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Re: What does a track contain?

From: Peter Thatcher <pthatcher@google.com>
Date: Wed, 24 Feb 2016 08:28:11 -0800
Message-ID: <CAJrXDUGxGaboKPTN4i4PZdOOWx40sRoArsRvP4iracNViAcAkw@mail.gmail.com>
To: Martin Thomson <martin.thomson@gmail.com>
Cc: "public-media-capture@w3.org" <public-media-capture@w3.org>
I don't know enough about <video> to know the answer to this:  if it has an
alpha channel in it, and it's rendered on top of other web elements, is it
supposed to render such that you potentially see through the video to the
other web elements below?  In other words, could I use a <video> to make a
video of a translucent ghost fly around a web page?  Is that the kind of
thing we're going for here?   canvas -> track -> <video> -> ghost?

On Wed, Feb 24, 2016 at 8:20 AM, Martin Thomson <martin.thomson@gmail.com>
wrote:

> On 24 February 2016 at 08:13, Peter Thatcher <pthatcher@google.com> wrote:
> > What do you mean "throughout the media pipeline"?  Do you expect a track
> > sent through a PeerConnection to have the alpha channel intact when it
> comes
> > out the remote side?
>
> Well, we know that RTP video is generally incapable of handling alpha
> channels, so no.  Unless and until we find a codec that supports an
> alpha channel (APNG perhaps).
>
> But the simple example of <canvas> piped to <video> presents something
> of a challenge.
>
Received on Wednesday, 24 February 2016 16:29:19 UTC

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