I'm using 64bit Debian Jessie. Yesterday I pulled an update of Iceweasel using apt-get update and apt-get upgrade. For my surprise now its no longer called like that and instead it has the name Firefox ESR. The name is not the issue here (obviously). Right after that I started the freshly updated web browser and found that:

  • Videos played in a Flash player stutter - even when fully loaded the video's sound and image stutter throughout the whole thing. I've looked for a solution but nothing worked. Some suggested that it will get fixed by disabling hardware acceleration (well, it didn't), other suggested that the problem comes from the protective mode. The second I found quite interesting and looked more into it. I managed to find dom.ipc.plugins.flash.disable-protected-mode in the about:config which supposedly did that. Nothing changed (I also restarted the browser in case the change requires that). This issue is not only happening with video content but also with sound-only content such as streaming radio and/or music.

  • Controls of the YouTube's HTML5 player response really slowly - I actually checked HTML5 video playback on several other streaming web sites and while it was not that bad there were still some noticeable delay in the response. With controls I mean right click on the player for its context menu, pausing/unpausing, regulating the volume, opening the quality menu, going in and out of fullscreen mode etc. The video and sound itself works without any issues.

Any ideas how to fix these issues?

EDIT: I have also refreshed Firefox but it didn't fix the problems mentioned above.

EDIT 2: Creating a new profile also didn't change a thing.

  • Does it happen only with the existing iceweasel profile, or have you tried a new fresh profile as well?
    – Tim
    Commented Sep 17, 2016 at 12:50
  • I forgot to mention that I refreshed Firefox after the update (thought this might fix my problems). Commented Sep 17, 2016 at 13:03
  • Can you try creating a new profile by invoking a firefox binary with -profilemanager parameter and running it? The "Refresh" feature has a little bit different behaviour.
    – Tim
    Commented Sep 17, 2016 at 13:12
  • Thanks for the tip. I did create a new profile but the problems are still there. :-/ Commented Sep 17, 2016 at 13:44

2 Answers 2


This is just a partial answer (I will try to update it if I don't forget and if I find a solution to all the listed problems) concerning the stutter of Flash videos - the problem was coming from PulseAudio. I found the solution while working my way through the Debian and Arch wikis.

I added/changed the following settings in /etc/pulse/daemon.conf:

# For stutter in Flash videos (perhaps also the additional settings at the end have affect this)
high-priority = no
nice-level = -1
realtime-scheduling = yes
realtime-priority = 5
flat-volumes = no
resample-method = speex-float-1

# For distortion and high CPU usage in Wine and Skype
default-fragments = 25
default-fragment-size-msec = 25
default-sample-rate = 48000

As for the HTML5 player I have recently updated my 38.x ESR Firefox to 45.x ESR and started to have similar problems. What helped was disabling all four media.mediasource.* entries in about:config thus forcing the player to use older video format. It works much faster now, though not as fast as it worked in FF 38. Also full video buffering works again. You can also try setting both full-screen-api.transition-duration.* to 0 for decreasing fullscreen switching delay.

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