title: Opencv VideoCapture always returns false on Heroku
body: <p>I'm using the following code to open a video stream:</p>
  <pre><code>import cv2
  video = cv2.VideoCapture()
  video.open(&quot;some_m3u8_link&quot;)
  success, image = video.read()
  </code></pre>
  <p>However, even if the code works as intended locally, on Heroku <code>success</code> is always false.</p>
  <p>I'm using cedar-14 stack with the following buildpacks:</p>
  <blockquote>
  <p>heroku/python</p>
  <p><a href="https://github.com/jonathanong/heroku-buildpack-ffmpeg-latest.git" rel="nofollow noreferrer">https://github.com/jonathanong/heroku-buildpack-ffmpeg-latest.git</a></p>
  </blockquote>
  <p>(I tried several buildpack options for ffmpeg)</p>
  <p>Running <code>ffmpeg --version</code> on heroku instance will return <code>ffmpeg version 4.0-static https://johnvansickle.com/ffmpeg/</code></p>
  <p>Is there any setting/configuration I missed in order to make it work on deployment? Thank you!</p>
  <p>Later edit: I tried several links for &quot;some_m3u8_link&quot; including from twitch and other streaming services (including traffic streaming li
  An example for reproducing:</p>
  <pre><code>python -c &quot;import cv2; video=cv2.VideoCapture(); video.open('https://hddn01.skylinewebcams.com/live.m3u8?a=5tm6kfqrhqbpblan9j5d4bmua4'); success, image = video.read(); print(success)&quot;
  </code></pre>
  <p>Returns True on local machine and False on Heroku.</p>
  <p>(the link is taken from <a href="https://www.skylinewebcams.com/en/webcam/malta/malta/traffic/traffic-cam14.html" rel="nofollow noreferrer">here</a>)</p>