- From: Mark Watson <watsonm@netflix.com>
- Date: Tue, 18 Nov 2014 12:54:46 -0800
- To: "Tab Atkins Jr." <jackalmage@gmail.com>
- Cc: "L. David Baron" <dbaron@dbaron.org>, Florian Rivoal <florian@rivoal.net>, "www-style@w3.org" <www-style@w3.org>
- Message-ID: <CAEnTvdAbisDxcCFn5YY9zCzSus7NoirDYb1CHgKWoJ9rSs_-4g@mail.gmail.com>
On Tue, Nov 18, 2014 at 12:43 PM, Tab Atkins Jr. <jackalmage@gmail.com> wrote: > On Tue, Nov 18, 2014 at 12:20 PM, Mark Watson <watsonm@netflix.com> wrote: > > On Tue, Nov 18, 2014 at 9:45 AM, Tab Atkins Jr. <jackalmage@gmail.com> > > wrote: > >> This might be something we need to solve in HTML, by adopting > >> something analogous to srcset. Or, if we're okay with letting CSS > >> override <video> source selection, we can solve it with something > >> parallel to image-set(), specialized for videos. > > > > I think it's clear that for the <source> / @srcset case, then giving the > UA > > the information is needs to make the choice is the right solution. > > > > For our use-case, though, we are using the Media Source Extension so it > is > > fundamentally the script that decides which stream is downloaded. So the > > script needs the same information the UA would use in a declarative > setting. > > Ah, if scripting is involved, this is easier. window.devicePixelRatio > gives you the screen density on all webkit/blink/ff browsers (dunno > about IE). You can then just measure the element normally using > existing JS APIs, and use those two pieces of information to figure > out what source to load. > There are two issues with that approach: (1) I'm buffering ahead of time, so really I am interested in what the situation would be if the video went fullscreen (2) There are scenarios where video gets downscaled, most notably when output over HDMI (due to HDCP, yes, I know), and in these scenarios I am interested in the actual output resolution (after downscaling) ...Mark > > Discounting any connection speed-based decision-making browsers might > do, this is the same information that the browser uses to decide > srcset stuff. > > ~TJ >
Received on Tuesday, 18 November 2014 20:55:14 UTC