Add resolution and fps on mfw_v4lsrc

Add support for changing resolution and frame rate with mfw_v4lsrc.
This is essential for embedded applications that are not happy with
the default VGA@30.

This makes constructs like the following functional on devices like
i.MX6 with MIPI cameras:

Camera { viewfinder { resolution: "320x240"; maximumFrameRate: 15 } }

Change-Id: Ia297afdb5ca51c6e55ad45dce37fdab7da3a5cfb
Reviewed-by: Yoann Lopes <yoann.lopes@theqtcompany.com>

src/plugins/gstreamer/camerabin/camerabinsession.cpp

@@ -338,6 +338,17 @@ void CameraBinSession::setupCaptureResolution()
         g_object_set(m_camerabin, VIDEO_CAPTURE_CAPS_PROPERTY, NULL, NULL);
     }
 
+    GstElement *mfw_v4lsrc = 0;
+    if (g_object_class_find_property(G_OBJECT_GET_CLASS(m_videoSrc), "video-source")) {
+        GstElement *videoSrc = 0;
+        g_object_get(G_OBJECT(m_videoSrc), "video-source", &videoSrc, NULL);
+        if (videoSrc) {
+            const char *name = gst_plugin_feature_get_name(GST_PLUGIN_FEATURE(gst_element_get_factory(videoSrc)));
+            if (!qstrcmp(name, "mfw_v4lsrc"))
+                mfw_v4lsrc = videoSrc;
+        }
+    }
+
     resolution = m_viewfinderSettingsControl->resolution();
     if (!resolution.isEmpty()) {
         GstCaps *caps = resolutionToCaps(resolution);
@@ -346,10 +357,35 @@ void CameraBinSession::setupCaptureResolution()
 #endif
         g_object_set(m_camerabin, VIEWFINDER_CAPS_PROPERTY, caps, NULL);
         gst_caps_unref(caps);
+
+        if (mfw_v4lsrc) {
+            int capMode = 0;
+            if (resolution == QSize(320, 240))
+                capMode = 1;
+            else if (resolution == QSize(720, 480))
+                capMode = 2;
+            else if (resolution == QSize(720, 576))
+                capMode = 3;
+            else if (resolution == QSize(1280, 720))
+                capMode = 4;
+            else if (resolution == QSize(1920, 1080))
+                capMode = 5;
+            g_object_set(G_OBJECT(mfw_v4lsrc), "capture-mode", capMode, NULL);
+        }
     } else {
         g_object_set(m_camerabin, VIEWFINDER_CAPS_PROPERTY, NULL, NULL);
     }
 
+    const qreal maxFps = m_viewfinderSettingsControl->maximumFrameRate();
+    if (!qFuzzyIsNull(maxFps)) {
+        if (mfw_v4lsrc) {
+            int n, d;
+            gst_util_double_to_fraction(maxFps, &n, &d);
+            g_object_set(G_OBJECT(mfw_v4lsrc), "fps-n", n, NULL);
+            g_object_set(G_OBJECT(mfw_v4lsrc), "fps-d", d, NULL);
+        }
+    }
+
     if (m_videoEncoder)
         m_videoEncodeControl->applySettings(m_videoEncoder);
 }

src/plugins/gstreamer/camerabin/camerabinviewfindersettings.cpp

@@ -38,7 +38,9 @@
 QT_BEGIN_NAMESPACE
 
 CameraBinViewfinderSettings::CameraBinViewfinderSettings(QObject *parent)
-    : QCameraViewfinderSettingsControl(parent)
+    : QCameraViewfinderSettingsControl(parent),
+      m_minimumFrameRate(0),
+      m_maximumFrameRate(0)
 {
 }
 
@@ -50,10 +52,10 @@ bool CameraBinViewfinderSettings::isViewfinderParameterSupported(ViewfinderParam
 {
     switch (parameter) {
     case Resolution:
-        return true;
-    case PixelAspectRatio:
     case MinimumFrameRate:
     case MaximumFrameRate:
+        return true;
+    case PixelAspectRatio:
     case PixelFormat:
     case UserParameter:
         return false;
@@ -66,9 +68,11 @@ QVariant CameraBinViewfinderSettings::viewfinderParameter(ViewfinderParameter pa
     switch (parameter) {
     case Resolution:
         return m_resolution;
-    case PixelAspectRatio:
     case MinimumFrameRate:
+        return m_minimumFrameRate;
     case MaximumFrameRate:
+        return m_maximumFrameRate;
+    case PixelAspectRatio:
     case PixelFormat:
     case UserParameter:
         return QVariant();
@@ -82,9 +86,13 @@ void CameraBinViewfinderSettings::setViewfinderParameter(ViewfinderParameter par
     case Resolution:
         m_resolution = value.toSize();
         break;
-    case PixelAspectRatio:
     case MinimumFrameRate:
+        m_minimumFrameRate = value.toFloat();
+        break;
     case MaximumFrameRate:
+        m_maximumFrameRate = value.toFloat();
+        break;
+    case PixelAspectRatio:
     case PixelFormat:
     case UserParameter:
         break;
@@ -96,4 +104,14 @@ QSize CameraBinViewfinderSettings::resolution() const
     return m_resolution;
 }
 
+qreal CameraBinViewfinderSettings::minimumFrameRate() const
+{
+    return m_minimumFrameRate;
+}
+
+qreal CameraBinViewfinderSettings::maximumFrameRate() const
+{
+    return m_maximumFrameRate;
+}
+
 QT_END_NAMESPACE

src/plugins/gstreamer/camerabin/camerabinviewfindersettings.h

@@ -52,9 +52,13 @@ public:
     void setViewfinderParameter(ViewfinderParameter parameter, const QVariant &value);
 
     QSize resolution() const;
+    qreal minimumFrameRate() const;
+    qreal maximumFrameRate() const;
 
 private:
     QSize m_resolution;
+    qreal m_minimumFrameRate;
+    qreal m_maximumFrameRate;
 };
 
 QT_END_NAMESPACE