[M4IF Technotes] MediaControl node problem

[Jean-Claude Dufourd]

Christian Weigel wrote:
>I assume that mute and demute is the same as deactivation and activation
>of the MovieTexture.
>
Yes
> If so I am a little confused because in the
>standard in section 9.4.2.75.2 is written: 
>
>"When the controlled stream becomes inactive and then active again, then
>if mediaStartTime is -1 the stream starts playing from the point where
>it was last stopped. Otherwise the first controlled stream object in the
>url field restarts playing from mediaStartTime."
>
What I remember from the discussions around MediaControl is, when 
MediaControl is present, the MovieTexture field manipulation has NO 
consequence on the stream at all. This means the formulation above is 
unfortunate. I would welcome confirmation of  my statement by people 
more knowledgeable about MediaControl (Zvi, Yuval, Carsten, Jean, Cyril...)
>So if the MediaControl's is mediaStartTime field is set to -1 (which it
>is by default) it should be possible to PAUSE the video by muting
>(deactivate) it and to CONTINUE it at the point in media Time where it
>was paused by demuting it. Or do I unterstand something the wrong way.
>
>I looked in the envivio sample how they have done it and they did it
>exactly like this and it works.
>
No, they did not do it exactly like that. Here is the relevant script 
node from this file (which I know almost by heart now from trying to 
understand the way Envivio implemented MediaControl):
DEF N40 Script {
    url "javascript:function setTime(value, timestamp) {
        if (value) {
          video1.stopTime = timestamp;
          control.mediaStartTime =  ( what.translation.x + 40 )  / 8.8;
        } else
          video1.startTime = timestamp;
    }
[snip] "
      eventIn SFVec2f setVolume
      eventIn SFBool setTime
      eventOut SFFloat transpar1
      field SFNode video1 USE N29
      field SFNode what USE N17
      field SFNode control USE N33
    }
N29 is the MovieTexture
N33 is the MediaControl
They are doing:
- on isActive=true (mouse button down), N29.stopTime=now and 
N33.mediaStartTime=something
- on isActive=false (mouse button up), N29.startTime=now (which is 
necessarily another "now" than above)
If you do not do it this way, the MediaControl ignores your changes, 
which is wrong in my interpretation of the standard, but this is moot.
I could not make my scenes work, so I'll stop here. I cannot make 
constructive suggestions. I tried emulating the above with Conditionals, 
to no avail.
We are working on implementing MediaControl in Osmose: it is supposed to 
work as of last Thrusday. I have yet to test it.
Best regards
JC