YouTube videos stuttering and not playing back smoothly

[Bill Filler]

rtm build 224 on krillin
on fast wifi connection

- Go to videos scope
- Choose the first YouTube video
- Play it in YouTube and maximize the screen

Expected results:
- The video should play back smoothly

Actual results:
- The video pauses frequently and stutters
- The progress bar shows it's not a buffering issue as most of the video has been downloaded already

This is new. Wondering if it could be related to the YouTube user-agent string

Note: oxide-renderer process is using 180% CPU according to top when the video is being played back

[Bill Filler (bfiller)]

Might not be specific to YouTube, seeing it on cnn.com as well trying to play this video:
http://www.cnn.com/2015/02/02/us/super-bowl-5-things/index.html

[Olivier Tilloy (osomon)]

I can easily reproduce the issue.
Some observations:

 - the issue affects krillin, both the latest rtm-proposed and vivid-proposed
 - on krillin, I’m seeing the 180% CPU usage by oxide-renderer (both rtm and vivid)
 - the issue doesn’t affect my nexus 7 on the latest vivid-proposed
 - on nexus 7, the CPU usage of oxide-renderer is capped at 99%

[Olivier Tilloy (osomon)]

On krillin, if I cap the CPU usage of oxide-renderer at e.g. 80% (using cpulimit), the stuttering goes away, but the resolution of the video is visibly degraded. It seems youtube uses adaptive bitrate streaming.

[David Barth (dbarth)]

This is similar and linked to https://bugs.launchpad.net/oxide/+bug/1414743

[David Barth (dbarth)]

Justin recently investigated the ebay ad problem and we have a few theories here:

1. The high cpu usage is due to a highdef video format that is pushing the limits of what our HW can support. However, trying various user-agent strings for higher-end or lower-end devices did not change the type of video that was sent. So we can infer that the video we are sent is the one meant for our class of devices.

2. The high cpu usage is due to a switch of Youtube to using by default a new MediaSource construct. In particular, this involves demuxing the stream in the webview, in javascript. That may explain the higher cpu usage, causing the dropped frames. However, since that does not happen on Android, it would highlight a performance problem in our port the chrome engine. If the difference is mostly the js demuxing, that would indicate a v8 engine performance problem. Or maybe the fact that once processed the stream is sent via JS to a construct (the video frame) with a higher penalty than on other platforms.

3. This behavior is limited to Youtbe, and other video sites like Vimeo or Dailymotion seem to work fine for all of the popular video we have tested.

[Ricardo Salveti (rsalveti)]

Remember that android doesn't do software decoding, so while it might consume more CPU, it might still be fine for Android. In our case we're adding that on top of a heavily software decoding process.

[Olivier Tilloy (osomon)]

Ricardo, is there a way to enforce CPU usage limitations on a given process in Ubuntu Touch?
I’m thinking that if we were able to somehow declare that oxide-renderer is not allowed to use more than 80% CPU, then this would fix the issue (by ensuring the youtube serves a lower-resolution video).

[David Barth (dbarth)]

I investigated further, and reverted my krillin to image #9, and then upgrade to the current #16 image.
With the older #9 image, the CPU usage is about 50% for the oxide renderer process. If switching to #16, the CPU usage goes through the roof at 150+% (120% on average).

[David Barth (dbarth)]

Upgrading the #9 RTM image to use the newest oxide, ie from 1.3.4 to 1.3.5, I observe that the cpu usage is still contained, ie around 50% for the main renderer process. The browser process consumes about 40% which is on par with what I was observing with 1.3.4.

So overall, it doesn't seem to be an oxide regression.

[David Barth (dbarth)]

Upgrading to the newest webbrowser-app triggers the frame skipping again.

ie: it works fine with: 0.23+15.04.20141118~rtm-0ubuntu1
but burns a lot of cpu with: 0.23+15.04.20150127~rtm-0ubuntu1

Not sure if this is webbrowser-app, or another interaction it has with oxide or mir though, or the newer UA string.

[Bill Filler (bfiller)]

confirming that reverting the UA string to old version fixes the stuttering when using youtube webapp or visiting youtube in browser.

