Timeline scaling problem getting just ridiculous

I've put up with all those weird little things connected with scaling timelines when including them in another timelines. And there's been a lot of topics about this, like theese, just for example:

viewtopic.php?f=21&t=101842
viewtopic.php?f=21&t=93010
viewtopic.php?f=21&t=100246
viewtopic.php?f=21&t=106408
viewtopic.php?f=32&t=95076

... all of them with no decent or definitive answer, prefferably from the staff... So I just went along with it. But today, a whole year later after I came accross my first issues of this kind, I believe I found a case, which is just ridiculous and it drives me absolutely mad. I made a little video of it:

(apparently I'm not allowed to post links directly, so please just copy to your browser, sorry for the inconvenience)

youtube.com/watch?v=QnX4MF2VI9o

I have two timelines, both THE VERY SAME RESOLUTION, with all the scaling taken care of in the first one, but still, when the first one is included into the other, it does not work as it absolutely should.

I dare anyone to tell me this behavior is expected and correct. Nonsense! Yeah the original footage clips are higher resolution, but that's exactly why I have the extra timeline there! To resize them! Don't even try to tell me I should resize the originals! What if I want to use the same footage more than once, each time with different "zoom" or position!? Ha! That's where your "you should resize the originals" stops being such I useful advice...

Oh and if I see the "you know, timeline is like a picture frame..." thing here... No it's not! It's a timeline, not a picture frame

Yeah it could be a multicam issue. And if it is, it's still the same absurdity, so it doesn't change anything.

Yeah, there's a workaround in having the first timeline the same resulution as the original footage, than scaling the footage inside the timeline to 2560x1440, leaving a huge black border around it, and THAN it fits nicely into the second timeline. But if this is not absolutely absurd, then I don't know what is...

I know Resolve is free or very cheap in pro version, compared to the other (subscription based) software out there. And I know it has absolutely the best capabilities of color grading in the world right now... But this is SUCH A BASIC piece of functionality, the other software does absolutely seemlesly in a logical ways... That's the reason it frustrates me so much... It's absolutely ruining the experience...

Pleeeeeaase someone tell me this is getting fixed soon, and that it is a priority. I would so love to hear it...

Love the software otherwise...

Upon further investigation, I now know, it's not a multicam issue. It happens with the simplest timelines imaginable containing a single clip of original footage as well. There is a difference though:

The seemingly stupid workaround I proposed in my original post will not work for timelines containing multicam. In fact, it makes thinks even worse for those. It does work for non-multicam timelines though. I made another video demonstrating the behavior:

youtube.com/watch?v=kTqEy48ms4g

My version is 16.2.4.016 and after manualy checking, it seems there is 16.2.5 out, so I'm going to check it out.

Edit: Nope, everything exactly the same in 15.2.5.015.

I dare anyone to tell me this behavior is expected and correct. Don't even try to tell me I should resize the originals! What if I want to use the same footage more than once, each time with different "zoom" or position!?

That is the expected and correct behavior. You should resize the originals. If you want to apply different effects on different parts of the clip, don't nest.

I dare anyone to tell me this behavior is expected and correct. Don't even try to tell me I should resize the originals! What if I want to use the same footage more than once, each time with different "zoom" or position!?

That is the expected and correct behavior. You should resize the originals. If you want to apply different effects on different parts of the clip, don't nest.

I simply refuse to believe it's the correct behavior I'm so sorry, but I just do

The simplest way I can put my thoughts in text: Is it really correct behavior, when the timeline has different output when viewed separately from inserted when into another timeline? Because that's what's happening here.

Is there anything which prevents you from decomposing compound clips and nested timelines, to have available the original resolution?

Is there anything which prevents you from decomposing compound clips and nested timelines, to have available the original resolution?

Yeah I just came accross that, it works MUCH better and solves most of my problems! Except...

... It does not work as a solution for multicam I'm trying to find some workaround for that as well, but no luck yet...

Thanks for the answer though, glad to know I might be heading the right direction

Edit: Of course flattening the multicam clip works, but it's a destructive approach, which bothers me a bit...

