Coursera video loses audio or freezes randomly in between




Audio/Video: Playback
3 years ago
2 years ago


(Reporter: rpganesshkumar, Unassigned, NeedInfo)


38 Branch

Firefox Tracking Flags

(Not tracked)




3 years ago
User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:38.0) Gecko/20100101 Firefox/38.0
Build ID: 20150525141253

Steps to reproduce:

Watch videos ( and

Moreover, there is  a separate thread in the course which lists problems faced by lot of students ( 

This is a concern to firefox community because all the issues are faced by firefox users and not by any other browsers

Actual results:

Video loses the audio or freezes

Expected results:

Video should have played perfectly

Comment 1

3 years ago
Not looking for immediate solution. I am looking for a way to debug this issue. My question here are
* What all information is required (to be collected from students who face the issue) to pinpoint the root cause.
* Steps on how students can collect the required info (for example: User Agent)
Flags: needinfo?(rpganesshkumar)

Comment 2

3 years ago
Does it happen only for a platform?
Component: Untriaged → Video/Audio
Product: Firefox → Core

Comment 3

2 years ago
Happens lately although it didn't happen when and media.fragmented-mp4.ffmpeg.enabled were disabled.
Component: Audio/Video → Audio/Video: Playback
Might be better since 42 when MSE got rewritten.
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