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learningequality / ka-lite

KA Lite: lightweight web server for serving core Khan Academy content (videos and exercises) without needing internet connectivity
https://learningequality.org/ka-lite/
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206 server response for mp4 files on Ubuntu #5384

Closed radinamatic closed 7 years ago

radinamatic commented 7 years ago

Summary

I've been concentrating on subtitles lately, that I just now realized that videos are not actually playing neither in FF nor in Chromium on Ubuntu. They apparently load and one can advance by clicking on the progress slide-bar, but video does not reproduce.

System information

Traceback or relevant snippet from server.log

Only one warn in the console, but I can't see the relevance:

VIDEOJS: WARN: Calling addRemoteTextTrack without explicitly setting the "manualCleanup" parameter to `true` is deprecated and default to `false` in future version of video.js

Servers response is 206 partial content, might be the reason?

How to reproduce

  1. Install 0.17b4
  2. Download some videos

Screenshots

FF: virtualbox_ubuntu 16 10_17_01_2017_14_23_43

Chromium: virtualbox_ubuntu 16 10_17_01_2017_14_22_23

Real-life consequences (anything community should be aware, for instance how it affects your deployment)

Troubling, to say the least... 🤔 @benjaoming I'm tagging this release-blocker until further notice! I'll try to replicate in other Linux VMs asap.

radinamatic commented 7 years ago

VM Gnome Ubuntu 16.10, same issue:

FF: virtualbox_gubuntu_17_01_2017_14_52_28

Chrome: virtualbox_gubuntu_17_01_2017_14_50_35

benjaoming commented 7 years ago

@radinamatic and you've installed the mp4 video codecs?

http://ka-lite.readthedocs.io/en/develop/installguide/system_requirements.html#video-playback

benjaoming commented 7 years ago

Unable to reproduce both with Cherrypy and Django development server.

radinamatic commented 7 years ago

Weird, I just opened an older VM with Ubuntu 15.10 where I had 0.17.b4 installed 2 weeks ago, but was having the left-aligned subs in Firefox 47 - subs are still on left, but the video is playing:

virtualbox_ubuntu15 10-0 17b4

I'm going to upgrade FF to 50 and see what happens...

radinamatic commented 7 years ago

@benjaoming Yes, as noted above, Ubuntu restricted extras are installed, but that was never required in Chrome for correct video playback.

benjaoming commented 7 years ago

@radinamatic does installing it change, though? Chrome might have switched to using native system libraries?

radinamatic commented 7 years ago

AFAIK Ubuntu restricted extras have always been required only by FF, because of some licensing issues that Chrome does not have. And those codecs were installed prior to KA Lite on this VM.

Anyway, upgrading FF to 50 did not bring the issue here, so I'm unable to repro what I reported initially on this third VM - 206 response is present, but videos play OK:

virtualbox_ubuntu15 10-0 17b4-2

radinamatic commented 7 years ago

I've installed a completely new Ubuntu 15.10 VM on the same OSX host as the original issue, and the problem persists. Since I'm unable to reproduce it on my home MiniMac as a host (post above), leads me to believe this might have something to do with the host itself. 🤔

I'll make one more run at it with Ubuntu host just to cover all basis, and we'll take it from there...

benjaoming commented 7 years ago

Thanks @radinamatic - will keep fingers crossed that it's your host :) Try ensuring that video drivers for the VM are installed?

radinamatic commented 7 years ago

Closing this as it seems to be limited to guest VMs on only one of three host machines where I've tested it.