fix(video): use float framerates also for V4L2

also make -1 the default value for the framerate

src/platform/camera/v4l2.cpp

@@ -91,17 +91,17 @@ fail:
     return -1;
 }
 
-static QVector<unsigned short> getDeviceModeFramerates(int fd, unsigned w, unsigned h,
+static QVector<float> getDeviceModeFramerates(int fd, unsigned w, unsigned h,
                                                        uint32_t pixelFormat)
 {
-    QVector<unsigned short> rates;
+    QVector<float> rates;
     v4l2_frmivalenum vfve{};
     vfve.pixel_format = pixelFormat;
     vfve.height = h;
     vfve.width = w;
 
     while (!ioctl(fd, VIDIOC_ENUM_FRAMEINTERVALS, &vfve)) {
-        int rate;
+        float rate;
         switch (vfve.type) {
         case V4L2_FRMSIZE_TYPE_DISCRETE:
             rate = vfve.discrete.denominator / vfve.discrete.numerator;
@@ -154,9 +154,9 @@ QVector<VideoMode> v4l2::getDeviceModes(QString devName)
                 continue;
             }
 
-            QVector<unsigned short> rates =
+            QVector<float> rates =
                 getDeviceModeFramerates(fd, mode.width, mode.height, vfd.pixelformat);
-            for (unsigned short rate : rates) {
+            for (float rate : rates) {
                 mode.FPS = rate;
                 if (!modes.contains(mode))
                     modes.append(std::move(mode));

src/video/camerasource.cpp

@@ -284,8 +284,9 @@ void CameraSource::openDevice()
 
     // We need to open the device as many time as we already have subscribers,
     // otherwise the device could get closed while we still have subscribers
-    for (int i = 0; i < subscriptions; ++i)
+    for (int i = 0; i < subscriptions; ++i) {
         device->open();
+    }
 
     // Find the first video stream, if any
     for (unsigned i = 0; i < device->context->nb_streams; ++i) {

src/video/videomode.cpp

@@ -31,15 +31,15 @@
  *
  * @var float VideoMode::FPS
  * @brief Frames per second supported by the device at this resolution
+ * @note a value < 0 indicates an invalid value
  */
 
-VideoMode::VideoMode(int width, int height, int x, int y, float FPS, int format)
+VideoMode::VideoMode(int width, int height, int x, int y, float FPS)
     : width(width)
     , height(height)
     , x(x)
     , y(y)
     , FPS(FPS)
-    , pixel_format(format)
 {
 }
 
@@ -48,8 +48,6 @@ VideoMode::VideoMode(QRect rect)
     , height(rect.height())
     , x(rect.x())
     , y(rect.y())
-    , FPS(0)
-    , pixel_format(0)
 {
 }
 
@@ -74,5 +72,5 @@ uint32_t VideoMode::norm(const VideoMode& other) const
  */
 VideoMode::operator bool() const
 {
-    return width || height || FPS;
+    return width || height || (FPS < 0);
 }

src/video/videomode.h

@@ -27,10 +27,10 @@ struct VideoMode
 {
     int width, height;
     int x, y;
-    float FPS;
+    float FPS = -1.0f;
-    uint32_t pixel_format;
+    uint32_t pixel_format = 0;
 
-    VideoMode(int width = 0, int height = 0, int x = 0, int y = 0, float FPS = 0.0f, int format = 0);
+    VideoMode(int width = 0, int height = 0, int x = 0, int y = 0, float FPS = -1.0f);
 
     explicit VideoMode(QRect rect);
 

src/widget/form/settings/avform.cpp

@@ -319,14 +319,15 @@ void AVForm::fillCameraModesComboBox()
 int AVForm::searchPreferredIndex()
 {
     QRect prefRes = videoSettings->getCamVideoRes();
-    quint16 prefFPS = videoSettings->getCamVideoFPS();
+    float prefFPS = videoSettings->getCamVideoFPS();
 
     for (int i = 0; i < videoModes.size(); ++i) {
         VideoMode mode = videoModes[i];
         if (mode.width == prefRes.width() && mode.height == prefRes.height()
-            && static_cast<quint16>(mode.FPS) == prefFPS)
+                && (qAbs(mode.FPS - prefFPS) < 0.0001f)) {
             return i;
         }
+    }
 
     return -1;
 }