CV2 create blurry videos

Question

import numpy as np
import cv2
size = 80,80
duration = 2
fps = 25
out = cv2.VideoWriter('output.avi', cv2.VideoWriter_fourcc(*'X264'), fps, size)
for l in range(fps * duration):
    data = np.zeros( (80,80,3), dtype=np.uint8 )
    for k in range(80):
        data[40][k]=[255,0,0]
    out.write(data)
out.release()

When I want to create an video from an array of pixels (in the example a line, but I need to create more complex images) the result is very blurry and difficult to read.

Is there a specific format to create smooth pixels with cv2 or I need another video library?

For the input, it's an array 80*80 like in this code but with my data And I get the second image when converting to video

Imput

Output (same with .avi or .mp4)