1322283 - Some mp4 videos will not play at all or only for a second or so; abnormally high cpu usage

Status: RESOLVED WORKSFORME

(Core :: Audio/Video: Playback, defect, P3)

Description

[Dave]

User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:50.0) Gecko/20100101 Firefox/50.0
Build ID: 20161129173726

Steps to reproduce:

Go to http://i.imgur.com/hMda9Is.gifv, or http://i.imgur.com/hMda9Is.mp4, or download the mp4 in question and play it locally. This affects only a tiny amount of videos, most videos play normally.




Actual results:

Results vary according to Firefox version.

On a clean 50.0.2 profile, and also on 49:

* when navigating to .mp4 directly:
  * preview image is shown before i press the play button
  * when i press the play button, there's about 0.5 second pause first
  * then the image dims and loading animation appears
  * the the image stays still for a second,
  * then there's about 0.5s of actual animation that doesn't start at the beginning of the video
  * then, after ~2 seconds, the slider hits 0:08s mark (end), the video un-dims, and everything stops
  * during these ~2 seconds, cpu usage is about 100% on all cores
* when going to .gifv:
  * it's the same, but looping; cpu drops slightly when it “rewinds”, so cpu usage graph looks like /\/\/\/\/\

To make it clear, the whole “playback” takes about 2s while the video is 8s long, and i see about 0.5s of actual animation.

On a clean 52.0a2 profile (firefox developer):

* when navigating to .gifv url:
  * preview image doesn't show, i see a black rectangle of appropriate size instead, and it stays like that
  * show controls doesn't show anything
  * cpu usage is constant, around 35%, drops to 0 when i pause the non-existent video by right clicking -> pause, rises back when i resume it
* when navigating to .mp4 directly:
  * no preview image, the “video” is transparent, that is the same as the background
  * when i press play (there are controls), it instantly jumps to 0:08s (end) and that's it

Windows 10 pro on x220 with i5-2520m and 4gb of ram


Expected results:

I expected this video to play like other videos

Comment 1

[Loic]

This MP4 video has a long history of broken playback!

The video worked fine in FF44, then broke in FF45: only the 1st sec plays then the playback stops and the seekbar goes to the end. It's due to Bug 1217185:
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=d51826
1eb3b17f3e6b11fdb6d55ec1b7d4b11901&tochange=f24cb2c2ddf0c91eafe64ee868f78b40d9c6
901f

In FF50, it has been worse with a loading animation when starting playback after bug 1272267:
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=28176df6d571538bc28ec2ed88177ccd5da707ab&tochange=fb8ee867138d4b92ddd3efbf39a755b0fe7eb272

Good news! The playback has been fixed in some FF52 nightlies in mid-October.
You can test with http://ftp.mozilla.org/pub/firefox/nightly/2016/10/2016-10-25-03-02-05-mozilla-central/firefox-52.0a1.en-US.win32.zip it works fine.

But it broke again after Bug 1311594:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=9fb2ac0875ec35268701dd3826b017a301cc7400&tochange=2be061c5d070c962862c62bed8171b5d41654533

Now, in FF52/53, there is no more playback, it jumps directly to the end and FF displays a black screen.
I request tracking flags for 52/53 because the playback is completely broken.

Comment 2

[Dave]

Can confirm 52.0a1 from your link appears to be working fine

Comment 3

[JW Wang [:jwwang] [:jw_wang]]

(In reply to Loic from comment #1)
> But it broke again after Bug 1311594:
> https://hg.mozilla.org/integration/autoland/
> pushloghtml?fromchange=9fb2ac0875ec35268701dd3826b017a301cc7400&tochange=2be0
> 61c5d070c962862c62bed8171b5d41654533

I don't think bug 1311594 is a regression which changes the behavior only when playback reaches the end. Since this bug is about the beginning of playback, it should be innocent.

Btw, I can't repro this bug on OSX nightly.

Comment 4

[Milan Sreckovic [:milan] (needinfo for best results)]

Dave, can you attach the graphics section of about:support?

Comment 5

[Liz Henry (:lizzard) (relman/hg->git project)]

Andrei, can  your team try to reproduce the issue and attach the graphics section of about:support if you're able to?  
This problem doesn't appear to be widespread, and we're close to the end of the 51 beta cycle, so I think it's reasonable to aim to fix this in 53.

Comment 6

[Anthony Jones (:ajones, :kentuckyfriedtakahe, :k17e)]

Playing http://i.imgur.com/hMda9Is.mp4 plays for me in nightly on Windows 10.

Comment 7

[Loic]

Still broken for me.

Comment 8

[Anthony Jones (:ajones, :kentuckyfriedtakahe, :k17e)]

(In reply to Loic from comment #7)
> Still broken for me.

Can you provide the graphics section of about:support please?

Comment 9

[Loic]

Attachment: about-support.txt

(In reply to Anthony Jones (:kentuckyfriedtakahe, :k17e) from comment #8)
> (In reply to Loic from comment #7)
> > Still broken for me.
> 
> Can you provide the graphics section of about:support please?

Done.

Comment 10

[Liz Henry (:lizzard) (relman/hg->git project)]

Wontfix for 53 as no one is actively investigating. 
Anthony, do you want to find someone to take on this issue? I don't know if 54 or 55 are affected. We could ask QE to try to replicate it if you like.

Comment 11

[Blake Wu [:bwu][:blakewu]]

Ni myself to see if I can find someone to help on this bug.

Comment 12

[Blake Wu [:bwu][:blakewu]]

I cannot repro this problem on Firefox 52, 53, and the latest nightly on my windows 10 laptop.

Comment 13

[Alex Chronopoulos [:achronop]]

I am closing it because it is inactive for 2 years, feel free to reopen.

Comment 14

[Dave]

works fine now