[Bf-funboard] VSE to compositor to VSE pipeline

[Olivier Haveloch]

Hi David,

I agree that many use the VSE only to edit 3D renders down the pipe.
Yet the VSE is a very decent editing software as you know and if it
had a few extra features it could definitely become a professional
video editing software and it would be used a lot more than it is by
independent filmmakers. Going from an editing software to a
compositing software and back to the editing software is a very common
workflow when editing video, hence my suggestion to improve the VSE to
comp to VSE pipeline. Alternatively adding more features to the VSE
(as effect strips and/or adjustment layers) may be easier to
implement?
I will look into what you've suggested (Scene Render Layer Input
node/switching a scene strip in the VSE), have you done by any chance
a video tutorial on this? Your tutorials by the way are great!

Best,

Olivier




On Wed, Aug 26, 2015 at 2:30 PM, David McSween <3pointedit at gmail.com> wrote:
> 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
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