Added videos

Author: sevdaimany

videos.ipynb

@@ -0,0 +1,253 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "78d92095",
+   "metadata": {},
+   "source": [
+    "</br><div align=\"center\"> <b> <font size=\"6\" color='red'>Reading and Writing Videos</font></b> </div>\n",
+    "</br>"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "f1711405",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import cv2\n",
+    "import matplotlib.pyplot as plt\n",
+    "import numpy as np\n",
+    "from IPython.display import Video"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "911afb2f",
+   "metadata": {},
+   "source": [
+    "</br><div align=\"center\"> <b> <font size=\"5\" color='red'>Reading Video From a File</font></b> </div>\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "408c4499",
+   "metadata": {},
+   "source": [
+    "<div align=\"center\"> <b> <font size=\"3\" color='green'>VideoCapture(path, apiPreference)</font></b> </div>\n",
+    "<b>path:</b> video path + video name <br>\n",
+    "<b>apiPreference:</b> will be explained later, default value is nothing<br>"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "id": "a5743f18",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "vid_capture = cv2.VideoCapture('./videos/traffic.mp4')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "6702b4cd",
+   "metadata": {},
+   "source": [
+    "Usefull method of VideoCapture:</br>\n",
+    "<b>isOpened():</b> return a boolean that indicates whether or not the video stream is valid <br>\n",
+    "<b>read():</b> read frame sequentially. This method returns a tuple, where the first element is a boolean and the next element is the actual video frame. <br>\n",
+    "<b>release():</b>release vid_capture object</br>\n",
+    "<b>get():</b> retrieve important metadata associated with the video stream \n",
+    " - get(3): frame width\n",
+    " - get(4): frame height\n",
+    " - get(5): video frame rate (fps)\n",
+    " - get(7): video frame count"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "id": "2f9c630c",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Frame Rate :  29 frames per second\n",
+      "Frame count :  599.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "if (vid_capture.isOpened() == False):\n",
+    "    print(\"Error opening the video file\")\n",
+    "else:\n",
+    "    fps = int(vid_capture.get(5))\n",
+    "    print(\"Frame Rate : \",fps,\"frames per second\")\n",
+    "    frame_count = vid_capture.get(7)\n",
+    "    print(\"Frame count : \", frame_count)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "2c4486a8",
+   "metadata": {
+    "scrolled": false
+   },
+   "outputs": [],
+   "source": [
+    "vid_capture = cv2.VideoCapture('./videos/traffic.mp4')\n",
+    "ind_frame = 0\n",
+    "# ind_pic = 0\n",
+    "# fig, axes = plt.subplots(nrows=1, ncols=6, figsize=(20,20))\n",
+    "# ret, frame = vid_capture.read()\n",
+    "while vid_capture.isOpened():\n",
+    "    ret, frame = vid_capture.read()\n",
+    "    if not ret:\n",
+    "        break\n",
+    "#     if ind_frame%100==0:\n",
+    "#         axes[ind_pic].set_title(str(ind_frame))\n",
+    "#         axes[ind_pic].imshow(frame)\n",
+    "#         ind_pic+=1\n",
+    "    pic_name = 'traffic_frame/traffic'+str(ind_frame).zfill(3)+'.jpg'\n",
+    "    cv2.imwrite(pic_name, frame)\n",
+    "    ind_frame+=1\n",
+    "vid_capture.release()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "85560405",
+   "metadata": {},
+   "source": [
+    "</br><div align=\"center\"> <b> <font size=\"5\" color='red'>Reading an Image Sequence</font></b> </div>\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "e87c0265",
+   "metadata": {},
+   "source": [
+    "</br><div align=\"center\"> <b> <font size=\"3\" color='green'>VideoCapture(image_sequence)</font></b> </div>"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "fe00a166",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "vid_capture = cv2.VideoCapture('traffic_frame/traffic%03d.jpg')"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "id": "4238de3e",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Frame count :  599.0\n"
+     ]
+    }
+   ],
+   "source": [
+    "frame_count = vid_capture.get(7)\n",
+    "print(\"Frame count : \", frame_count)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "472aa38c",
+   "metadata": {},
+   "source": [
+    "</br><div align=\"center\"> <b> <font size=\"5\" color='red'>Writing videos</font></b> </div>"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "f6b1cd4b",
+   "metadata": {},
+   "source": [
+    "To write a video use following method:\n",
+    "</br><div align=\"center\"> <b> <font size=\"3\" color='green'>VideoWriter(filename, fourcc, fps, frameSize)</font></b> </div>\n",
+    "<b>filename:</b> pathname for the output video file <br>\n",
+    "<b>fourcc:</b> 4-character code of codec, used to compress the frames (fourcc) <br>\n",
+    "<b>fps:</b> frame rate of the created video stream <br>\n",
+    "<b>frameSize:</b> size of the video frames<br>"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "227cc546",
+   "metadata": {},
+   "source": [
+    "<b> about fourcc</b></br>\n",
+    "The video codec specifies how the video stream is compressed. It converts uncompressed video to a compressed format or vice versa. To create AVI or MP4 formats, use the following fourcc specifications:\n",
+    "\n",
+    "AVI: cv2.VideoWriter_fourcc('M','J','P','G')\n",
+    "\n",
+    "MP4: cv2.VideoWriter_fourcc(*'XVID')"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "id": "6540c287",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "vid_capture = cv2.VideoCapture('traffic_frame/traffic%03d.jpg')\n",
+    "frame_size = (int(vid_capture.get(3)),int(vid_capture.get(4)))\n",
+    "# print(frame_size)\n",
+    "output = cv2.VideoWriter('traffic_fast.avi', cv2.VideoWriter_fourcc('M','J','P','G'), 60, frame_size)\n",
+    "while(vid_capture.isOpened()):\n",
+    "    ret, frame = vid_capture.read()\n",
+    "    if ret == True:\n",
+    "        output.write(frame)\n",
+    "    else:\n",
+    "        break\n",
+    "\n",
+    "vid_capture.release()\n",
+    "output.release()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "fda40d13",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.8.2"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}