Except...

... It does not work as a solution for multicam I'm trying to find some workaround for that as well, but no luck yet...

Thanks for the answer though, glad to know I might be heading the right direction

Edit: Of course flattening the multicam clip works, but it's a destructive approach, which bothers me a bit...

I think that as you explore a little further, you'll find that there isn't an exception when it comes to multicams. Multicams and compound clips (and I assume nested timelines, although I don't ever use those) all behave the same way with respect to the operations applied "on top" of them and "underneath" them. "Decomposing" a compound clip is the exact same thing as "Flattening" a multicam clip, and in fact, if you set up a keyboard shortcut for the "Decompose in Place" command, it'll work for both multicams and compound clips. You'll even see the same keystroke combination listed after the "Flatten in Place" menu commands.

But the thing to understand, is that when you apply any kind of operation to the outer shell, whether a multicam clip or compound clip, and then you discard the shell, the operations you applied to the shell also disappear. They don't "cascade" onto their contents. So, it's not multicams that are destructive, as you say. It's only the decomposing/flattening action that discards any information.

Here's an illustration by way of embarrassing personal anecdote: When I was a kid, my mom used to pack my lunch every day in a brown paper bag. Every day, she'd write "Jason's lunch" on the bag, with a hand-drawn smile. Of course, that wasn't the standard lunch packing technique employed by other kids' moms, so I got teased, and grew into a misanthropic A/V nerd, the rest is history. The point is: If I throw away the brown paper bag, I expect mom's note to go with it.

Another thing to understand is that the timeline scaling you're talking about is only one kind of operation out of a long list of possible operations which execute at the same stage (to simplify, a little). For example, if you apply a vignette to the whole multicam clip, then decompose it, the vignette will disappear as well.

It's funny that you use the term "precompose" in the youtube video. That term always bothered me in the After Effects world, and I always struggled to understand the order of operations it was meant to describe; having the option to leave "attributes in place" made it more confusing. It is essentially the same situation, which Adobe and BMD address differently. Adobe asks you which side of the fence you want to put your maths on, whenever you put up a new fence. BMD always puts the maths on your side of the fence, and assume you know where you're standing.

Man, that's so kindly written, it makes me slightly ashamed of my, let's say, a bit edgy style (partially caused by deadlining project not behaving as I would need it to ). Thank you for that, very nice!

It's decomposing/flattening them that's destructive.

Yeah that's what I actually meant, but maybe explaind my self poorly

Multicams and compound clips (and I assume nested timelines, although I don't ever use those) all behave the same way with respect to the operations applied "on top" of them and "underneath" them.

True, I'm starting to understand that now.

Overall, I think I know what you're saying and yes, you caught me red handed comming from Adobe stack and trying to approach different piece of software the same way

But at the end of the day, I still don't understand, why when I have a timeline, that is 4k, use it inside another timeline that is 2k, the first (4k) timeline acts like it is cropped to the second timeline's resolution. Shouldn't the first timeline just act as isolated piece of "footage", simply overlapping the smaller one, holding the ability to scale the whole 4k output as needed? I can imagine it can be frustrating for someone who understands the principles behind this, but I still don't...

But at the end of the day, I still don't understand, why when I have a timeline, that is 4k, use it inside another timeline that is 2k, the first (4k) timeline acts like it is cropped to the second timeline's resolution. Shouldn't the first timeline just act as isolated piece of "footage", simply overlapping the smaller one, holding the ability to scale the whole 4k output as needed? I can imagine it can be frustrating for someone who understands the principles behind this, but I still don't...

Man, I feel your pain. All of the questions you're asking are ones that I know I ranted about when I first came to these forums. I don't think you can look back through my posts, but if you could, you'd see. Rest assured; you're on the right track. The issues you're grappling with here stem from Resolve's "Resolution Independence," which is a major departure from the Adobe philosophy. I know you're under a deadline, but when you get a chance, you should look over chapter 9 of the user manual (p258), which explains it better than I can.

