Program Listing for File v4l2_video_capture.hpp

            

            
/*
* SPDX-FileCopyrightText: Copyright (c) 2023-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

#ifndef INCLUDE_HOLOSCAN_OPERATORS_V4L2_VIDEO_CAPTURE_V4L2_VIDEO_CAPTURE_HPP
#define INCLUDE_HOLOSCAN_OPERATORS_V4L2_VIDEO_CAPTURE_V4L2_VIDEO_CAPTURE_HPP

#include <linux/videodev2.h>

#include <list>
#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "holoscan/core/operator.hpp"

namespace holoscan::ops {

class GxfFormat;

class V4L2VideoCaptureOp : public Operator {
 public:
  HOLOSCAN_OPERATOR_FORWARD_ARGS(V4L2VideoCaptureOp)

  V4L2VideoCaptureOp() = default;

  void setup(OperatorSpec& spec) override;
  void start() override;
  void initialize() override;
  void compute([[maybe_unused]] InputContext& op_input, OutputContext& op_output,
               ExecutionContext& context) override;
  void stop() override;

  using FormatListItem = std::pair<uint32_t, std::shared_ptr<GxfFormat>>;
  using FormatList = std::list<FormatListItem>;
  typedef void (*ConverterFunc)(const void* in, void* rgba, size_t width, size_t height);

 private:
  Parameter<std::shared_ptr<Allocator>> allocator_;
  Parameter<std::string> device_;
  Parameter<uint32_t> width_;
  Parameter<uint32_t> height_;
  Parameter<float> frame_rate_;
  Parameter<uint32_t> num_buffers_;
  Parameter<std::string> pixel_format_;
  Parameter<bool> pass_through_;
  Parameter<uint32_t> exposure_time_;
  Parameter<uint32_t> gain_;

  void v4l2_initialize();
  void v4l2_request_buffers();
  void v4l2_check_formats();
  void v4l2_get_format();
  void v4l2_set_format();
  bool v4l2_camera_supports_control(int cid, const char* control_name);
  void v4l2_set_camera_control(v4l2_control control, const char* control_name, bool warn);
  void v4l2_set_camera_settings();
  void v4l2_start();
  void v4l2_read_buffer(v4l2_buffer& buf);

  nvidia::gxf::MemoryStorageType memory_storage_type_;
  enum v4l2_memory capture_memory_method_;

  struct Buffer {
    void* ptr;
    size_t length;
  };
  std::vector<Buffer> buffers_;
  int fd_ = -1;

  v4l2_fmtdesc format_desc_{};
  v4l2_format format_{};
  bool supports_frame_rate_ = false;
  uint32_t frame_rate_denominator_use_{1};
  uint32_t frame_rate_numerator_use_{1};

  FormatList::const_iterator v4l2_to_gxf_format_;

  ConverterFunc converter_{nullptr};
};

}  // namespace holoscan::ops

#endif/* INCLUDE_HOLOSCAN_OPERATORS_V4L2_VIDEO_CAPTURE_V4L2_VIDEO_CAPTURE_HPP */