/* SPDX-License-Identifier: LGPL-2.1-or-later */ /* * Copyright (C) 2019, Collabora Ltd. * Author: Nicolas Dufresne <nicolas.dufresne@collabora.com> * * gstlibcamerasrc.cpp - GStreamer Capture Element */ /** * \todo The following is a list of items that needs implementation in the GStreamer plugin * - Implement GstElement::send_event * + Allowing application to send EOS * + Allowing application to use FLUSH/FLUSH_STOP * + Prevent the main thread from accessing streaming thread * - Implement renegotiation (even if slow) * - Implement GstElement::request-new-pad (multi stream) * + Evaluate if a single streaming thread is fine * - Add application driven request (snapshot) * - Add framerate control * - Add buffer importation support * * Requires new libcamera API: * - Add framerate negotiation support * - Add colorimetry support * - Add timestamp support * - Use unique names to select the camera devices * - Add GstVideoMeta support (strides and offsets) * * \todo libcamera UVC drivers picks the lowest possible resolution first, this * should be fixed so that we get a decent resolution and framerate for the * role by default. */ #include "gstlibcamerasrc.h" #include <queue> #include <vector> #include <gst/base/base.h> #include <libcamera/camera.h> #include <libcamera/camera_manager.h> #include "gstlibcameraallocator.h" #include "gstlibcamerapad.h" #include "gstlibcamerapool.h" #include "gstlibcamera-utils.h" using namespace libcamera; GST_DEBUG_CATEGORY_STATIC(source_debug); #define GST_CAT_DEFAULT source_debug struct RequestWrap { RequestWrap(Request *request); ~RequestWrap(); void attachBuffer(GstBuffer *buffer); GstBuffer *detachBuffer(Stream *stream); /* For ptr comparison only. */ Request *request_; std::map<Stream *, GstBuffer *> buffers_; }; RequestWrap::RequestWrap(Request *request) : request_(request) { } RequestWrap::~RequestWrap() { for (std::pair<Stream *const, GstBuffer *> &item : buffers_) { if (item.second) gst_buffer_unref(item.second); } delete request_; } void RequestWrap::attachBuffer(GstBuffer *buffer) { FrameBuffer *fb = gst_libcamera_buffer_get_frame_buffer(buffer); Stream *stream = gst_libcamera_buffer_get_stream(buffer); request_->addBuffer(stream, fb); auto item = buffers_.find(stream); if (item != buffers_.end()) { gst_buffer_unref(item->second); item->second = buffer; } else { buffers_[stream] = buffer; } } GstBuffer *RequestWrap::detachBuffer(Stream *stream) { GstBuffer *buffer = nullptr; auto item = buffers_.find(stream); if (item != buffers_.end()) { buffer = item->second; item->second = nullptr; } return buffer; } /* Used for C++ object with destructors. */ struct GstLibcameraSrcState { GstLibcameraSrc *src_; std::unique_ptr<CameraManager> cm_; std::shared_ptr<Camera> cam_; std::unique_ptr<CameraConfiguration> config_; std::vector<GstPad *> srcpads_; std::queue<std::unique_ptr<RequestWrap>> requests_; void requestCompleted(Request *request); }; struct _GstLibcameraSrc { GstElement parent; GRecMutex stream_lock; GstTask *task; gchar *camera_name; GstLibcameraSrcState *state; GstLibcameraAllocator *allocator; GstFlowCombiner *flow_combiner; }; enum { PROP_0, PROP_CAMERA_NAME }; G_DEFINE_TYPE_WITH_CODE(GstLibcameraSrc, gst_libcamera_src, GST_TYPE_ELEMENT, GST_DEBUG_CATEGORY_INIT(source_debug, "libcamerasrc", 0, "libcamera Source")) #define TEMPLATE_CAPS GST_STATIC_CAPS("video/x-raw; image/jpeg") /* For the simple case, we have a src pad that is always present. */ GstStaticPadTemplate src_template = { "src", GST_PAD_SRC, GST_PAD_ALWAYS, TEMPLATE_CAPS }; /* More pads can be requested in state < PAUSED */ GstStaticPadTemplate request_src_template = { "src_%s", GST_PAD_SRC, GST_PAD_REQUEST, TEMPLATE_CAPS }; void GstLibcameraSrcState::requestCompleted(Request *request) { GLibLocker lock(GST_OBJECT(src_)); GST_DEBUG_OBJECT(src_, "buffers are ready"); std::unique_ptr<RequestWrap> wrap = std::move(requests_.front()); requests_.pop(); g_return_if_fail(wrap->request_ == request); if ((request->status() == Request::RequestCancelled)) { GST_DEBUG_OBJECT(src_, "Request was cancelled"); return; } GstBuffer *buffer; for (GstPad *srcpad : srcpads_) { Stream *stream = gst_libcamera_pad_get_stream(srcpad); buffer = wrap->detachBuffer(stream); FrameBuffer *fb = gst_libcamera_buffer_get_frame_buffer(buffer); if (GST_ELEMENT_CLOCK(src_)) { GstClockTime gst_base_time = GST_ELEMENT(src_)->base_time; GstClockTime gst_now = gst_clock_get_time(GST_ELEMENT_CLOCK(src_)); /* \todo Need to expose which reference clock the timestamp relates to. */ GstClockTime sys_now = g_get_monotonic_time() * 1000; /* Deduced from: sys_now - sys_base_time == gst_now - gst_base_time */ GstClockTime sys_base_time = sys_now - (gst_now - gst_base_time); GST_BUFFER_PTS(buffer) = fb->metadata().timestamp - sys_base_time; gst_libcamera_pad_set_latency(srcpad, sys_now - fb->metadata().timestamp); } else { GST_BUFFER_PTS(buffer) = 0; } GST_BUFFER_OFFSET(buffer) = fb->metadata().sequence; GST_BUFFER_OFFSET_END(buffer) = fb->metadata().sequence; gst_libcamera_pad_queue_buffer(srcpad, buffer); } gst_libcamera_resume_task(this->src_->task); } static bool gst_libcamera_src_open(GstLibcameraSrc *self) { std::unique_ptr<CameraManager> cm = std::make_unique<CameraManager>(); std::shared_ptr<Camera> cam; gint ret = 0; GST_DEBUG_OBJECT(self, "Opening camera device ..."); ret = cm->start(); if (ret) { GST_ELEMENT_ERROR(self, LIBRARY, INIT, ("Failed listing cameras."), ("libcamera::CameraMananger::start() failed: %s", g_strerror(-ret))); return false; } g_autofree gchar *camera_name = nullptr; { GLibLocker lock(GST_OBJECT(self)); if (self->camera_name) camera_name = g_strdup(self->camera_name); } if (camera_name) { cam = cm->get(self->camera_name); if (!cam) { GST_ELEMENT_ERROR(self, RESOURCE, NOT_FOUND, ("Could not find a camera named '%s'.", self->camera_name), ("libcamera::CameraMananger::get() returned nullptr")); return false; } } else { if (cm->cameras().empty()) { GST_ELEMENT_ERROR(self, RESOURCE, NOT_FOUND, ("Could not find any supported camera on this system."), ("libcamera::CameraMananger::cameras() is empty")); return false; } cam = cm->cameras()[0]; } GST_INFO_OBJECT(self, "Using camera '%s'", cam->id().c_str()); ret = cam->acquire(); if (ret) { GST_ELEMENT_ERROR(self, RESOURCE, BUSY, ("Camera '%s' is already in use.", cam->id().c_str()), ("libcamera::Camera::acquire() failed: %s", g_strerror(ret))); return false; } cam->requestCompleted.connect(self->state, &GstLibcameraSrcState::requestCompleted); /* No need to lock here, we didn't start our threads yet. */ self->state->cm_ = std::move(cm); self->state->cam_ = cam; return true; } static void gst_libcamera_src_task_run(gpointer user_data) { GstLibcameraSrc *self = GST_LIBCAMERA_SRC(user_data); GstLibcameraSrcState *state = self->state; std::unique_ptr<Request> request = state->cam_->createRequest(); auto wrap = std::make_unique<RequestWrap>(request.get()); for (GstPad *srcpad : state->srcpads_) { GstLibcameraPool *pool = gst_libcamera_pad_get_pool(srcpad); GstBuffer *buffer; GstFlowReturn ret; ret = gst_buffer_pool_acquire_buffer(GST_BUFFER_POOL(pool), &buffer, nullptr); if (ret != GST_FLOW_OK) { /* * RequestWrap does not take ownership, and we won't be * queueing this one due to lack of buffers. */ request.reset(); break; } wrap->attachBuffer(buffer); } if (request) { GLibLocker lock(GST_OBJECT(self)); GST_TRACE_OBJECT(self, "Requesting buffers"); state->cam_->queueRequest(request.get()); state->requests_.push(std::move(wrap)); /* The request will be deleted in the completion handler. */ request.release(); } GstFlowReturn ret = GST_FLOW_OK; gst_flow_combiner_reset(self->flow_combiner); for (GstPad *srcpad : state->srcpads_) { ret = gst_libcamera_pad_push_pending(srcpad); ret = gst_flow_combiner_update_pad_flow(self->flow_combiner, srcpad, ret); } { /* * Here we need to decide if we want to pause or stop the task. This * needs to happen in lock step with the callback thread which may want * to resume the task. */ GLibLocker lock(GST_OBJECT(self)); if (ret != GST_FLOW_OK) { if (ret == GST_FLOW_EOS) { g_autoptr(GstEvent) eos = gst_event_new_eos(); guint32 seqnum = gst_util_seqnum_next(); gst_event_set_seqnum(eos, seqnum); for (GstPad *srcpad : state->srcpads_) gst_pad_push_event(srcpad, gst_event_ref(eos)); } else if (ret != GST_FLOW_FLUSHING) { GST_ELEMENT_FLOW_ERROR(self, ret); } gst_task_stop(self->task); return; } bool do_pause = true; for (GstPad *srcpad : state->srcpads_) { if (gst_libcamera_pad_has_pending(srcpad)) { do_pause = false; break; } } if (do_pause) gst_task_pause(self->task); } } static void gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread, gpointer user_data) { GstLibcameraSrc *self = GST_LIBCAMERA_SRC(user_data); GLibRecLocker lock(&self->stream_lock); GstLibcameraSrcState *state = self->state; GstFlowReturn flow_ret = GST_FLOW_OK; gint ret; GST_DEBUG_OBJECT(self, "Streaming thread has started"); guint group_id = gst_util_group_id_next(); StreamRoles roles; for (GstPad *srcpad : state->srcpads_) { /* Create stream-id and push stream-start. */ g_autofree gchar *stream_id = gst_pad_create_stream_id(srcpad, GST_ELEMENT(self), nullptr); GstEvent *event = gst_event_new_stream_start(stream_id); gst_event_set_group_id(event, group_id); gst_pad_push_event(srcpad, event); /* Collect the streams roles for the next iteration. */ roles.push_back(gst_libcamera_pad_get_role(srcpad)); } /* Generate the stream configurations, there should be one per pad. */ state->config_ = state->cam_->generateConfiguration(roles); /* * \todo Check if camera may increase or decrease the number of streams * regardless of the number of roles. */ g_assert(state->config_->size() == state->srcpads_.size()); for (gsize i = 0; i < state->srcpads_.size(); i++) { GstPad *srcpad = state->srcpads_[i]; StreamConfiguration &stream_cfg = state->config_->at(i); /* 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); if (gst_caps_is_empty(caps)) { flow_ret = GST_FLOW_NOT_NEGOTIATED; break; } /* Fixate caps and configure the stream. */ caps = gst_caps_make_writable(caps); gst_libcamera_configure_stream_from_caps(stream_cfg, caps); } if (flow_ret != GST_FLOW_OK) goto done; /* Validate the configuration. */ if (state->config_->validate() == CameraConfiguration::Invalid) { flow_ret = GST_FLOW_NOT_NEGOTIATED; goto done; } /* * Regardless if it has been modified, create clean caps and push the * caps event. Downstream will decide if the caps are acceptable. */ for (gsize i = 0; i < state->srcpads_.size(); i++) { GstPad *srcpad = state->srcpads_[i]; const StreamConfiguration &stream_cfg = state->config_->at(i); g_autoptr(GstCaps) caps = gst_libcamera_stream_configuration_to_caps(stream_cfg); if (!gst_pad_push_event(srcpad, gst_event_new_caps(caps))) { flow_ret = GST_FLOW_NOT_NEGOTIATED; break; } /* Send an open segment event with time format. */ GstSegment segment; gst_segment_init(&segment, GST_FORMAT_TIME); gst_pad_push_event(srcpad, gst_event_new_segment(&segment)); } ret = state->cam_->configure(state->config_.get()); if (ret) { GST_ELEMENT_ERROR(self, RESOURCE, SETTINGS, ("Failed to configure camera: %s", g_strerror(-ret)), ("Camera::configure() failed with error code %i", ret)); gst_task_stop(task); return; } self->allocator = gst_libcamera_allocator_new(state->cam_); if (!self->allocator) { GST_ELEMENT_ERROR(self, RESOURCE, NO_SPACE_LEFT, ("Failed to allocate memory"), ("gst_libcamera_allocator_new() failed.")); gst_task_stop(task); return; } self->flow_combiner = gst_flow_combiner_new(); for (gsize i = 0; i < state->srcpads_.size(); i++) { GstPad *srcpad = state->srcpads_[i]; const StreamConfiguration &stream_cfg = state->config_->at(i); GstLibcameraPool *pool = gst_libcamera_pool_new(self->allocator, stream_cfg.stream()); g_signal_connect_swapped(pool, "buffer-notify", G_CALLBACK(gst_libcamera_resume_task), task); gst_libcamera_pad_set_pool(srcpad, pool); gst_flow_combiner_add_pad(self->flow_combiner, srcpad); } ret = state->cam_->start(); if (ret) { GST_ELEMENT_ERROR(self, RESOURCE, SETTINGS, ("Failed to start the camera: %s", g_strerror(-ret)), ("Camera.start() failed with error code %i", ret)); gst_task_stop(task); return; } done: switch (flow_ret) { case GST_FLOW_NOT_NEGOTIATED: GST_ELEMENT_FLOW_ERROR(self, flow_ret); gst_task_stop(task); break; default: break; } } static void gst_libcamera_src_task_leave([[maybe_unused]] GstTask *task, [[maybe_unused]] GThread *thread, gpointer user_data) { GstLibcameraSrc *self = GST_LIBCAMERA_SRC(user_data); GstLibcameraSrcState *state = self->state; GST_DEBUG_OBJECT(self, "Streaming thread is about to stop"); state->cam_->stop(); for (GstPad *srcpad : state->srcpads_) gst_libcamera_pad_set_pool(srcpad, nullptr); g_clear_object(&self->allocator); g_clear_pointer(&self->flow_combiner, (GDestroyNotify)gst_flow_combiner_free); } static void gst_libcamera_src_close(GstLibcameraSrc *self) { GstLibcameraSrcState *state = self->state; gint ret; GST_DEBUG_OBJECT(self, "Releasing resources"); state->config_.reset(); ret = state->cam_->release(); if (ret) { GST_ELEMENT_WARNING(self, RESOURCE, BUSY, ("Camera '%s' is still in use.", state->cam_->id().c_str()), ("libcamera::Camera.release() failed: %s", g_strerror(-ret))); } state->cam_.reset(); state->cm_->stop(); state->cm_.reset(); } static void gst_libcamera_src_set_property(GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec) { GLibLocker lock(GST_OBJECT(object)); GstLibcameraSrc *self = GST_LIBCAMERA_SRC(object); switch (prop_id) { case PROP_CAMERA_NAME: g_free(self->camera_name); self->camera_name = g_value_dup_string(value); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec); break; } } static void gst_libcamera_src_get_property(GObject *object, guint prop_id, GValue *value, GParamSpec *pspec) { GLibLocker lock(GST_OBJECT(object)); GstLibcameraSrc *self = GST_LIBCAMERA_SRC(object); switch (prop_id) { case PROP_CAMERA_NAME: g_value_set_string(value, self->camera_name); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec); break; } } static