From ccfe0a1af77c3d13e81a913b25206d6a4a4747e4 Mon Sep 17 00:00:00 2001 From: Rishikesh Donadkar Date: Thu, 15 Sep 2022 17:17:34 +0530 Subject: gstreamer: Provide framerate support for libcamerasrc 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 Signed-off-by: Umang Jain Tested-by: Umang Jain Reviewed-by: Kieran Bingham Reviewed-by: Umang Jain --- src/gstreamer/gstlibcamera-utils.cpp | 78 ++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) (limited to 'src/gstreamer/gstlibcamera-utils.cpp') diff --git a/src/gstreamer/gstlibcamera-utils.cpp b/src/gstreamer/gstlibcamera-utils.cpp index 244a4a79..64d19701 100644 --- a/src/gstreamer/gstlibcamera-utils.cpp +++ b/src/gstreamer/gstlibcamera-utils.cpp @@ -8,6 +8,7 @@ #include "gstlibcamera-utils.h" +#include #include using namespace libcamera; @@ -407,6 +408,83 @@ gst_libcamera_configure_stream_from_caps(StreamConfiguration &stream_cfg, } } +void gst_libcamera_get_framerate_from_caps(GstCaps *caps, + GstStructure *element_caps) +{ + GstStructure *s = gst_caps_get_structure(caps, 0); + /* + * Default to 30 fps. If the "framerate" fraction is invalid below, + * libcamerasrc will set 30fps as the framerate. + */ + gint fps_n = 30, 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"); + } + + gst_structure_set(element_caps, "framerate", GST_TYPE_FRACTION, + fps_n, fps_d, nullptr); +} + +void gst_libcamera_clamp_and_set_frameduration(ControlList &initCtrls, + const ControlInfoMap &cam_ctrls, + GstStructure *element_caps) +{ + gint fps_caps_n, fps_caps_d; + + if (!gst_structure_has_field_typed(element_caps, "framerate", GST_TYPE_FRACTION)) + return; + + auto iterFrameDuration = cam_ctrls.find(controls::FrameDurationLimits.id()); + if (iterFrameDuration == cam_ctrls.end()) { + GST_WARNING("FrameDurationLimits not found in camera controls."); + return; + } + + const GValue *framerate = gst_structure_get_value(element_caps, "framerate"); + + fps_caps_n = gst_value_get_fraction_numerator(framerate); + fps_caps_d = gst_value_get_fraction_denominator(framerate); + + int64_t target_duration = (fps_caps_d * 1000000.0) / fps_caps_n; + int64_t min_frame_duration = iterFrameDuration->second.min().get(); + int64_t max_frame_duration = iterFrameDuration->second.max().get(); + + int64_t frame_duration = std::clamp(target_duration, + min_frame_duration, + max_frame_duration); + + if (frame_duration != target_duration) { + gint framerate_clamped = 1000000 / frame_duration; + + /* + * Update the clamped framerate which then will be exposed in + * downstream caps. + */ + gst_structure_set(element_caps, "framerate", GST_TYPE_FRACTION, + framerate_clamped, 1, nullptr); + } + + initCtrls.set(controls::FrameDurationLimits, + { frame_duration, frame_duration }); +} + +void gst_libcamera_framerate_to_caps(GstCaps *caps, const GstStructure *element_caps) +{ + const GValue *framerate = gst_structure_get_value(element_caps, "framerate"); + if (!GST_VALUE_HOLDS_FRACTION(framerate)) + return; + + GstStructure *s = gst_caps_get_structure(caps, 0); + gint fps_caps_n, fps_caps_d; + + fps_caps_n = gst_value_get_fraction_numerator(framerate); + fps_caps_d = gst_value_get_fraction_denominator(framerate); + + gst_structure_set(s, "framerate", GST_TYPE_FRACTION, fps_caps_n, fps_caps_d, nullptr); +} + #if !GST_CHECK_VERSION(1, 17, 1) gboolean gst_task_resume(GstTask *task) -- cgit v1.2.1