887228 - Sound stops when video is played at 0.25x rate

Status: RESOLVED WORKSFORME

(Toolkit :: Video/Audio Controls, defect)

Description

[Cornel Ionce [:noni] [Hubs QA]]

Steps to reproduce:
1. Launch Firefox.
2. Open about:config and set media.webm.enabled to false.
3. Open the Add-ons Manager to the Plugins section and disable Flash.
4. Restart Firefox.
5. Load Youtube's HTML Trial and click "Join the HTML5 trial".
6. Go yo Youtube.com and load a video.
7. Change the play rate to 0.25x.

Expected result:
The video and sound are played at the selected rate.

Actual result:
The video is played without sound. 

Note:
Sound starts to play if the volume is changed (or mute/unmute).


Tested on Firefox 23 Beta 1 (build ID: 20130625125232)
User Agents:
Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20100101 Firefox/23.0
Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20100101 Firefox/23.0

Graphics: NVIDIA GeForce GT 620
Driver Version: 9.18.13.1106

Comment 1

[Paul Adenot (:padenot)]

This is expected, per spec [1]:

> When the effective playback rate is so low or so high that the user agent cannot play audio 
> usefully, the corresponding audio must also be muted.

We have determined that at 0.25x, the audio is of poor quality, and it would be better to mute it.

What would not be expected is that the sound comes back when adjusting the volume or on mute/unmute, but I can't reproduce (or it is fixed in the Nightly build, Linux I'm using).

[1]: http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#media-playback

Comment 2

[u279076]

Cornel, can you please investigate this further along the lines of what Paul mentions in comment 1?

Comment 3

[Cornel Ionce [:noni] [Hubs QA]]

I have also verified on latest Nightly (build ID: 20130626031100) and the issue is fixed. 

If the rate is 0.25x, the audio is disabled and it cannot be enabled even if you adjust the volume or mute/unmute (nothing happens).

User Agents:
Mozilla/5.0 (Windows NT 6.2; WOW64; rv:25.0) Gecko/20130626 Firefox/25.0
Mozilla/5.0 (Windows NT 6.1; rv:25.0) Gecko/20130626 Firefox/25.0


Should I log an enhancement for the fact that you can adjust the volume even if the audio is disabled? I think this can be quite confusing for a regular user.

Comment 4

[Paul Adenot (:padenot)]

Please file it and cc :jaws and me. He can decide what we want to do in this case.

I guess we can close this, now.

Thanks!

Comment 5

[Timothy B. Terriberry (:derf)]

(In reply to Paul Adenot (:padenot) from comment #1)
> What would not be expected is that the sound comes back when adjusting the
> volume or on mute/unmute, but I can't reproduce (or it is fixed in the
> Nightly build, Linux I'm using).

This was fixed in bug 872925.