GstStateChangeReturn gst_libcamera_src_change_state(GstElement *element, GstStateChange transition) { GstLibcameraSrc *self = GST_LIBCAMERA_SRC(element); GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS; GstElementClass *klass = GST_ELEMENT_CLASS(gst_libcamera_src_parent_class); ret = klass->change_state(element, transition); if (ret == GST_STATE_CHANGE_FAILURE) return ret; switch (transition) { case GST_STATE_CHANGE_NULL_TO_READY: if (!gst_libcamera_src_open(self)) return GST_STATE_CHANGE_FAILURE; break; case GST_STATE_CHANGE_READY_TO_PAUSED: /* This needs to be called after pads activation.*/ if (!gst_task_pause(self->task)) return GST_STATE_CHANGE_FAILURE; ret = GST_STATE_CHANGE_NO_PREROLL; break; case GST_STATE_CHANGE_PAUSED_TO_PLAYING: gst_task_start(self->task); break; case GST_STATE_CHANGE_PLAYING_TO_PAUSED: ret = GST_STATE_CHANGE_NO_PREROLL; break; case GST_STATE_CHANGE_PAUSED_TO_READY: /* * \todo this might require some thread unblocking in the future * if the streaming thread starts doing any kind of blocking * operations. If this was the case, we would need to do so * before pad deactivation, so before chaining to the parent * change_state function. */ gst_task_join(self->task); break; case GST_STATE_CHANGE_READY_TO_NULL: gst_libcamera_src_close(self); break; default: break; } return ret; } static void gst_libcamera_src_finalize(GObject *object) { GObjectClass *klass = G_OBJECT_CLASS(gst_libcamera_src_parent_class); GstLibcameraSrc *self = GST_LIBCAMERA_SRC(object); g_rec_mutex_clear(&self->stream_lock); g_clear_object(&self->task); g_free(self->camera_name); delete self->state; return klass->finalize(object); } static void gst_libcamera_src_init(GstLibcameraSrc *self) { GstLibcameraSrcState *state = new GstLibcameraSrcState(); GstPadTemplate *templ = gst_element_get_pad_template(GST_ELEMENT(self), "src"); g_rec_mutex_init(&self->stream_lock); self->task = gst_task_new(gst_libcamera_src_task_run, self, nullptr); gst_task_set_enter_callback(self->task, gst_libcamera_src_task_enter, self, nullptr); gst_task_set_leave_callback(self->task, gst_libcamera_src_task_leave, self, nullptr); gst_task_set_lock(self->task, &self->stream_lock); state->srcpads_.push_back(gst_pad_new_from_template(templ, "src")); gst_element_add_pad(GST_ELEMENT(self), state->srcpads_[0]); /* C-style friend. */ state->src_ = self; self->state = state; } static void gst_libcamera_src_class_init(GstLibcameraSrcClass *klass) { GstElementClass *element_class = GST_ELEMENT_CLASS(klass); GObjectClass *object_class = G_OBJECT_CLASS(klass); object_class->set_property = gst_libcamera_src_set_property; object_class->get_property = gst_libcamera_src_get_property; object_class->finalize = gst_libcamera_src_finalize; element_class->change_state = gst_libcamera_src_change_state; gst_element_class_set_metadata(element_class, "libcamera Source", "Source/Video", "Linux Camera source using libcamera", "Nicolas Dufresne <nicolas.dufresne@collabora.com"); gst_element_class_add_static_pad_template_with_gtype(element_class, &src_template, GST_TYPE_LIBCAMERA_PAD); gst_element_class_add_static_pad_template_with_gtype(element_class, &request_src_template, GST_TYPE_LIBCAMERA_PAD); GParamSpec *spec = g_param_spec_string("camera-name", "Camera Name", "Select by name which camera to use.", nullptr, (GParamFlags)(GST_PARAM_MUTABLE_READY | G_PARAM_CONSTRUCT | G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)); g_object_class_install_property(object_class, PROP_CAMERA_NAME, spec); }