When rendering a clip that is longer than the batch duration, every frame rendered after the length of the batch duration is black.
If my render range is 50 and my batch duration is 25. Every frame rendered after the 25th will be black.
I recently had a disagreement with someone about whether this was the expected/desired behavior and I’m curious to know what other people think.
Nop, Black frames is not the expected behavior. I’ve just check it out just in case. Maybe you have some mux node, or source clips properties set as “Use black” in Head/Gap/Tail media properties.
I frequently make renders longer than the batch duration. I’ve never had them render black. I believe there may be some preferences that relate to what @kily mentioned.
Thank you both, @kily and @ytf for the replies. You are indeed correct that this is not the default behavior. I probably should have investigated a little bit more before posting.
I was able to track the issue down to OFX. It appears that by default OFX plugins will take the batch duration instead of the source duration. I would prefer it didn’t, but it likely seems unavoidable since it opens up the risk of feeding in a source of infinite duration.
Thanks for finding this… I’ve had a similar issue and didn’t bother tracking it down.
I have sapphire OFX and I’m not seeing this behaviour. 2026.1 on linux
That makes sense. I rarely use sapphires so I didn’t bother testing there, but the behavior is present in the Mocha and Neat OFX plugins.
I think the distinction is probably, does the OFX take you out of Flame to a secondary UI or not. It would stand to reason that since sapphires(for the most part?) can be used within Flame that they don’t have this issue.
My uninformed idiot artist-level intuition is that the OFX with external interfaces need to be fed a frame range when you start them up and for a variety of reasons it may not be possible to pass the source frame range and thus the batch duration is being used instead.
The risk is probably that you give a clip of infinite duration(procedural texture, color source, etc) to one of these plugins and it doesn’t know how to determine the frame range on its own so it needs some kind of limiting factor(batch duration).
You can manually set the FX Range in the OFX plugin tab to pass a different duration to the node.
We use an autopopulated default batch template for all of our shots and I’m considering whether it would be prudent to use an Active FX Range for our Neat nodes, set to something like 1000, in order to bypass this situation. Might solve one edge case while creating another though. Still need to ruminate and test a bit more.
I would love it if this could be solved a different way though. Setting a random long default Active FX Range as a solution is triggering to my neuroses.
Oooohhh…this totally explains an issue I was running into this week w/ Neat and pre-rendering an element that was longer than the batch duration. 2025 btw.
Did you open a support case?
I use neat denoise ofently, and I never seen that. I’ve just check it out, rendering 100 frames extra to bach duration and it renders normally. Flame 2026.1 linux, and I would say that in previous versions either, because this is a scenario that happens to me frequently and I never get black frames.
I’m working towards getting my company to submit a ticket for this issue. This thread has been helpful in making the case that this problem may require further study. Thank you everyone!
Yeah I always have this problem with Neat. V annoying
IIR, this happens with most plugins if the duration is different to the batch duration