I modified simple-cam to use the old mmapping code from rpicam-apps before using dmabufs, as shown below.Another thing that causes quite a bit of slowdown is mmapping buffers on the fly on every request completion. A better approach would be mapping the buffers on startup, holding onto the buffer pointers, and doing a pointer look up when the buffer gets completed in the request when you want to access the data. This works because the buffers are allocated once on startup and recycled at runtime.
Again rpicam-apps and picamera2 do this as well.
Code:
allocators = new FrameBufferAllocator(cameras);for (StreamConfiguration &cfg : *config) {Stream *stream = cfg.stream();if (allocator->allocate(stream) < 0)std::cerr << "Can't allocate buffers" << std::endl;for (const std::unique_ptr<FrameBuffer> &buffer : allocator->buffers(stream)){size_t buffer_size = 0;for (unsigned i = 0; i < buffer->planes().size(); i++){const FrameBuffer::Plane &plane = buffer->planes()[i];buffer_size += plane.length;if (j == buffer->planes().size() -1 || plane.fd.get() != buffer->planes()[i+1].fd.get()){void *memory = mmap(NULL, buffer_size, PROT_READ | PROT_WRITE, MAP_SHARED, plane.fd.get(), 0);mapped_buffers_[buffer.get()].push_back(Span<uint8_t>(static_cast<uint8_t*>(memory), buffer_size));buffer_size = 0;}}frame_buffers_[stream].push(buffer.get());}size_t allocated = allocator->buffers(cfg.stream()).size();std::cout << "Allocated " << allocated << " buffers for stream" << std::endl;}makeRequests();Code:
static void processRequest(Request *request){float framerate = 0;auto ts = request->metadata().get(controls::SensorTimestamp);uint64_t timestamp = ts ? *ts : request->buffers().begin()->second->metadata().timestamp;if (last_timestamp_ == 0 || last_timestamp_ == timestamp)framerate = 0;elseframerate = 1e9 / (timestamp - last_timestamp_);last_timestamp_ = timestamp;const Request::BufferMap &buffers = request->buffers();for (auto bufferPair : buffers) {const Stream *stream = bufferPair.first;StreamConfiguration const &cfg = stream->configuration();auto start = std::chrono::high_resolution_clock::now();auto it = mapped_buffers_.find(bufferPair.second);if (it == mapped_buffers_.end())throw std::runtime_error("failed to identify queue request buffer");libcamera::Span<uint8_t> buffer = it->second[0];uint8_t *ptr = (uint8_t *)buffer.data();cv::Mat image(cfg.size.height, cfg.size.width, CV_8UC1, ptr, cfg.stride);int font = cv::FONT_HERSHEY_SIMPLEX;std::string text = "Framerate: " + std::to_string(framerate);double adjusted_scale_ = 1.0 * cfg.size.width / 1200;double adjusted_thickness_ = std::max(2 * cfg.size.width / 700, 1u);int baseline = 0;cv::Size size = cv::getTextSize(text, font, adjusted_scale_, adjusted_thickness_, &baseline);int bg_ = 0;int fg_ = 255;double alpha_ = 0.3;// Can't find a handy "draw rectangle with alpha" function...for (int y = 0; y < size.height + baseline; y++, ptr += cfg.stride){for (int x = 0; x < size.width; x++)ptr[x] = bg_ * alpha_ + (1 - alpha_) * ptr[x];}cv::putText(image, text, cv::Point(0, size.height), font, adjusted_scale_, fg_, adjusted_thickness_, 0);auto stop = std::chrono::high_resolution_clock::now();auto duration = std::chrono::duration_cast<std::chrono::microseconds>(stop - start);if (mmapTimes.size() > 30){std::cout << std::reduce(mmapTimes.begin(), mmapTimes.end()) / mmapTimes.size() << "\n";mmapTimes.clear();}mmapTimes.push_back(duration.count());int fd = bufferPair.second->planes()[0].fd.get();}/* Re-queue the Request to the camera. */request->reuse(Request::ReuseBuffers);cameras[0]->queueRequest(request);}Code:
static void processRequest(Request *request){float framerate = 0;auto ts = request->metadata().get(controls::SensorTimestamp);uint64_t timestamp = ts ? *ts : request->buffers().begin()->second->metadata().timestamp;if (last_timestamp_ == 0 || last_timestamp_ == timestamp)framerate = 0;elseframerate = 1e9 / (timestamp - last_timestamp_);last_timestamp_ = timestamp;const Request::BufferMap &buffers = request->buffers();for (auto bufferPair : buffers) {const Stream *stream = bufferPair.first;StreamConfiguration const &cfg = stream->configuration();auto start = std::chrono::high_resolution_clock::now(); FrameBuffer *buffer = bufferPair.second; int fd = buffer->planes()[0].fd.get(); uint8_t *ptr = static_cast<uint8_t *>(mmap(NULL, buffer->planes()[0].length, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)); cv::Mat image(cfg.size.height, cfg.size.width, CV_8UC1, ptr, cfg.stride); int font = cv::FONT_HERSHEY_SIMPLEX;std::string text = "Framerate: " + std::to_string(framerate);double adjusted_scale_ = 1.0 * cfg.size.width / 1200;double adjusted_thickness_ = std::max(2 * cfg.size.width / 700, 1u);int baseline = 0;cv::Size size = cv::getTextSize(text, font, adjusted_scale_, adjusted_thickness_, &baseline);int bg_ = 0;int fg_ = 255;double alpha_ = 0.3;// Can't find a handy "draw rectangle with alpha" function...for (int y = 0; y < size.height + baseline; y++, ptr += cfg.stride){for (int x = 0; x < size.width; x++)ptr[x] = bg_ * alpha_ + (1 - alpha_) * ptr[x];}cv::putText(image, text, cv::Point(0, size.height), font, adjusted_scale_, fg_, adjusted_thickness_, 0);auto stop = std::chrono::high_resolution_clock::now();auto duration = std::chrono::duration_cast<std::chrono::microseconds>(stop - start);if (mmapTimes.size() > 30){std::cout << std::reduce(mmapTimes.begin(), mmapTimes.end()) / mmapTimes.size() << "\n";mmapTimes.clear();}mmapTimes.push_back(duration.count());}/* Re-queue the Request to the camera. */request->reuse(Request::ReuseBuffers);camera->queueRequest(request);}Statistics: Posted by peytonicmaster — Thu Feb 08, 2024 7:30 am