CameraFrameSourceOpenCV.h

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#pragma once
 
#include "AudioTools/Video/Video.h"
#include <opencv2/core/core.hpp>
#include <opencv2/videoio/videoio.hpp>
#include <opencv2/imgcodecs/imgcodecs.hpp>
#include <vector>
 
namespace audio_tools {

class CameraFrameSourceOpenCV : public VideoFrameSource {
 public:
  CameraFrameSourceOpenCV() = default;
  CameraFrameSourceOpenCV(int device) : device_index(device) {}

  void setVideoInfo(VideoInfo info) { this->info = info; }

  void setDevice(const char *device) { device_string = device; }

  void setApiPreference(int api) { api_preference = api; }

  void setJpegQuality(int quality) { jpeg_quality = quality; }

  bool begin() {
    bool ok = device_string != nullptr
                  ? cap.open(device_string, api_preference)
                  : cap.open(device_index, api_preference);
    if (!ok) {
      LOGE("CameraFrameSourceOpenCV: could not open capture device");
      return false;
    }
    if (info.width > 0) cap.set(cv::CAP_PROP_FRAME_WIDTH, info.width);
    if (info.height > 0) cap.set(cv::CAP_PROP_FRAME_HEIGHT, info.height);
    if (info.fps > 0) cap.set(cv::CAP_PROP_FPS, info.fps);
 
    info.width = (uint16_t)cap.get(cv::CAP_PROP_FRAME_WIDTH);
    info.height = (uint16_t)cap.get(cv::CAP_PROP_FRAME_HEIGHT);
    float dev_fps = (float)cap.get(cv::CAP_PROP_FPS);
    if (dev_fps > 0) info.fps = dev_fps;
    if (info.format == VideoFormat::UNKNOWN) info.format = VideoFormat::MJPEG;
    return true;
  }

  void end() { cap.release(); }

  const uint8_t *nextFrame(size_t &len) override {
    if (!cap.read(frame) || frame.empty()) {
      len = 0;
      return nullptr;
    }
    if (info.format == VideoFormat::RAW) {
      len = frame.total() * frame.elemSize();
      return frame.data;
    }
    std::vector<int> params{cv::IMWRITE_JPEG_QUALITY, jpeg_quality};
    cv::imencode(".jpg", frame, jpeg_buffer, params);
    len = jpeg_buffer.size();
    return jpeg_buffer.data();
  }

  VideoInfo videoInfo() override { return info; }
 
 protected:
  cv::VideoCapture cap;
  cv::Mat frame;
  std::vector<uint8_t> jpeg_buffer;
  VideoInfo info;
  int device_index = 0;
  const char *device_string = nullptr;
  int api_preference = cv::CAP_ANY;
  int jpeg_quality = 90;
};
 
using CameraFrameSource = CameraFrameSourceOpenCV;
 
}  // namespace audio_tools