Backend Server

Overview

Flask is used as the backend server for creating APIs and processing videos on backend.

APIs

1. /api :

   • Type : GET, POST
   • Input : None
   • Purpose : Render flask home
   • Output : Flask home HTML

2. /api/postvideo :

   • Type : POST
   • Input : Video File
   • Purpose : To save video file recieved from front end
   • Output : Success/Error Status

3. /api/getframe/filename :

   • Type : GET
   • Input : Video file name
   • Purpose : To send frame of video to frontend
   • Output : Frame of vide

4. /api/postparameters :

   • Type : POST
   • Input : Parameters corresponding to different violation principles
   • Purpose : To send parameters to backend which will be used in processing
   • Output : Success/Error Status

5. /api/imageslist/feature :

   • Type : GET
   • Input : Featue Type
   • Purpose : Depending on feature selected, return list of images corresponding to that feature
   • Output : List of images which can later be retrieved by frontend

6. /api/getimage :

   • Type : Get
   • Input : None
   • Purpose : Return a sample iamge
   • Output : Sample Image

7. /api/getvideo/feature :

   • Type : GET
   • Input : Feature Type
   • Purpose : Get partial response of video in chunks
   • Output : Partial Response

Functions

1. cleanMedia() :

   • Input : None
   • Purpose : To clean all the media files from previous processing
   • Output : None

2. createDirectories() :

   • Input : None
   • Purpose : To create feature directories for runtime purposes
   • Output : None

Modules

1. video_stream

   • In house implemented video streaming server.
   • Instead of returning entire video at once, it is returned in chunks which are rendered on browser

2. cv2:

   • Opencv helps in retrieving frame from a video which user can draw on