In the meantime, to get a 2K clip to scale up to a 4K container timeline, highlight the clip on the timeline, and in the inspector, under the "Retime and Scaling" category, if you alter the "Scaling" dropdown, it'll change the behavior you're talking about. "Fill" won't leave black bars, "Fit" will leave black bars, and "Crop" (poorly named, IMHO) doesn't scale anything, and keeps the original size relationship between the two, so it will only "crop" if the inner thing is bigger than the outer thing. In the opposite case, you'd see black bars on both the top and sides.

When you change the scaling behavior in the inspector, you're changing it on a per-clip basis. You can also change it project-wide, to save yourself some clicking, if you find yourself diving for that control in the inspector more often than not. To change the default scaling behavior at the project level, go to Project Settings->Image Scaling tab->Mismatched resolution files. The menu items here are a little more descriptive than the ones in the inspector, but they do the same thing.

Man, I feel your pain. All of the questions you're asking are ones that I know I ranted about when I first came to these forums. I don't think you can look back through my posts, but if you could, you'd see. Rest assured; you're on the right track. The issues you're grappling with here stem from Resolve's "Resolution Independence," which is a major departure from the Adobe philosophy. I know you're under a deadline, but when you get a chance, you should look over chapter 9 of the user manual (p258), which explains it better than I can.

In the meantime, to get a 2K clip to scale up to a 4K container timeline, highlight the clip on the timeline, and in the inspector, under the "Retime and Scaling" category, if you alter the "Scaling" dropdown, it'll change the behavior you're talking about. "Fill" won't leave black bars, "Fit" will leave black bars, and "Crop" (poorly named, IMHO) doesn't scale anything, and keeps the original size relationship between the two, so it will only "crop" if the inner thing is bigger than the outer thing. In the opposite case, you'd see black bars on both the top and sides.

When you change the scaling behavior in the inspector, you're changing it on a per-clip basis. You can also change it project-wide, to save yourself some clicking, if you find yourself diving for that control in the inspector more often than not. To change the default scaling behavior at the project level, go to Project Settings->Image Scaling tab->Mismatched resolution files. The menu items here are a little more descriptive than the ones in the inspector, but they do the same thing.

So, SO helpful Thank you very much and when this thing is done, I'm definitely checking out the manual chapter you're refferencing.

You made my deadline chasing weekend better, so maybe you're not such a misanthrope you might think after being teased because of the compound clips with name tag your mom was wrapping your original footage into

Thanks again, take care

Is there anything which prevents you from decomposing compound clips and nested timelines, to have available the original resolution?

That would be my suggestion as well.

Here's another thread to add to your list of people mentioning it before:
Resolution Independence not working?

To those saying that this is "how it is", I'd like to point out that Premiere Pro can handle nested timelines (sequences) of a higher resolution, and allows panning and zooming on them in an enclosing sequence, without cropping them. It doesn't support 'smart' resolution independence in that it doesn't combine multiple transforms - eg if Sequence1 scales MediaFile1 down to 10%, then Sequence2 nests Seq1 and zooms in 10x, MediaFile1 will look awful (assuming I didn't miss a setting). But at least it handles the basic case of nesting working across resolutions, something I have needed myself in the past and really wish Resolve would handle.

This is high on my list of wishes for v17: full support for nested timelines/compound clips, such that they reach feature parity with source media clips, including for resolution operations. I would love it to be possible to use any clip in place of any other clip and have it work seamlessly and intuitively, rather than the minefield of exceptions, glitches and annoyances we have today. And I'd love even more for Resolve's much-vaunted smart Resolution Independence - ie the combination of multiple transforms into a single one on the source media file - to also work with any amount of nesting, with any of the nested clip types.

The fact that any nested timeline-like clip shows a weird and nonsensical preview when "Center or crop" mode is used says to me that even if full resolution independence support in nested clips could be considered missing functionality rather than a bug, there are also definitely bugs in this area. Here's a very simple example:

In that example, the enclosing timeline is 1920x1080 and so is the Compound Clip, but the source media file is 720p, with Rescaling mode set to "Crop" so it doesn't get scaled. That results in the enclosing timeline seeing that strange preview, which is basically a small rectangle from the centre of the source media clip; as if Resolve has scaled the clip too many times.

