Is there a way to ignore HTML5 video preload

[Demetrios Tsillas]

HTML5 video preloading is specified with the preload hint which, if respected by the browser, can cause the video to be buffered even if it is not played.

Is there a way to control whether this hint is respected?

If not, where would I look in the code to find where this hint is processed?

thanks!!!
-Jim.

[Mounir Lamouri]

Hi Demetrios,

+medi...@chromium.org

I'm assuming you want to be able to ignore the preload as a user. This
is not an option we directly offer in Chrome as blocking preload would
only work for file playbacks, excluding MSE playbacks and it might be
unclear for users why preloading works on some websites and not others.

We have been instead trying to offer better default behaviours. As as
example, on mobile, when the user turns on Data Saver or while using a
cellular connection, preload will be blocked when Chrome is in control.
Also, in Chrome 64, we are launching a change to our preload policy and
only the metadata will be downloaded by default unless the website asks
otherwise.

Thanks,
-- Mounir

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[Demetrios Tsillas]

Thank you so much for the reply!

My question is from a developer standpoint. As a developer I am modifying the desktop version of chromium to be a better browser on data capped network (such as satellite or cellular) one of the modification I want to make is to disable video preloading as much as possible, even at the expense of some user experience. Improving the default behavior is good but even better would be to provide an advanced user setting, at least for the class of users I am developing for.

If you can help me implement such a setting, it would be a big help. I have some experience in the chromium code base so I just need a starting point on where the preload hint handling is done.

thanks!!!
-Jim.

[Mounir Lamouri]

Hi Demetrios,

Sorry for the confusion :)

As a developer working on Chromium, you can call
`SetForcePreloadNoneForMediaElements()` on WebSettings [1]. This will
fully block preload. This is currently used in Chromium to block preload
on JB devices [2], you can use this as an example to use the WebSettings
API.

[1]
https://cs.chromium.org/chromium/src/third_party/WebKit/public/web/WebSettings.h?rcl=3d1e7a12b7be5570883f9b92871d9facd4c8138d&l=193
[2]
https://cs.chromium.org/chromium/src/content/renderer/render_view_impl.cc?rcl=3d1e7a12b7be5570883f9b92871d9facd4c8138d&l=962

Hope this helps,
-- Mounir

On Mon, 20 Nov 2017, at 13:45, Demetrios Tsillas wrote:
> Thank you so much for the reply!
>
> My question is from a developer standpoint. As a developer I am modifying
> the desktop version of chromium to be a better browser on data capped
> network (such as satellite or cellular) one of the modification I want to
> make is to disable video preloading as much as possible, even at the
> expense of some user experience. Improving the default behavior is good
> but
> even better would be to provide an advanced user setting, at least for
> the
> class of users I am developing for.
>
> If you can help me implement such a setting, it would be a big help. I
> have
> some experience in the chromium code base so I just need a starting point
> on where the preload hint handling is done.
>
> thanks!!!
> -Jim.
>
> On Monday, November 20, 2017 at 6:26:47 AM UTC-5, Mounir Lamouri wrote:
> >
> > Hi Demetrios,
> >

> > +medi...@chromium.org <javascript:>

> >
> > I'm assuming you want to be able to ignore the preload as a user. This
> > is not an option we directly offer in Chrome as blocking preload would
> > only work for file playbacks, excluding MSE playbacks and it might be
> > unclear for users why preloading works on some websites and not others.
> >
> > We have been instead trying to offer better default behaviours. As as
> > example, on mobile, when the user turns on Data Saver or while using a
> > cellular connection, preload will be blocked when Chrome is in control.
> > Also, in Chrome 64, we are launching a change to our preload policy and
> > only the metadata will be downloaded by default unless the website asks
> > otherwise.
> >
> > Thanks,
> > -- Mounir
> >
> > On Sat, 18 Nov 2017, at 13:06, Demetrios Tsillas wrote:
> > > HTML5 video preloading is specified with the preload hint which, if
> > > respected by the browser, can cause the video to be buffered even if it
> > > is
> > > not played.
> > >
> > > Is there a way to control whether this hint is respected?
> > >
> > > If not, where would I look in the code to find where this hint is
> > > processed?
> > >
> > > thanks!!!
> > > -Jim.
> > >
> > >
> > >
> > > --
> > > --

> > > Chromium Developers mailing list: chromi...@chromium.org <javascript:>

> > > View archives, change email options, or unsubscribe:
> > > http://groups.google.com/a/chromium.org/group/chromium-dev
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> > Groups
> > > "Chromium-dev" group.
> > > To unsubscribe from this group and stop receiving emails from it, send
> > an

> > > email to chromium-dev...@chromium.org <javascript:>.

> > > To view this discussion on the web visit
> > >
> > https://groups.google.com/a/chromium.org/d/msgid/chromium-dev/e81fb093-45ad-42fd-9933-9df6de1bff2c%40chromium.org.
> >
> >
>
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