_ENABLE_HARDWARE_TRANSFORMS, 1));
winrt::check_hresult(attributes->SetUINT32(MF_MPEG4SINK_MOOV_BEFORE_MDAT, 1));
winrt::check_hresult(attributes->SetUINT32(MF_LOW_LATENCY, FALSE)); ///XXX should we?
winrt::check_hresult(attributes->SetUINT32(MF_SINK_WRITER_DISABLE_THROTTLING, FALSE)); //XX shuold we?
// Add device manager to attributes. This enables hardware encoding.
winrt::check_hresult(attributes->SetUnknown(MF_SINK_WRITER_D3D_MANAGER, devManager.get()));
//winrt::com_ptr<IMFSinkWriter> sinkWriter;
winrt::check_hresult(MFCreateSinkWriterFromMediaSink(mp4StreamSink.get(), attributes.get(), sinkWriter.put()));
sinkWriter->SetInputMediaType(0, inputVideoMediaType.get(), nullptr);
winrt::com_ptr<ICodecAPI> encoder;
sinkWriter->GetServiceForStream(0 /* video stream index */, GUID_NULL, IID_PPV_ARGS(encoder.put()));
VARIANT var;
VariantInit(&var);
var.vt = VT_UI4;
var.ulVal = eAVEncCommonRateControlMode_Quality;
winrt::check_hresult(encoder->SetValue(&CODECAPI_AVEncCommonRateControlMode, &var));
var.ulVal = 70;
winrt::check_hresult(encoder->SetValue(&CODECAPI_AVEncCommonQuality, &var));
winrt::check_hresult(sinkWriter->BeginWriting());
session.StartCapture();
std::cout << "Hello World!\n";
Sleep(1000);
session.Close();
sinkWriter->Flush(0);
sinkWriter->Finalize();
}
我能够找到问题所在。上面的代码有两个问题:
- 需要对 IMFMediaBuffer 对象调用
SetCurrentLength()
。这看起来很愚蠢,因为获取长度的方法是从 IMFMediaBuffer 对象获取 IMF2DBuffer 接口并调用GetContiguousLength()
,但它有效。 - 直接从
OnFrameArrived()
回调中获取纹理并将其传递到 IMF 接收器也是错误的。这将耗尽帧池(声明为具有 2 个帧)并挂起编码器。一种可能的解决方案是在将数据传递给编码器之前将其复制到新纹理中。