multi-connection WEBM retrieval flaky on Linux

Assigned to



Audio/Video: Playback
a year ago
5 months ago


(Reporter: N. de Jonge, Assigned: kaku)


53 Branch

Firefox Tracking Flags

(Not tracked)




a year ago
User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:49.0) Gecko/20100101 Firefox/49.0
Build ID: 20160922183953

Steps to reproduce:

A page embeds fifteen WEBM videos that are all hosted on the same server.

I (re)load the page.

Actual results:

Occasionally one or more video previews do not show up, and/or one or more videos do not play.
Instead these video areas display an error.

Depending on the Firefox version used, the error message is:
"Video playback aborted due to a network error."
"Video format or MIME type is not supported."

I can replicate this with versions 49.0, 51.0b12 and 53.0a1.
Firefox' network monitor shows ~0ms 0 bytes when videos fail to load.

The occasional errors only show up in Linux (Mint).
It does not matter if safe mode is enabled or not.
Chromium on Linux does not have the occasional errors.
Firefox (50.1.0) in Windows (Wine, to be exact; Windows emulator) does not have the occasional errors.

Adding "AddType video/webm .webm" to .htaccess does not fix the occasional errors.

I know a workaround.
Changing network.http.max-connections from 900 to 1 fixes the problem.

- Maybe the server limits simultaneous connections per host, and Firefox for Linux doesn't deal with this properly. Firefox for Windows, and Chromium for Linux do not have the problem.
- Maybe it matters that the videos are large (20MB+).

Expected results:

All videos previews should show up, and all videos should play.


a year ago
Component: Untriaged → Audio/Video: Playback
Product: Firefox → Core
Can you provide a link that reproduces the issue?
Flags: needinfo?(mail)

Comment 2

a year ago
(In reply to Anthony Jones (:kentuckyfriedtakahe, :k17e) from comment #1)
> Can you provide a link that reproduces the issue?

Yes, visit with Firefox on Linux:
You may immediately see that some don't load properly.
Even if they all do, click play on those that seem to be ready.
If all work, reload the page to retry.

Just now I could immediately reproduce the issue here.
"Video playback aborted due to a network error."
Setting network.http.max-persistent-connections-per-server=12 fixes the issue.
Priority: -- → P1

Comment 4

10 months ago
I can also reproduce this in Firefox 53 on Window 10 and OSX 10.12.

Comment 5

10 months ago
Change network.http.max-persistent-connections-per-server does not work for me.


10 months ago
Assignee: nobody → kaku
Ever confirmed: true


10 months ago
See Also: → bug 1361756
Mass change P1->P2 to align with new Mozilla triage process
Priority: P1 → P2


5 months ago
Flags: needinfo?(mail)
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