compute_flow.py

import cv2
import base64
import numpy as np
from tqdm import tqdm
import os

from flow_utils import RAFT_estimate_flow
import h5py

import argparse

def main(args):
  W, H = args.width, args.height
  # Open the input video file
  input_video = cv2.VideoCapture(args.input_video)

  # Get useful info from the source video
  fps = int(input_video.get(cv2.CAP_PROP_FPS))
  total_frames = int(input_video.get(cv2.CAP_PROP_FRAME_COUNT))

  prev_frame = None

  # create an empty HDF5 file
  with h5py.File(args.output_file, 'w') as f: pass

  # open the file for writing a flow maps into it
  with h5py.File(args.output_file, 'a') as f:
    flow_maps = f.create_dataset('flow_maps', shape=(0, 2, H, W, 2), maxshape=(None, 2, H, W, 2), dtype=np.float16) 

    for ind in tqdm(range(total_frames)):
      # Read the next frame from the input video
      if not input_video.isOpened(): break
      ret, cur_frame = input_video.read()
      if not ret: break

      cur_frame = cv2.resize(cur_frame, (W, H))

      if prev_frame is not None:
        next_flow, prev_flow, occlusion_mask = RAFT_estimate_flow(prev_frame, cur_frame)

        # write data into a file
        flow_maps.resize(ind, axis=0)
        flow_maps[ind-1, 0] = next_flow
        flow_maps[ind-1, 1] = prev_flow

        occlusion_mask = np.clip(occlusion_mask * 0.2 * 255, 0, 255).astype(np.uint8)

        if args.visualize:
          # show the last written frame - useful to catch any issue with the process
          img_show = cv2.hconcat([cur_frame, occlusion_mask])
          cv2.imshow('Out img', img_show)
          if cv2.waitKey(1) & 0xFF == ord('q'): exit() # press Q to close the script while processing

      prev_frame = cur_frame.copy()

  # Release the input and output video files
  input_video.release()

  # Close all windows
  if args.visualize: cv2.destroyAllWindows()

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('-i', '--input_video', help="Path to input video file", required=True)
    parser.add_argument('-o', '--output_file', help="Path to output flow file. Stored in *.h5 format", required=True)
    parser.add_argument('-W', '--width', help='Width of the generated flow maps', default=1024, type=int)
    parser.add_argument('-H', '--height', help='Height of the generated flow maps', default=576, type=int)
    parser.add_argument('-v', '--visualize', action='store_true', default=False, help='Show proceed images and occlusion maps')
    args = parser.parse_args()

    main(args)