[M4IF Technotes] MediaControl node problem

[Jean-Claude Dufourd]

Christian Weigel wrote:
>The strange thing is, that there are scenes where exactly the same works
>perfectly (ENST conformance Bitstreams:
>Advanced2D_Level1\Envivio\mediacontrol)
>
Precision: the files are *downloadable* from ENST web site, but this 
file comes, as the directory name says, from Envivio, the creator of 
EnvivioTV.
>If I deactivate the mediaStream by setting the stopTime field of the
>MovieTexture to NOW it stops. But if I reactivate it (by setting the
>startTime field to NOW) it plays not from the time it was stopped (like
>it is said in the standard when the MediaControlNode.startMediaTime is
>-1) but so as if it has never been stopped (it jumps forward)
>
This is as it should be. The standard says exactly this. When a 
MediaControl is present and active, then the MovieTexture fields are 
just doing mute and demute.
I have had problems with the EnvivioTV MediaControl implementation, but 
it comes from their interpretation of the spec, that you need to mute 
the video for a change in MediaControl fields to have an effect.
>I found out, that after extraction and
>remuxing of the stream its properties differ a little,e.g. mp4info says
>with the original stream:
>
mp4tool had bugs: rounding of the duration, losing the width and height 
BUT it computes the bitrate exactly!
If the video plays without MediaControl, then there is no consequence.
Best regards
JC