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-rw-r--r--src/libcamera/include/v4l2_videodevice.h8
-rw-r--r--src/libcamera/v4l2_videodevice.cpp75
2 files changed, 82 insertions, 1 deletions
diff --git a/src/libcamera/include/v4l2_videodevice.h b/src/libcamera/include/v4l2_videodevice.h
index ee63d28d..a0409e59 100644
--- a/src/libcamera/include/v4l2_videodevice.h
+++ b/src/libcamera/include/v4l2_videodevice.h
@@ -224,6 +224,9 @@ public:
int queueBuffer(FrameBuffer *buffer);
Signal<FrameBuffer *> bufferReady;
+ int setFrameStartEnabled(bool enable);
+ Signal<uint32_t> frameStart;
+
int streamOn();
int streamOff();
@@ -262,6 +265,8 @@ private:
void bufferAvailable(EventNotifier *notifier);
FrameBuffer *dequeueBuffer();
+ void eventAvailable(EventNotifier *notifier);
+
V4L2Capability caps_;
enum v4l2_buf_type bufferType_;
@@ -271,6 +276,9 @@ private:
std::map<unsigned int, FrameBuffer *> queuedBuffers_;
EventNotifier *fdBufferNotifier_;
+ EventNotifier *fdEventNotifier_;
+
+ bool frameStartEnabled_;
};
class V4L2M2MDevice
diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index fae4f078..8d642be0 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -544,7 +544,8 @@ const std::string V4L2DeviceFormat::toString() const
* \param[in] deviceNode The file-system path to the video device node
*/
V4L2VideoDevice::V4L2VideoDevice(const std::string &deviceNode)
- : V4L2Device(deviceNode), cache_(nullptr), fdBufferNotifier_(nullptr)
+ : V4L2Device(deviceNode), cache_(nullptr), fdBufferNotifier_(nullptr),
+ fdEventNotifier_(nullptr), frameStartEnabled_(false)
{
/*
* We default to an MMAP based CAPTURE video device, however this will
@@ -637,6 +638,10 @@ int V4L2VideoDevice::open()
fdBufferNotifier_->activated.connect(this, &V4L2VideoDevice::bufferAvailable);
fdBufferNotifier_->setEnabled(false);
+ fdEventNotifier_ = new EventNotifier(fd(), EventNotifier::Exception);
+ fdEventNotifier_->activated.connect(this, &V4L2VideoDevice::eventAvailable);
+ fdEventNotifier_->setEnabled(false);
+
LOG(V4L2, Debug)
<< "Opened device " << caps_.bus_info() << ": "
<< caps_.driver() << ": " << caps_.card();
@@ -726,6 +731,10 @@ int V4L2VideoDevice::open(int handle, enum v4l2_buf_type type)
fdBufferNotifier_->activated.connect(this, &V4L2VideoDevice::bufferAvailable);
fdBufferNotifier_->setEnabled(false);
+ fdEventNotifier_ = new EventNotifier(fd(), EventNotifier::Exception);
+ fdEventNotifier_->activated.connect(this, &V4L2VideoDevice::eventAvailable);
+ fdEventNotifier_->setEnabled(false);
+
LOG(V4L2, Debug)
<< "Opened device " << caps_.bus_info() << ": "
<< caps_.driver() << ": " << caps_.card();
@@ -743,6 +752,7 @@ void V4L2VideoDevice::close()
releaseBuffers();
delete fdBufferNotifier_;
+ delete fdEventNotifier_;
V4L2Device::close();
}
@@ -1571,11 +1581,74 @@ FrameBuffer *V4L2VideoDevice::dequeueBuffer()
}
/**
+ * \brief Slot to handle V4L2 events from the V4L2 video device
+ * \param[in] notifier The event notifier
+ *
+ * When this slot is called, a V4L2 event is available to be dequeued from the
+ * device.
+ */
+void V4L2VideoDevice::eventAvailable(EventNotifier *notifier)
+{
+ struct v4l2_event event{};
+ int ret = ioctl(VIDIOC_DQEVENT, &event);
+ if (ret < 0) {
+ LOG(V4L2, Error)
+ << "Failed to dequeue event, disabling event notifier";
+ fdEventNotifier_->setEnabled(false);
+ return;
+ }
+
+ if (event.type != V4L2_EVENT_FRAME_SYNC) {
+ LOG(V4L2, Error)
+ << "Spurious event (" << event.type
+ << "), disabling event notifier";
+ fdEventNotifier_->setEnabled(false);
+ return;
+ }
+
+ frameStart.emit(event.u.frame_sync.frame_sequence);
+}
+
+/**
* \var V4L2VideoDevice::bufferReady
* \brief A Signal emitted when a framebuffer completes
*/
/**
+ * \brief Enable or disable frame start event notification
+ * \param[in] enable True to enable frame start events, false to disable them
+ *
+ * This function enables or disables generation of frame start events. Once
+ * enabled, the events are signalled through the frameStart signal.
+ *
+ * \return 0 on success, a negative error code otherwise
+ */
+int V4L2VideoDevice::setFrameStartEnabled(bool enable)
+{
+ if (frameStartEnabled_ == enable)
+ return 0;
+
+ struct v4l2_event_subscription event{};
+ event.type = V4L2_EVENT_FRAME_SYNC;
+
+ unsigned long request = enable ? VIDIOC_SUBSCRIBE_EVENT
+ : VIDIOC_UNSUBSCRIBE_EVENT;
+ int ret = ioctl(request, &event);
+ if (enable && ret)
+ return ret;
+
+ fdEventNotifier_->setEnabled(enable);
+ frameStartEnabled_ = enable;
+
+ return ret;
+}
+
+/**
+ * \var V4L2VideoDevice::frameStart
+ * \brief A Signal emitted when capture of a frame has started
+ */
+
+/**
* \brief Start the video stream
* \return 0 on success or a negative error code otherwise
*/