[Bf-funboard] VSE to compositor to VSE pipeline

David McSween 3pointedit at gmail.com
Wed Aug 26 14:30:54 CEST 2015


Hi Olivier,

The approach that you describe is currently opposite to the workflow
engendered in Blender. That is all production typically flows down the pipe
ending at the VSE.

Perhaps you are asking for something other than VSE>Compositor? For
example, Compositing nodes in the VSE. But this is challenging to implement
in a timeline (top down or vertically stacked media) system. How would
media in a timeline function when a node is swapped?

To access the compositor's effects you must "reconstruct" your VSE edit
decisions, that is timing media relative to each other and the scene master
time. Then feed the result back to the VSE as a "scene strip".

Why would we want to use the VSE instead of the compositor to build effects?
I imagine that it is because of the more interactive nature of timeline
editing. Being able to play back elements and judge timing and duration of
performance. This is impossible in the compositor, but many performance
based changes need to be made in the compositor requiring access to
realtime playback.

Did you know that something like this already exists in Blender's workflow?
If you create a 3D scene with multiple cameras you can actually switch the
output of the "Scene Render Layer Input node" by switching a scene strip in
the VSE.

So you can affect an input node directly from the VSE.

I might suggest a new class of strip. One that can access Texture
Datablocks. The VSE strip would drive the scene relative offset (starting
time) and the media's start frame offset and of course its duration. Then
it would function just like a scene strip with camera switching in the
compositor/VSE. Directing the input of a (new) "Texture Input Node" in the
compositor.


OR

We could create a XML (database) export/import to handle editing decisions
between the VSE and the compositor. This would recreate the VSE strips
timing as input nodes in an alternate scene. But no interaction would be
allowed, you would need a vision locked VSE timeline before exporting.

I hope this discussion has been of help

P.S. Sorry Troy ;-)

On Tue, Aug 25, 2015 at 12:24 AM, Olivier Haveloch <olivierphoto03 at gmail.com
> wrote:

> Hi everybody,
>
> Blender's ability to go from the VSE to the compositor and back to the
> VSE is great. There is an addon that makes the process a bit more user
> friendly (link bellow). Yet, when doing a VSE to comp to VSE, playback
> of the added strip in the VSE is very slow and rendering time of these
> strips edited with the compositor is really really long.
>
> I've exchange on this with Julian Eisel who said the following:
> "I think the slow playback speed is mostly due to the Add-on that
> manages the data flow (python is much slower than C) but I'd guess
> that the compositor also needs to re-composit for every frame? Not
> sure about that though... However, there is an issue with
> VSE<->Compositor communication, that many people overlook: While being
> able to input data from the
> Compositor to the VSE is fine, it can't work the other way around in
> parallel, since this would create a circular data flow. From a
> pipeline perspective, VSE and Compositor are to different editing
> stages. Compositor is basically for combining/compositing elements,
> VSE is for video editing and final touches. The work in the Compositor
> should always be done before the VSE is touched. That said, it's also
> fine to have some Add-ons providing limited support for
> VSE->Compositor workflow, but doing this in the C backend would be
> highly dangerous. The VSE definitely needs a rewrite."
>
> Edit script with compositor addon:
>
> http://blenderartists.org/forum/showthread.php?221567-Edit-strip-with-compositor&p=2236974&viewfull=1#post2236974
>
> Cheers,
>
> Olivier
> _______________________________________________
> Bf-funboard mailing list
> Bf-funboard at blender.org
> http://lists.blender.org/mailman/listinfo/bf-funboard
>


More information about the Bf-funboard mailing list