Fortunately, in situations where the source media is a lower resolution, the actual output of the nested Clip is correct. So in this example, the 720p media file appears correctly in the 1080p enclosing timeline, centred and surrounded by black bars. Had the nested clip contained higher-resolution media (eg 2160p), then it would be cropped and unusable, as the OP described.

I can see no obvious reason why full support for nested clips shouldn't be possible. It should at least support what Premiere Pro does, and allow higher-resolution nesting without cropping. But ideally it should also be able to do that while maintaining the 'smart' resolution independence, and combine multiple transforms to maintain full image quality. Then Resolve would have a clear feature benefit over the competition.

It would significantly improve the flexibility of the software if we were able to use any amount of nesting, using any of the timeline-like clips (timeline, compound, Fusion, MultiCam), without losing functionality or getting weird issues and bugs, and I do hope this will be worked on at some point.

In the meantime there's a feature request thread that covers this and other points, if you want to add your +1 to it:
viewtopic.php?f=33&t=115706

As that thread describes, there are also a number of other glitches and annoyances related to timeline-like clips, such as: the inability to Deliver inside non-Timeline clips; not being able to Decompose In Place a Fusion Clip; not being able to Reconform From Bins to a Timeline target; a crash bug if you Reconform From Bins when targetting a Compound Clip with Loose Name matching; renamed Multicam and Fusion clips not using their new name outside the Media Pool; and more.

Yeah those are some good points! I think I'm starting to understand a few things after this thread got some answers. But there are still situations suggesting the timeline system is non completely healthy after all... Like...

The fact that any nested timeline-like clip shows a weird and nonsensical preview when "Center or crop" mode is used says to me that even if full resolution independence support in nested clips could be considered missing functionality rather than a bug, there are also definitely bugs in this area.

Exactly this! I noticed, that in some situations I was so confused by the resolution/cropping behavior, the previews actually showed what I would expect to happen to the timeline!

So I'm staying curious to see what future versions bring Fingers crossed

I'm not sure if this will help you, but finding your thread here led me to find a solution to a workflow that I needed as this issue really impacted my output method.

As you know resizing compound clips, multicam clips and fusion clips in nested timelines doesn't really work as you are forced to edit the contents of the compound clip when bouncing out versions. This really messes up my versioning pipeline when bouncing a master edit to social media in 4x5/9x16 crops as I can not leave the Multicam Clip untouched and work nondestructively. Or put another way, if I want to reframe for Social, any MC clip just can't be reframed unless I decompose.

Basically in FCPX and Premiere Pro I'm used to being able to nest MC or Compound Clips or AE Dynamic Linked animations and those applications allow for nesting and resizing while carrying through the full resolution of the compound clip to reframe in the new timelines.

After a little more research and testing, I think I have found the a solution!

Since having multiple timelines with various resolutions was new to R16 I assumed they would handle nesting in the same way FCPX and Premiere Pro do. But clearly they do not. The Compound Clip (MCs and Fusion Clips) respect the TIMELINE FORMAT Resolution you set when you create the timeline. But in R16 there is a new tab in the timeline settings for OUTPUT Resolution. Now the 3500 page manual explains that this Output resolution effects both monitor output and the deliver tab, allowing for multiple resolutions to be outputted as needed. What they don't explain is that you can apply any final aspect ratio or resolution to the Output settings when you uncheck "Use Timeline Settings for Output Scaling" allowing you to specify your delivery output resolution while maintaining the full res timeline settings. Or rather they don't really explain that you could use this method for reframing for social media. I am curious how this works in R17, but I have yet to test that update.

This method means that any MC's and Compound Clips including Fusion Clips carry through their full resolution in the timeline and can be reframed and scaled manually as needed to match your desired output resolution.

This allows me to work non destructively while creating dozens of versions while carrying through grades, comps and object replacements etc.

This should be the optimal workflow for outputting to Social Media Platforms but I can't find any tutorials or manuals that explain this. It's a different way of thinking, but this actually might be a better way to work long term as the working timeline and project resolution never change timeline to timeline, BUT your output resolution can, and the queuing exports in the render tab will be non the wiser.