But it doesn't fix problem where pages have embedded youtube videos, like this:
http://m.bleacherreport.com/articles/2352016-papa-johns-airs-wrong-commercial-congratulates-seahawks-after-super-bowl

These still exhibit the problem even with the youtube specific UA string

[Launchpad Janitor (janitor)]

This bug was fixed in the package webbrowser-app - 0.23+15.04.20150203.1-0ubuntu1

---------------
webbrowser-app (0.23+15.04.20150203.1-0ubuntu1) vivid; urgency=medium

  [ Olivier Tilloy ]
  * Update translation template.
  * Revert the UA override for m.youtube.com as it was causing a lot of
    stuttering (due to very high CPU usage) on krillin. In the meantime,
    the issue with videos not playing that this update was meant to
    address (bug #1415107) was resolved on youtube’s side. (LP:
    #1417258, #1415107)
 -- Ubuntu daily release <email address hidden> Tue, 03 Feb 2015 17:35:27 +0000

[David Barth (dbarth)]

I confirm the change also fixes the problem on rtm (silo 8)

On Wed, Feb 4, 2015 at 7:16 AM, Olivier Tilloy <<email address hidden>
> wrote:

> ** Changed in: webbrowser-app
> Status: In Progress => Fix Released
>
> ** Changed in: canonical-devices-system-image
> Assignee: (unassigned) => Olivier Tilloy (osomon)
>
> ** Changed in: webbrowser-app (Ubuntu RTM)
> Status: Confirmed => In Progress
>
> ** Changed in: webbrowser-app (Ubuntu RTM)
> Assignee: (unassigned) => Olivier Tilloy (osomon)
>
> --
> You received this bug notification because you are a member of Ubuntu
> WebApps bug tracking, which is subscribed to Oxide.
> https://bugs.launchpad.net/bugs/1417258
>
> Title:
> YouTube videos stuttering and not playing back smoothly
>
> Status in the base for Ubuntu mobile products:
> In Progress
> Status in Oxide Webview:
> Invalid
> Status in Web Browser App:
> Fix Released
> Status in webbrowser-app package in Ubuntu:
> Fix Released
> Status in webbrowser-app package in Ubuntu RTM:
> In Progress
>
> Bug description:
> rtm build 224 on krillin
> on fast wifi connection
>
> - Go to videos scope
> - Choose the first YouTube video
> - Play it in YouTube and maximize the screen
>
> Expected results:
> - The video should play back smoothly
>
> Actual results:
> - The video pauses frequently and stutters
> - The progress bar shows it's not a buffering issue as most of the video
> has been downloaded already
>
> This is new. Wondering if it could be related to the YouTube user-
> agent string
>
> Note: oxide-renderer process is using 180% CPU according to top when
> the video is being played back
>
> To manage notifications about this bug go to:
>
> https://bugs.launchpad.net/canonical-devices-system-image/+bug/1417258/+subscriptions
>
> --
> Mailing list: https://launchpad.net/~ubuntu-webapps-bugs
> Post to : <email address hidden>
> Unsubscribe : https://launchpad.net/~ubuntu-webapps-bugs
> More help : https://help.launchpad.net/ListHelp
>

[Víctor R. Ruiz (vrruiz)]

With silo 8 packages (see below), I still cannot reproduce this video smoothly, gets over 150% CPU usage: http://pages.ebay.com/shoptheworld/

current build number: 226
device name: krillin
channel: ubuntu-touch/ubuntu-rtm/14.09-proposed

Upgrade: qtdeclarative5-ubuntu-web-plugin:armhf (0.23+15.04.20150127~rtm-0ubuntu1, 0.23+15.04.20150203~rtm-0ubuntu1), qtdeclarative5-ubuntu-ui-extras-browser-plugin:armhf (0.23+15.04.20150127~rtm-0ubuntu1, 0.23+15.04.20150203~rtm-0ubuntu1), webbrowser-app:armhf (0.23+15.04.20150127~rtm-0ubuntu1, 0.23+15.04.20150203~rtm-0ubuntu1), qtdeclarative5-ubuntu-web-plugin-assets:armhf (0.23+15.04.20150127~rtm-0ubuntu1, 0.23+15.04.20150203~rtm-0ubuntu1), webapp-container:armhf (0.23+15.04.20150127~rtm-0ubuntu1, 0.23+15.04.20150203~rtm-0ubuntu1)

[Olivier Tilloy (osomon)]

Victor, silo 8 only fixes videos on youtube.com. It won’t address playback issues on other websites. That’s because it’s a UA string override for m.youtube.com.
Let’s track similar issues for other websites in different bugs, please.

[Launchpad Janitor (janitor)]

This bug was fixed in the package webbrowser-app - 0.23+15.04.20150203~rtm-0ubuntu1

---------------
webbrowser-app (0.23+15.04.20150203~rtm-0ubuntu1) 14.09; urgency=medium

  [ Olivier Tilloy ]
  * Revert the UA override for m.youtube.com as it was causing a lot of
    stuttering (due to very high CPU usage) on krillin. In the meantime,
    the issue with videos not playing that this update was meant to
    address (bug #1415107) was resolved on youtube’s side. (LP:
    #1417258, #1415107)
 -- Ubuntu daily release <email address hidden> Tue, 03 Feb 2015 17:35:26 +0000

[Bill Filler (bfiller)]

filed this bug to track problems with embeded YouTube videos that are not addressed by this fix:
https://bugs.launchpad.net/ubuntu/+source/webbrowser-app/+bug/1418626