1135052 - [Youtube] Clicking Next/Previous in HTML5 Full screen will sometimes NOT auto play the video

Status: RESOLVED WORKSFORME

(Core :: Audio/Video, defect)

Description

[[SV Manager] Florin Mezei, QA (:FlorinMezei)]

Reproducible with: 
- Firefox 36 RC - BuildID: 20150219174507

NOT reproducible on:
- latest Firefox 37 Aurora - BuildID: 20150220004124 - HTML5 player crashes when clicking next (will file separately)
- latest Firefox 38 Nightly - BuildID: 20150220030202 - HTML5 player crashes when clicking next (will file separately)

Reproducible on: Mac OS X 10.9.5 (Retina)

NOT reproducible on: Windows 7 x64, Windows 8.1 x86, Ubuntu 14.04 x64

Steps to reproduce:
1. Open Firefox and go to https://www.youtube.com/html5 and click "Request the HTML5 player".
2. Open a list o videos e.g. https://www.youtube.com/watch?v=y6Sxv-sUYtM&list=RDy6Sxv-sUYtM#t=1
3. Enter fullscreen.
4. Seek forward and wait for ~5-6 seconds to pass then click the Next button (repeat step a few times if not reproducible on first try).

Expected results:
Next video starts to play automatically.

Actual results:
Sometimes next video is loaded but does not start to play automatically. The same happens when clicking Previous or opening the video list in full screen and selecting another video.

Notes:
- the issue reproduces often with scenario above, and sometimes when just clicking Next/Previous
- the issue does not show when NOT in full screen
- the issue does not show with Flash
- this is not a recent regression as the issue also reproduces in Firefox 32.0.3

Comment 1

[[SV Manager] Florin Mezei, QA (:FlorinMezei)]

I've tried this over the past couple of days on Mac OS X 10.9.5, but I was no longer able to reproduce the issue with:
- Firefox 37 Beta 2 & 3
- latest Firefox 38 Aurora
- latest Firefox 39 Nightly

What's weirder is that I can no longer reproduce this issue on older Nightly builds after October 24th. When I filed the bug, issue was easily reproducible on those builds. Is it possible that something changed on YouTube's side that no longer affects us? 

I tested without being signed in (every video in fullscreen was automatically started in HD) and when signed in, with the setting for automatically loading HD in fullscreen disabled.

Note that bug 1135062 also no longer reproduces.

Comment 2

[[SV Manager] Florin Mezei, QA (:FlorinMezei)]

Closing both this issue and bug 1135062, as both of them no longer reproduce.