DirectShow: use supported pixel formats for QCamera video surface

[ChangeLog][DirectShow] Do not convert QCamera video frames to RGB32
if provided QAbstractVideoSurface supports frame pixel format,
requested by QCameraViewfinderSettings.

Task-number: QTBUG-68768
Change-Id: I78d0aaf6c22c4bfee2b17f78a3709d7ba9a8b4fa
Reviewed-by: VaL Doroshchuk <valentyn.doroshchuk@qt.io>

1 files changed, 28 insertions, 25 deletions

diff --git a/src/plugins/directshow/camera/dscamerasession.cpp b/src/plugins/directshow/camera/dscamerasession.cpp
index 43cc9dbd1..73c97c824 100644
--- a/src/plugins/directshow/camera/dscamerasession.cpp
+++ b/src/plugins/directshow/camera/dscamerasession.cpp
@@ -44,6 +44,7 @@
 #include <QtMultimedia/qvideosurfaceformat.h>
 #include <QtMultimedia/qcameraimagecapture.h>
 #include <private/qmemoryvideobuffer_p.h>
+#include <private/qvideoframe_p.h>
 
 #include "dscamerasession.h"
 #include "dsvideorenderer.h"
@@ -67,6 +68,7 @@ DSCameraSession::DSCameraSession(QObject *parent)
     , m_previewStarted(false)
     , m_surface(nullptr)
     , m_previewPixelFormat(QVideoFrame::Format_Invalid)
+    , m_stride(-1)
     , m_readyForCapture(false)
     , m_imageIdCounter(0)
     , m_currentImageId(-1)
@@ -613,12 +615,9 @@ void DSCameraSession::onFrameAvailable(double time, const QByteArray &data)
     // the device might be potentially unplugged.
     m_deviceLostEventTimer.start(100);
 
-    // (We should be getting only RGB32 data)
-    int stride = m_previewSize.width() * 4;
-
     // In case the source produces frames faster than we can display them,
     // only keep the most recent one
-    m_currentFrame = QVideoFrame(new QMemoryVideoBuffer(data, stride),
+    m_currentFrame = QVideoFrame(new QMemoryVideoBuffer(data, m_stride),
                                  m_previewSize,
                                  m_previewPixelFormat);
 
@@ -657,17 +656,11 @@ void DSCameraSession::presentFrame()
     m_captureMutex.lock();
 
     if (m_capturedFrame.isValid()) {
-        Q_ASSERT(m_previewPixelFormat == QVideoFrame::Format_RGB32);
-
-        m_capturedFrame.map(QAbstractVideoBuffer::ReadOnly);
 
-        captureImage = QImage(m_capturedFrame.bits(),
-                                m_previewSize.width(), m_previewSize.height(),
-                                QImage::Format_RGB32);
+        captureImage = qt_imageFromVideoFrame(m_capturedFrame);
 
-        captureImage = captureImage.mirrored(m_needsHorizontalMirroring); // also causes a deep copy of the data
-
-        m_capturedFrame.unmap();
+        const bool needsVerticalMirroring = m_previewSurfaceFormat.scanLineDirection() != QVideoSurfaceFormat::TopToBottom;
+        captureImage = captureImage.mirrored(m_needsHorizontalMirroring, needsVerticalMirroring); // also causes a deep copy of the data
 
         QtConcurrent::run(this, &DSCameraSession::processCapturedImage,
                           m_currentImageId, m_captureDestinations, captureImage, m_imageCaptureFileName);
@@ -878,22 +871,34 @@ bool DSCameraSession::configurePreviewFormat()
     VIDEOINFOHEADER *videoInfo = reinterpret_cast<VIDEOINFOHEADER*>(m_sourceFormat->pbFormat);
     videoInfo->AvgTimePerFrame = 10000000 / resolvedViewfinderSettings.maximumFrameRate();
 
-    // We only support RGB32, if the capture source doesn't support
-    // that format, the graph builder will automatically insert a
-    // converter.
+    m_previewPixelFormat = resolvedViewfinderSettings.pixelFormat();
+    const AM_MEDIA_TYPE *resolvedGrabberFormat = &m_sourceFormat;
 
-    if (m_surface && !m_surface->supportedPixelFormats(QAbstractVideoBuffer::NoHandle)
-            .contains(QVideoFrame::Format_RGB32)) {
-        qWarning() << "Video surface needs to support RGB32 pixel format";
-        return false;
+    if (m_surface) {
+        const auto surfaceFormats = m_surface->supportedPixelFormats(QAbstractVideoBuffer::NoHandle);
+        if (!surfaceFormats.contains(m_previewPixelFormat)) {
+            if (surfaceFormats.contains(QVideoFrame::Format_RGB32)) {
+                // As a fallback, we support RGB32, if the capture source doesn't support
+                // that format, the graph builder will automatically insert a
+                // converter (when possible).
+
+                static const AM_MEDIA_TYPE rgb32GrabberFormat { MEDIATYPE_Video, MEDIASUBTYPE_ARGB32, 0, 0, 0, FORMAT_VideoInfo, nullptr, 0, nullptr};
+                resolvedGrabberFormat = &rgb32GrabberFormat;
+                m_previewPixelFormat = QVideoFrame::Format_RGB32;
+
+            } else {
+                qWarning() << "Video surface needs to support at least RGB32 pixel format";
+                return false;
+            }
+        }
     }
 
-    m_previewPixelFormat = QVideoFrame::Format_RGB32;
     m_previewSize = resolvedViewfinderSettings.resolution();
     m_previewSurfaceFormat = QVideoSurfaceFormat(m_previewSize,
                                                  m_previewPixelFormat,
                                                  QAbstractVideoBuffer::NoHandle);
-    m_previewSurfaceFormat.setScanLineDirection(QVideoSurfaceFormat::BottomToTop);
+    m_previewSurfaceFormat.setScanLineDirection(DirectShowMediaType::scanLineDirection(m_previewPixelFormat, videoInfo->bmiHeader));
+    m_stride = DirectShowMediaType::bytesPerLine(m_previewSurfaceFormat);
 
     HRESULT hr;
     IAMStreamConfig* pConfig = 0;
@@ -914,9 +919,7 @@ bool DSCameraSession::configurePreviewFormat()
         return false;
     }
 
-    // Set sample grabber format
-    static const AM_MEDIA_TYPE grabberFormat { MEDIATYPE_Video, MEDIASUBTYPE_ARGB32, 0, 0, 0, FORMAT_VideoInfo, nullptr, 0, nullptr};
-    if (!m_previewSampleGrabber->setMediaType(&grabberFormat))
+    if (!m_previewSampleGrabber->setMediaType(resolvedGrabberFormat))
         return false;
 
     m_previewSampleGrabber->start(DirectShowSampleGrabber::CallbackMethod::BufferCB);