Video output VERY slow when rendering/animating mulitple scenes (movie only, no 3d)

Hi,

I’m new to basicly all of this, so I’m not sure I’m even in the right forum. If not, please move the post or point me to a better place for this problem. I am also unsure about the right terminology because its also a 3d-program and there are surely differences between “rendering” and “animating” but I don’t know what they are when it comes to movies.

I am cutting a short movie. 3 minutes (9000 frames). I have created several scenes. One for each scene of the movie. A scene looks like this, when I’m done with it. (please see picture 1)
If I hit the animation-button it renders it out the way i want at a reasonable speed (10 frames per second - give or take).

I than created another scene in which I imported all the others via “add->scene” so I can move them around, put them in the right order, watch the movie a a whole an so on. (please see picture 2)

BUT when I hit the animation-button know it crawls like hell. 1 frame per second or WORSE. I don’t understand why.

Am I doing something wrong? Isn’t this how movies are made (serious question)?

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I’m going to make the assumption that your working from a single blend file, Its a little hard to tell from your description. As a best practice Its always good to render out each individual scene first, ideally as an image sequences such as png or something similar; after that open up a completely separate blender file and use the sequence editor to bring in your image sequnces or videos (add -> image strip and hitting ctrl A will bring in the whole strip ) and cut it together then, this avoids the crazy render slow downs your experiencing.

what I’m assuming is happening in your sequence editor is that your telling blender to take your scene, render it out, which takes a little while depending on the complexity, if you have any compositing going on blender that’ll slow down the rendering process further and by using the sequence editor to do that to multiple scenes = a really long time waiting.

hope this helps
best jelly

I have come to the conclusion, that it is some kind of bug.

I also encountered another Problem. It seems to be a bug to and been known for quite some time.
The imported scenes had messed up keyframes. The keyframes were not in the right place. Say in scene “A” I had a fade at 01:00. If you import the scene the way I described into “final” scene “A” might be half way into the movie. The keyframes however were still at 01:00. If you moved “A” to the very begining of the movie you could see it taking effect. BUT the keyframes for sound was uneffected.

So: I rendered out each scene on its own. But when I stichted them together with ffmpeg, I had A/V-synchronization issues half way into the film. I don’t know why. So I let blender give out a soundstrip for the entire movie. Thank god, the keyframes for sound worked in “final”. Then I stichted together the pieces underlying it with the soundstrip of “final”. That worked.

But next time I will use just one blener-scene and manage the scenes of the movie with metastrips. Seems saver.