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[cscore] Use Lock2DSize if possible for Windows USB cameras (#3326)

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Can remove a memory copy in many cases. This also fixes a bug where any mjpeg cameras on windows wouldn't work if the fast path was taken.
This commit is contained in:
Thad House
2021-05-01 07:07:37 -07:00
committed by GitHub
parent 5127380727
commit 6b50323b07
1 changed files with 33 additions and 19 deletions
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52
cscore/src/main/native/windows/UsbCameraImpl.cpp
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@@ -293,32 +293,45 @@ void UsbCameraImpl::ProcessFrame(IMFSample* videoSample,
return;
}
bool lock2d = false;
BYTE* ptr = NULL;
LONG pitch = 0;
DWORD maxsize = 0, cursize = 0;
DWORD length = 0;
// "For 2-D buffers, the Lock2D method is more efficient than the Lock
// method" see IMFMediaBuffer::Lock method documentation:
// https://msdn.microsoft.com/en-us/library/windows/desktop/bb970366(v=vs.85).aspx
ComPtr<IMF2DBuffer> buffer2d;
DWORD memLength2d = 0;
if (true) {
buffer2d = buf.As<IMF2DBuffer>();
if (buffer2d) {
buffer2d->GetContiguousLength(&memLength2d);
if (SUCCEEDED(buffer2d->Lock2D(&ptr, &pitch))) {
lock2d = true;
// First try to access using Lock2DSize, then try Lock2D, then fallback
// https://docs.microsoft.com/en-us/windows/win32/api/mfobjects/nf-mfobjects-imfmediabuffer-lock
ComPtr<IMF2DBuffer> buffer2d = buf.As<IMF2DBuffer>();
if (buffer2d) {
BYTE* scanline0 = nullptr;
HRESULT result;
ComPtr<IMF2DBuffer2> buffer2d2 = buf.As<IMF2DBuffer2>();
if (buffer2d2) {
BYTE* datastart;
result = buffer2d2->Lock2DSize(MF2DBuffer_LockFlags_Read, &scanline0,
&pitch, &datastart, &length);
} else {
result = buffer2d->Lock2D(&scanline0, &pitch);
}
if (SUCCEEDED(result)) {
BOOL isContiguous;
if (pitch > 0 && SUCCEEDED(buffer2d->IsContiguousFormat(&isContiguous)) &&
isContiguous &&
(length || SUCCEEDED(buffer2d->GetContiguousLength(&length)))) {
// Use the buffer pointer.
ptr = scanline0;
} else {
// Release the buffer and fall back to Lock().
buffer2d->Unlock2D();
}
}
}
if (ptr == NULL) {
if (!SUCCEEDED(buf->Lock(&ptr, &maxsize, &cursize))) {
buffer2d = nullptr;
DWORD maxsize = 0;
if (!SUCCEEDED(buf->Lock(&ptr, &maxsize, &length))) {
return;
}
}
if (!ptr)
return;
cv::Mat tmpMat;
std::unique_ptr<Image> dest;
@@ -328,7 +341,7 @@ void UsbCameraImpl::ProcessFrame(IMFSample* videoSample,
case cs::VideoMode::PixelFormat::kMJPEG: {
// Special case
PutFrame(VideoMode::kMJPEG, mode.width, mode.height,
wpi::StringRef(reinterpret_cast<char*>(ptr), cursize),
wpi::StringRef(reinterpret_cast<char*>(ptr), length),
wpi::Now());
doFinalSet = false;
break;
@@ -360,10 +373,11 @@ void UsbCameraImpl::ProcessFrame(IMFSample* videoSample,
PutFrame(std::move(dest), wpi::Now());
}
if (lock2d)
if (buffer2d) {
buffer2d->Unlock2D();
else
} else {
buf->Unlock();
}
}
LRESULT UsbCameraImpl::PumpMain(HWND hwnd, UINT uiMsg, WPARAM wParam,