[libcamera-devel] [PATCH v4 2/2] gstreamer: Provide framerate support for libcamerasrc.
Umang Jain
umang.jain at ideasonboard.com
Mon Sep 12 12:50:29 CEST 2022
Hi Rishi,
Thank you for the patch,
Looks the the patch is getting in shape now... :-)
On 9/12/22 3:26 PM, Rishikesh Donadkar wrote:
> Add a field of the type ControlList to GstLibcameraSrcState.
>
> Get the framerate from the caps and convert it to FrameDuration.
> Clamp the frame_duration between the min/max FrameDuration supported
> by the camera and set the FrameDurationLimits control in the initControls_
>
> Solve the complications in exposing the correct framerate due to loss in
> precision as a result of casting the frameduration to int64_t(which is
> required in libcamera to set the FrameDurationLimits control).
>
> Example -
>
> * Suppose the framerate requested is 35/1. The framerate is read form
> the caps in the from of fraction that has a numerator and
> denominator.
>
> * Converting to FrameDuration (in microseconds)
> (1 * 10^6) / 35 = 28571.4286
> int64_t frame_duration = 28571
> (the precision here is lost.)
> * To expose the framerate in caps, Inverting the frame_duration to get
> back the framerate and converting to Seconds.
> double framerate = 10^6 / 28571
> and
> 10^6/28571 which is close but not equal to 35/1 will fail the negotiation.
>
> To solve the above problem, Store the framerate requested in the peer
> element caps in a container GstStructure, to be retrieved later.
>
> Get the control::FrameDurationLimits value that was set previously,
> convert to framerate and if it is equal to the one requested, set the
> framerate in the caps, else set the framerate to whatever is obtained
> from inverting the controls::FrameDurationLimits.
>
> Pass the initControls_ at camera->start().
>
> Signed-off-by: Rishikesh Donadkar <rishikeshdonadkar at gmail.com>
> ---
> src/gstreamer/gstlibcamera-utils.cpp | 69 ++++++++++++++++++++++++++++
> src/gstreamer/gstlibcamera-utils.h | 7 +++
> src/gstreamer/gstlibcamerasrc.cpp | 16 ++++++-
> 3 files changed, 91 insertions(+), 1 deletion(-)
>
> diff --git a/src/gstreamer/gstlibcamera-utils.cpp b/src/gstreamer/gstlibcamera-utils.cpp
> index 4df5dd6c..907ceab9 100644
> --- a/src/gstreamer/gstlibcamera-utils.cpp
> +++ b/src/gstreamer/gstlibcamera-utils.cpp
> @@ -8,6 +8,7 @@
>
> #include "gstlibcamera-utils.h"
>
> +#include <libcamera/control_ids.h>
> #include <libcamera/formats.h>
>
> using namespace libcamera;
> @@ -405,6 +406,74 @@ gst_libcamera_configure_stream_from_caps(StreamConfiguration &stream_cfg,
> }
> }
>
> +void gst_libcamera_get_framerate_from_caps([[maybe_unused]] GstCaps *caps,
> + GstStructure *container)
> +{
> + GstStructure *s = gst_caps_get_structure(caps, 0);
> + gint fps_n = -1, fps_d = -1;
> +
> + if (gst_structure_has_field_typed(s, "framerate", GST_TYPE_FRACTION)) {
> + if (!gst_structure_get_fraction(s, "framerate", &fps_n, &fps_d)) {
> + GST_WARNING("invalid framerate in the caps.");
s/invalid/Invalid
> + return;
> + }
> + }
> +
> + if (fps_n < 0 || fps_d < 0)
should it be combined with above if block, as this seems invalid as well...
if (!gst_structure_get_fraction(s, "framerate", &fps_n, &fps_d) &&
(fps_n < 0 || fps_d < 0)) {
GST_WARNING(...);
...
}
> + return;
> +
> + gst_structure_set(container, "framerate", GST_TYPE_FRACTION, fps_n, fps_d, nullptr);
> +}
> +
> +void gst_libcamera_clamp_and_set_frameduration(ControlList &controls, const ControlInfoMap &camera_controls,
> + const GstStructure *container)
> +{
> + gint fps_caps_n, fps_caps_d;
> + const GValue *framerate = gst_structure_get_value(container, "framerate");
> +
> + if (!gst_structure_has_field_typed(container, "framerate", GST_TYPE_FRACTION))
> + return;
> +
> + auto iterFrameDuration = camera_controls.find(controls::FrameDurationLimits.id());
> + if (iterFrameDuration == camera_controls.end())
This is a serious condition to be honest, that the camera doesn't give
FrameDurationLimits and we are trying to set framerate ....
