{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "import cv2\n",
    "import time, os\n",
    "import threading\n",
    "import numpy as np\n",
    "import multiprocessing as mp\n",
    "import matplotlib.pyplot as plt\n",
    "\n",
    "from situtils import FPSTimes"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "class VideoWriter(FPSTimes):\n",
    "    # precise timing https://stackoverflow.com/questions/42565297/precise-loop-timing-in-python\n",
    "    \n",
    "    default_cfg = {\n",
    "        'fps': 20,\n",
    "        'file_path': 'test_video.avi',\n",
    "    }\n",
    "    \n",
    "    def __init__(self, status, video_stream, cfg):\n",
    "        super(VideoWriter, self).__init__()\n",
    "        \n",
    "        self.cfg = cfg\n",
    "        self.video_stream = video_stream  # cv2 video stream\n",
    "        self.stopped = False\n",
    "        self.status = status\n",
    "        \n",
    "        fourcc = cv2.VideoWriter_fourcc(*'XVID')\n",
    "        res_x, res_y = int(video_stream.stream.get(3)), int(video_stream.stream.get(4))\n",
    "        self.out = cv2.VideoWriter(cfg['file_path'], fourcc, cfg['fps'], (res_x, res_y))\n",
    "\n",
    "    @property\n",
    "    def latency(self):\n",
    "        return 1.0/self.cfg['fps']\n",
    "        \n",
    "    def start(self):\n",
    "        self._th = threading.Thread(target=self.update, args=())\n",
    "        self._th.start()\n",
    "    \n",
    "    def stop(self):\n",
    "        self.stopped = True\n",
    "        time.sleep(0.2)   # wait until device is released\n",
    "        self._th.join()\n",
    "        print('Video writer stopped')\n",
    "        \n",
    "    def update(self):\n",
    "        next_frame = time.time() + self.latency\n",
    "        \n",
    "        while not self.stopped:\n",
    "            if self.status.value == 2:\n",
    "                if time.time() < next_frame:\n",
    "                    continue  # TODO sleep here?\n",
    "\n",
    "                #frame = self.video_stream.read()\n",
    "                frame = self.video_stream.frame_with_infos\n",
    "                if frame is not None:\n",
    "                    self.count()  # count FPS\n",
    "                    self.out.write(frame)\n",
    "\n",
    "                    frames_missed = np.floor((time.time() - next_frame) * self.cfg['fps'])\n",
    "                    next_frame += self.latency * frames_missed + self.latency\n",
    "            else:\n",
    "                time.sleep(0.05)\n",
    "            \n",
    "        self.out.release()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Testing video recording"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Webcam stream 960.0:720.0 at 20.00 FPS started\n",
      "Camera released\n",
      "Video writer stopped\n"
     ]
    }
   ],
   "source": [
    "#import nbimporter\n",
    "#from camera import WebcamStream\n",
    "\n",
    "# let's use a webcam stream\n",
    "vs = WebcamStream(WebcamStream.default_cfg)\n",
    "vs.start()  # stream runs in a separate thread\n",
    "\n",
    "# recording status: 1 - idle, 2 - recording\n",
    "status = mp.Value('i', 1)\n",
    "\n",
    "# start/stop recording by pressing 's'\n",
    "vw = VideoWriter(status, vs, VideoWriter.default_cfg)\n",
    "vw.start()\n",
    "\n",
    "try:\n",
    "    while True:\n",
    "        frame = vs.read()\n",
    "        if frame is not None:\n",
    "            color = (127, 255, 0) if status.value == 1 else (0, 0, 255)\n",
    "            frame = cv2.circle(frame, (20, 20), 15, color, -1)\n",
    "            cv2.imshow('Webcam', frame)\n",
    "\n",
    "        k = cv2.waitKey(33)\n",
    "        if k == ord('q'):\n",
    "            break\n",
    "            \n",
    "        if k == ord('s'):\n",
    "            status.value = 2 if status.value == 1 else 1\n",
    "finally:\n",
    "    cv2.destroyAllWindows()\n",
    "    vs.stop(), vw.stop()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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