On Sun Jan 15, 2023 at 10:49 PM CET, Pablo Rodriguez via ntg-context wrote:
> Dear list,
>
> I’m planning to add an explanation about multimedia inclusion to the
> wiki, but first I wanted to discuss an issue I have found.
>
> I have the following sample (adapted from scrn-wid.mklx):
>
>   \setupinteraction[state=start]
>   \starttext
>   \null\page
>   \definerenderingwindow[myrenderingwindow]
>     [width=\textwidth, height=\textwidth,
>      %openpageaction=StartCurrentRendering,
>      %closepageaction=StopCurrentRendering,
>      openpageaction=StartRendering{\currentrendering},
>      closepageaction=StopRendering{\currentrendering},
>      framecolor=red]
>   \startTEXpage[offset=1em, pagestate=start]
>   \userendering[key-name][video/mp4][video.mp4]
>     [embed=yes,
>      auto,
>      ]
>   \placerenderingwindow[myrenderingwindow][key-name]
>   \stopTEXpage
>   \null\page
>   \stoptext
>
> \userendering[][][auto] would enable automatic play or stop when the
> page with the rendering is reached or left (respectively).
>
> I cannot get it working. Neither do work the commented lines in
> \definerenderingwindow.
>
> Inspecting the PDF code, the screen annotation only gets an additional
> actions dictionary
> (https://opensource.adobe.com/dc-acrobat-sdk-docs/standards/pdfstandards/pdf/PDF32000_2008.pdf#G11.2096829)
> with /PO and /PC entries, when open and close page actions are set to
> StartRendering{\currentrendering} and StopRendering{\currentrendering}.
>
> Just for reference, this is the screen annotation object with the
> additional actions dictionary:
>
>   13 0 obj
>   <<
>     /Type /Annot
>     /A <<
>       /AN 13 0 R
>       /OP 0
>       /R 12 0 R
>       /S /Rendition
>     >>
>     /AA <<
>       /PC <<
>         /AN 13 0 R
>         /OP 1
>         /R 12 0 R
>         /S /Rendition
>       >>
>       /PO <<
>         /AN 13 0 R
>         /OP 0
>         /R 12 0 R
>         /S /Rendition
>       >>
>     >>
>     /Border [ 0 0 0 ]
>     /P 14 0 R
>     /Subtype /Screen
>     /T <FEFF006B00650079002D006E0061006D0065>
>     /Rect [ 12.353668 12.353668 437.54664 437.54664 ]
>   >>
>   endobj
>
> And this is what I get with \userendering[][][auto]:
>
>   13 0 obj
>   <<
>     /Type /Annot
>     /A <<
>       /AN 13 0 R
>       /OP 0
>       /R 12 0 R
>       /S /Rendition
>     >>
>     /Border [ 0 0 0 ]
>     /P 14 0 R
>     /Subtype /Screen
>     /T <FEFF006B00650079002D006E0061006D0065>
>     /Rect [ 12.353668 12.353668 437.54664 437.54664 ]
>   >>
>   endobj
>
> Could anyone be so kind to confirm the issue?

AFAICT I based the auto option on the "Start/StopCurrentRendering"
actions (2021-09-14) which we later agreed to remove (2021-09-17), so
there was a bug. Reasoning for removal of the "Current" variants at the
time:

On Tue Sep 14, 2021 at 9:37 PM CEST, Hans Hagen wrote:
> Because \currentrendering is local we could as well drop the Current 
> variants ... it's not like people will put hundreds of videos in a file 
> so enforcing the named one makes sense.

So Start/StopRendering{label} should be used instead (Hans already redid
most of the examples, you found the two places in scrn-wid.mklx where
there is an incosistency.

I would think that something like the attached could work. But in some
cases it fails on the TeX side with something I am not sure about. I
probably overlooked something. Anyways the idea is to just use the
Start/StopRendering actions with the correct label.

Michal