I think we should introduce here a warning
> + return;
> +
> + fps_caps_n = gst_value_get_fraction_numerator(framerate);
> + fps_caps_d = gst_value_get_fraction_denominator(framerate);
> +
> + int64_t frame_duration = (fps_caps_d * 1000000.0) / fps_caps_n;
> + int64_t min_frame_duration = iterFrameDuration->second.min().get<int64_t>();
> + int64_t max_frame_duration = iterFrameDuration->second.max().get<int64_t>();
> +
> + if (frame_duration < min_frame_duration) {
> + frame_duration = min_frame_duration;
> + } else if (frame_duration > max_frame_duration) {
> + frame_duration = max_frame_duration;
> + }
> +
> + controls.set(controls::FrameDurationLimits,
> + Span<const int64_t, 2>({ frame_duration, frame_duration }));
> +}
> +
> +void gst_libcamera_framerate_to_caps(const ControlList &controls, GstCaps *caps, const GValue *container)
> +{
> + if (!GST_VALUE_HOLDS_FRACTION(container))
> + return;
> +
> + GstStructure *s = gst_caps_get_structure(caps, 0);
> + gint fps_n, fps_d, fps_caps_n, fps_caps_d;
> +
> + fps_caps_n = gst_value_get_fraction_numerator(container);
> + fps_caps_d = gst_value_get_fraction_denominator(container);
> + double framerate = 1000000 / controls.get(controls::FrameDurationLimits).value()[0];
> + gst_util_double_to_fraction(framerate, &fps_n, &fps_d);
> +
> + if (fps_caps_n / fps_caps_d == fps_n / fps_d)
> + gst_structure_set(s, "framerate", GST_TYPE_FRACTION, fps_caps_n, fps_caps_d, nullptr);
> + else
> + gst_structure_set(s, "framerate", GST_TYPE_FRACTION, fps_n, fps_d, nullptr);
I think we can even simplify all this now that we have a GValue
container to work with.
Would it be possible to save the fraction for min/max frame_duration
cases ( if..elseif {} in gst_libcamera_clamp_and_set_frameduration())
and update the container with that fraction.
... and simply use the container's framrate num/denum value here instead
of doing all the conversion / comparision?
I think it will get simpler that way , no?
> +}
> +
> #if !GST_CHECK_VERSION(1, 17, 1)
> gboolean
> gst_task_resume(GstTask *task)
> diff --git a/src/gstreamer/gstlibcamera-utils.h b/src/gstreamer/gstlibcamera-utils.h
> index 164189a2..bc04b073 100644
> --- a/src/gstreamer/gstlibcamera-utils.h
> +++ b/src/gstreamer/gstlibcamera-utils.h
> @@ -9,6 +9,7 @@
> #pragma once
>
> #include <libcamera/camera_manager.h>
> +#include <libcamera/controls.h>
> #include <libcamera/stream.h>
>
> #include <gst/gst.h>
> @@ -18,6 +19,12 @@ GstCaps *gst_libcamera_stream_formats_to_caps(const libcamera::StreamFormats &fo
> GstCaps *gst_libcamera_stream_configuration_to_caps(const libcamera::StreamConfiguration &stream_cfg);
> void gst_libcamera_configure_stream_from_caps(libcamera::StreamConfiguration &stream_cfg,
> GstCaps *caps);
> +void gst_libcamera_get_framerate_from_caps(GstCaps *caps, GstStructure *container);
> +void gst_libcamera_clamp_and_set_frameduration(libcamera::ControlList &controls,
> + const libcamera::ControlInfoMap &camera_controls, const GstStructure *container);
> +void gst_libcamera_framerate_to_caps(const libcamera::ControlList &controls, GstCaps *caps,
> + const GValue *container);
> +
> #if !GST_CHECK_VERSION(1, 17, 1)
> gboolean gst_task_resume(GstTask *task);
> #endif
> diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> index 1ee1d08a..5cdf23a1 100644
> --- a/src/gstreamer/gstlibcamerasrc.cpp
> +++ b/src/gstreamer/gstlibcamerasrc.cpp
> @@ -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;
>
> + GstStructure *container = gst_structure_new_empty("container");
> +
> GST_DEBUG_OBJECT(self, "Streaming thread has started");
>
> gint stream_id_num = 0;
> @@ -496,6 +499,7 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
> /* Retrieve the supported caps. */
> g_autoptr(GstCaps) filter = gst_libcamera_stream_formats_to_caps(stream_cfg.formats());
> g_autoptr(GstCaps) caps = gst_pad_peer_query_caps(srcpad, filter);
> +
spurious emptry line, remove it
> if (gst_caps_is_empty(caps)) {
> flow_ret = GST_FLOW_NOT_NEGOTIATED;
> break;
> @@ -504,6 +508,7 @@ 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, container);
> }
>
> if (flow_ret != GST_FLOW_OK)
> @@ -524,6 +529,10 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
> return;
> }
>
> + /* Check frame duration bounds within controls::FrameDurationLimits */
> + gst_libcamera_clamp_and_set_frameduration(state->initControls_,
> + state->cam_->controls(), container);
> +
> /*
> * Regardless if it has been modified, create clean caps and push the
> * caps event. Downstream will decide if the caps are acceptable.
> @@ -531,8 +540,11 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
> for (gsize i = 0; i < state->srcpads_.size(); i++) {
> GstPad *srcpad = state->srcpads_[i];
> const StreamConfiguration &stream_cfg = state->config_->at(i);
> + const GValue *framerate = gst_structure_get_value(container, "framerate");
>
> g_autoptr(GstCaps) caps = gst_libcamera_stream_configuration_to_caps(stream_cfg);
> + gst_libcamera_framerate_to_caps(state->initControls_, caps, framerate);
> +
It would be interesting to test on a multistream platform and see if
you get different framerates for each srcpad / loop iteration? Any ideas
how should we handle ?
> if (!gst_pad_push_event(srcpad, gst_event_new_caps(caps))) {
> flow_ret = GST_FLOW_NOT_NEGOTIATED;
> break;
> @@ -566,7 +578,7 @@ 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)),
> @@ -576,6 +588,8 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
> }
>
> done:
> + state->initControls_.clear();
> + g_free(container);
> switch (flow_ret) {
> case GST_FLOW_NOT_NEGOTIATED:
> GST_ELEMENT_FLOW_ERROR(self, flow_ret);
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