const fs = require('fs');

fifo = fs.createReadStream(process.argv[2], { highWaterMark: 4*1024**2, });

let t0 = Date.now();
fifo.on('readable', () => {
  const chunk = fifo.read(1024 ** 2);
  if (chunk !== null) {
    let t1 = Date.now();
    process.stdout.write(`${(t1 - t0)/1000.}s, ${1000./(t1 - t0)}fpsn`);
    t0 = t1;
  }

});

fifo.on('end', () => {
  process.stdout.write('end');
});

import sys
import numpy as np

im = np.random.randint(0, 255, size=(1024, 1024)).astype(np.uint8).ravel()

with open(sys.argv[1], 'wb') as f:
    while True:
        f.write(im.tobytes())
        f.flush()

import sys
import numpy as np
import time

l = 1024 ** 2
t0 = time.time()
with open(sys.argv[1], 'rb') as f:
    while True:
        im = f.read(l)
        t1 = time.time()
        print('{}s, {}fps'.format(t1 - t0, 1/(t1 - t0)))
        t0 = t1

mkfifo /tmp/video; python producer.py /tmp/video & node reader.js /tmp/video

mkfifo /tmp/video; python producer.py /tmp/video & python reader.py /tmp/video