1148377 - [Youtube][HTML5] Video no longer works when seeking after an ad is played at the end

Status: RESOLVED INVALID

(Core :: Audio/Video, defect, P1)

Description

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

Reproducible with: 
- Firefox 37 RC2 - BuildID: 20150326190726
- latest Firefox 38 Aurora - BuildID: 20150327004016
- latest Firefox 39 Nightly - BuildID: 20150326030212

Reproducible on: Windows 7 x64 

Steps to reproduce:
1. Open Firefox with a fresh profile and go to: https://www.youtube.com/watch?v=mCB5uqAZNxQ.
2. Seek close to the end of the video and wait for it to finish.
3. When video ends an ad should be presented (if it's not presented then restart from step #1).
4. Skip the ad, and then seek inside the same video.

Expected results:
Video starts playing from where the user seeked.

Actual results:
Video does not start. The image is black, the seek bar does not move, and the pause button is not functional (clicking it does nothing).

Notes:
- the end result is similar to bug 1142992
- the key to getting this issue seems to be getting the ad at the end of the video - if the ad does not show then the issue does not appear (the URL used here always seems to generate an ad at the end of the video)
- about:media displays (in DevEdition):
https://www.youtube.com/watch?v=mCB5uqAZNxQ
	
	currentTime: 0

Comment 1

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

Forgot to mention, but this is not a recent regression as I get the issue to show in Firefox 33.1.1 with HTML5 player set for YouTube (from https://www.youtube.com/html5).

Comment 2

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

[Tracking Requested - why for this release]: I think this should be tracked together with bug 1142992, as it's potentially the same issue but triggered by different scenarios.

Comment 3

[Liz Henry (:lizzard) (relman/hg->git project)]

Tracking for 39 and 40. Though this isn't a recent regression it sounds like it is frequently reproducible and has a bad impact.

Comment 4

[Lawrence Mandel [:lmandel] (use needinfo)]

I'm not tracking for 37 as we've shipped this issue for a few releases. I am tracking for 38 as we need to determine if this is a problem when playing with MSE or only HTML5 video.

ni Anthony

Comment 5

[Jean-Yves Avenard [:jya]]

Is that something you can only reproduce with that particular video?

This video is known to have a few encoding issues (segments aren't properly adjactents with 33ms gaps between them). I don't believe such videos are commonly seen on youtube.

This would lower how likely this issue is to occur.

Comment 6

[Jean-Yves Avenard [:jya]]

I never managed to get the ad at the end of the video.
I only ever sees the ad when the video starts. When I then skip the starting ad, seek close to the end, I see the screen showing that it will jump to the next video.

When you say seek next to the end of the video, what time precisely? that video is 10:48 long.

Do you seek 10s from the end, 20 ?

Comment 7

[Jean-Yves Avenard [:jya]]

This is a youtube bug.

When the ad plays at the end, the mediasource element is removed from the HTMLMediaElement. There's nothing left to play anymore.

I can reproduce the exact same behaviour in Chrome 39.

Comment 8

[Jean-Yves Avenard [:jya]]

There is nothing to fix. So untracking...