Bug 79778 - Flash: Very high latency
Summary: Flash: Very high latency
Alias: None
Product: PulseAudio
Classification: Unclassified
Component: alsa (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: pulseaudio-bugs
QA Contact: pulseaudio-bugs
Depends on:
Reported: 2014-06-07 18:33 UTC by trondsg+bugzilla+freedesktop
Modified: 2018-07-30 09:39 UTC (History)
2 users (show)

See Also:
i915 platform:
i915 features:


Description trondsg+bugzilla+freedesktop 2014-06-07 18:33:52 UTC
Flash audio has very high latency (400 ms +) when played through PulseAudio.

Play/pause on youtube to notice the time it takes until the change goes into effect.

$uname -a
Linux ubuntu-studio 3.13.0-29-lowlatency #53-Ubuntu SMP PREEMPT Wed Jun 4 21:27:51 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

pulseaudio package version: 1:4.0-0ubuntu11
Comment 1 Raymond 2014-06-08 05:03:26 UTC
any reason to use pulseaudio instead of jackd/alss if you want low latency around 5ms to 10ms ?

the default process time of pulseaudio is already 20ms when pulseaudio using a two seconds buffer
Comment 2 trondsg+bugzilla+freedesktop 2014-06-13 16:06:40 UTC
I'd be highly satisfied with a latency of 40 ms. Unfortunately the latency in flash is in the order of 300 to 500 ms. So closer to half a second.

I can explain why this is not ok, but I don't think I should have to.
Comment 3 David Henningsson 2014-09-01 07:07:00 UTC
Flash is difficult because it's not open source, we can't analyze and fix bugs in it. So this is probably a flash bug.

But anyway, there was a patch we recently applied to GIT head (see bug https://bugs.freedesktop.org/show_bug.cgi?id=66962 ) that could affect how Flash behaves, could you test it and see if it helps?
Comment 4 trondsg+bugzilla+freedesktop 2014-09-01 16:47:05 UTC
I'm not sure I want to fiddle around with recompilation as I'm afraid I'll break something. Currently I have acceptable latency by setting PULSE_AUDIO_MSEC=75 before running firefox.
Comment 5 trondsg+bugzilla+freedesktop 2014-09-01 17:06:29 UTC
Just to add, the thing that breaks every time I fiddle with audio is the volume control in the indicator plugin. Volume changes are delayed ~400 ms. Bug 48307.

Also, if setting PULSE_AUDIO_MSEC globally it sometimes (not sure if it is computer dependent) causes regular glitches in other applications, even when set to very high values (500ms). Is this a bug?
Comment 6 GitLab Migration User 2018-07-30 09:39:03 UTC
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/issues/75.

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