NekoCWD/libcamera
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gstreamer: Provide framerate support for libcamerasrc

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Control the framerate by passing the controls::FrameDurationLimits
during Camera::start(). Framerate in gstreamer is expressed as
GST_TYPE_FRACTION so we maximise on maintaining it as a fraction
throughout and only do arithematic computations as and when required
(to compute frame-duration and vice-versa).

To weed out abritrary framerate as input, place the clamping via the
controls::FrameDurationLimits provided after camera::configure() phase.
This is handled by a helper function
gst_libcamera_clamp_and_set_frameduration().

Set the bound checked framerate (done in the above mentioned helper)
into the caps and pass the ControlList containing the frame-duration
to Camera::start(ctrls).

Signed-off-by: Rishikesh Donadkar <rishikeshdonadkar@gmail.com>
Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Tested-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
This commit is contained in:
Rishikesh Donadkar 2022-09-15 17:17:34 +05:30 • committed by Umang Jain
parent 872588301f
commit ccfe0a1af7
3 changed files with 97 additions and 1 deletions
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13
src/gstreamer/gstlibcamerasrc.cpp
View file

@ -131,6 +131,7 @@ struct GstLibcameraSrcState {
std::queue<std::unique_ptr<RequestWrap>> completedRequests_
LIBCAMERA_TSA_GUARDED_BY(lock_);
ControlList initControls_;
guint group_id_;
int queueRequest();
@ -462,6 +463,8 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
GstFlowReturn flow_ret = GST_FLOW_OK;
gint ret;
g_autoptr(GstStructure) element_caps = gst_structure_new_empty("caps");
GST_DEBUG_OBJECT(self, "Streaming thread has started");
gint stream_id_num = 0;
@ -504,6 +507,7 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
/* Fixate caps and configure the stream. */
caps = gst_caps_make_writable(caps);
gst_libcamera_configure_stream_from_caps(stream_cfg, caps);
gst_libcamera_get_framerate_from_caps(caps, element_caps);
}
if (flow_ret != GST_FLOW_OK)
@ -525,6 +529,10 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
goto done;
}
/* Check frame duration bounds within controls::FrameDurationLimits */
gst_libcamera_clamp_and_set_frameduration(state->initControls_,
state->cam_->controls(), element_caps);
/*
* Regardless if it has been modified, create clean caps and push the
* caps event. Downstream will decide if the caps are acceptable.
@ -534,6 +542,8 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
const StreamConfiguration &stream_cfg = state->config_->at(i);
g_autoptr(GstCaps) caps = gst_libcamera_stream_configuration_to_caps(stream_cfg);
gst_libcamera_framerate_to_caps(caps, element_caps);
if (!gst_pad_push_event(srcpad, gst_event_new_caps(caps))) {
flow_ret = GST_FLOW_NOT_NEGOTIATED;
break;
@ -567,7 +577,7 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
gst_flow_combiner_add_pad(self->flow_combiner, srcpad);
}
ret = state->cam_->start();
ret = state->cam_->start(&state->initControls_);
if (ret) {
GST_ELEMENT_ERROR(self, RESOURCE, SETTINGS,
("Failed to start the camera: %s", g_strerror(-ret)),
@ -577,6 +587,7 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
}
done:
state->initControls_.clear();
switch (flow_ret) {
case GST_FLOW_NOT_NEGOTIATED:
GST_ELEMENT_FLOW_ERROR(self, flow_ret);