1192679 - Video goes out of video audio sync in FF39

Status: RESOLVED DUPLICATE of bug 1168040

(Core :: Audio/Video, defect)

Description

[Anton]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:34.0) Gecko/20100101 Firefox/34.0
Build ID: 20141126041045

Steps to reproduce:

play the following video and note that audio all of a sudden does not match video, way out of sync when download buffering completes http://www.videoproductions.com.au/FF/Anton-0690.png
http://www.videoproductions.com.au/Agi-Kleen/ (play the DrumBuster.mp4)


Actual results:

if watching the above video in FF 36 and earlier, video audio is in perfect sync, I have reverted to FF 34.05 for the moment

if the above video is downloaded to hard disk and then played with FF39, it remains in sync


Expected results:

video and audio should stay in sync from start to finish

issue confirmed by other user at http://forums.mozillazine.org/viewtopic.php?f=9&t=2952839

Comment 1

[Loic]

Are you able to reproduce the issue with a smaller video testcase (because waiting for complete buffering for a 180-MB 720p video is pretty long)?

Comment 2

[Anton]

it works perfect as is in FF 34.05 so I will stick with that for now, thanks

Comment 3

[Anton]

here is a smaller mp4 of less than 30mb
http://www.videoproductions.com.au/video/AHO2009.mp4

Comment 4

[Matthew Gregan [:kinetik]]

(In reply to Anton from comment #3)
> here is a smaller mp4 of less than 30mb
> http://www.videoproductions.com.au/video/AHO2009.mp4

This video is out of sync from the outset in Firefox but fine in Chrome.

I can't reproduce the sync issue with the video in comment 0, but it sounds like it's buffering/timing related as you reported that it plays fine if played from a local file.

I don't think these sync issues are related to bug 1136360/bug 1164966.  This seems like an issue with the MP4 decoder side of things, rather than audio playback.

Comment 5

[Jean-Yves Avenard [:jya]]

This video plays perfectly in sync for me on mac (41 or 42)
On my windows 8 VM, it's very slightly off, but barely noticeable and I'm assuming this is just because I use a VM and there's always a slight latency for audio playback

We didn't handled timestamp offset properly until bug 1168040 (a bug in stagefright) so it would have been broken from 36 onward when we enabled the MP4Reader

Comment 6

[Matthew Gregan [:kinetik]]

Anton, bug 1168040 is fixed in Firefox 41, so could you please try with a beta build (which is currently 41) and let us know if it works for you?

Comment 7

[Anton]

I will try beta 41, thanks

Comment 8

[Anton]

could you point me in the right direction where to find a full installer of beta 41

I tried the following site but the downloaded file from the below site is only 238kb and I don't trust that
https://www.mozilla.org/en-US/firefox/channel/#beta

Comment 9

[Anton]

I found another site https://nightly.mozilla.org/ but now I am confused if I need 32bit or 64bit

my currently installed version is in program files 86 (in other words a 32bit version)

but I have Win7 64bit, so maybe I had the wrong version all along? please instruct

Comment 10

[Jean-Yves Avenard [:jya]]

You can use the 32 bits version as that's what you've been using all this time.

You can get beta there:

https://www.mozilla.org/en-US/firefox/channel/

You may not want to try Nightly yet :)

Comment 11

[Jean-Yves Avenard [:jya]]

oh, the small file is an installer ; it will download the full release.

Comment 12

[Jean-Yves Avenard [:jya]]

the direct link to what you would need is:
https://download.mozilla.org/?product=firefox-beta-stub&os=win&lang=en-US

Comment 13

[Anton]

I can confirm that FF 41 beta has fixed the video issue

however, it has disabled my logitech mouse addon and I can no longer use smooth scroll in webpages
http://www.videoproductions.com.au/FF/logitech.png

Comment 14

[Matthew Gregan [:kinetik]]

(In reply to Anton from comment #13)
> I can confirm that FF 41 beta has fixed the video issue

Thanks for testing! I'll close this as a duplicate of bug 1168040.

> however, it has disabled my logitech mouse addon and I can no longer use
> smooth scroll in webpages
> http://www.videoproductions.com.au/FF/logitech.png

This may be because the addon only claims to work with certain (released?) versions of Firefox, or it may be something else... I'm not sure, but if you think there is a bug on the Firefox side related to that, please file a new one for it.

Comment 15

[Anton]

I will wait for an official release of FF and if Logitech fails, I will report as a bug

I don't think there is any point in reporting a bug in a beta

Comment 16

[Jean-Yves Avenard [:jya]]

(In reply to Anton from comment #15)
> I don't think there is any point in reporting a bug in a beta

quite the contrary, it allows time to ensure it's not broken in the next official release !

Comment 17

[Anton]

I have created a new bug

Bug 1194132

Comment 18

[Jean-Yves Avenard [:jya]]

in the mean time, you can remux your file not to use MP4 empty edit list (ISO/IEC 14496-12:2012 8.6.6.1)

I found that LibAV/FFmpeg always add those when remuxing from one container (typically mpeg-ts) to mp4 ; time offsets aren't properly supported on many devices (that includes android phones) ; there's often A/V sync issues with those.

my sony TV doesn't play those properly either.

Comment 19

[Anton]

thanks

I will wait for an official release that supports Logitech again and has the video delay fix such as FF41 already has

for now, back to 34.05 where everything works