I dare anyone to tell me this behavior is expected and correct. Don't even try to tell me I should resize the originals! What if I want to use the same footage more than once, each time with different "zoom" or position!?

That is the expected and correct behavior. You should resize the originals. If you want to apply different effects on different parts of the clip, don't nest.

I simply refuse to believe it's the correct behavior I'm so sorry, but I just do

The simplest way I can put my thoughts in text: Is it really correct behavior, when the timeline has different output when viewed separately from inserted when into another timeline? Because that's what's happening here.

For me it's not an expected behavior, at all.

It wasn't thought out properly when they integrated this a the beginning. Or it's simply bugs they never fixed.

I'll take the "Smart Object" of Photoshop as an example. We can put everything and anything in it, every effect, high res pictures, whatever, and when you manipulate this smart object, it acts like one "flattened" that you can manipulate as you which (it's more resource intensive but it's the goal of the Smart Objects).

"Smart Objects" are "nested layers". It outputs a "rendered frame", and we should be able to do whatever with this frame. And in Resolve's case, these frames. (I say that for people who are saying thing what Resolve does is "expected", when it's not)

Nested timelines (or compound clips) should behave EXACTLY the same IMO.

And it doesn't. It's very frustrating... My last problem with that was when I took a portion of a nested timeline to make a fusion comp out of it (before that, I was thinking about turning an adjustment layer into a fusion comp so it takes everything "below"... hey, it didn't render).

At the render stage, it just stops at the beginning of the comp, 0 fps rendering, and I have to force close Resolve. I'm sure it as to do with how Resolve is handling this nested timeline, and the fusion effects I'm putting on top of it.

It forces people to limit their creativity for to most illogical reasons. You think something very basic will work, you spend the time to do it... until you get into the render, and it doesn't render... BUT you can "render in place" fine, and you can play it (cached) in the edit tab just fine.

OH, and I almost forgot. Fusion... the last node is a single frame of everything before itself.. when you resize it or put any new nodes after it, you don't get weird cropping, color shifting of your previous node... and that is what's expected

OH MY GOD!!! @aaronvandomelen you are a GENIUS!! this is awesome.

We do a lot of 1:1 and this is the workflow i was looking so deperate. 16:9 multicam clips with out the crop in a 1:1 timeline. its a feature - not a bug. i love it.

now its possible to have an "adjustment clip" track (or possible group effect in color to turn of/on for reframes - without loosing all the edit info.

thanks so much

I suggest you test thoroughly before doing it that way. As far as I can tell Resolve does what it always has, it scales from the timeline resolution to the output resolution. So you won't be getting the original resolution.

I'd be happy to be proven wrong though. I tested with a UHD compound clip in a 720p timeline (Custom Timeline Settings > Format tab) with UHD output resolution (Custom Timeline Settings > Output tab).

On the Deliver page I let the Timeline Output Resolution dictate the render resolution, UHD. I rendered and compared with the original UHD compound clip in a UHD timeline. The difference is obvious.

The project timeline resolution was UHD, but as noted above I used custom timeline settings for each timeline.

I haven't tested multicam.

This should be the optimal workflow for outputting to Social Media Platforms but I can't find any tutorials or manuals that explain this. It's a different way of thinking, but this actually might be a better way to work long term as the working timeline and project resolution never change timeline to timeline, BUT your output resolution can, and the queuing exports in the render tab will be non the wiser.

You should do one and post in on the "regular" forum that would be great

Multicam in BMD is a joke.
Flattening is just a hack workaround to a poorly thought out Multicam workflow. Which is really just a Nested Timeline hack. Any scaling and color etc, should be applied to the Angle, not Multicam Container. Same for audio effects. One Cam may have boom, the other LAV. Yet any effects are applied to the Container and not the clip.

Yet another "PRO" issue not being addressed.

It's funny that you use the term "precompose" in the youtube video. That term always bothered me in the After Effects world,

This is a real pet peeve of mine. Pre-comping (and nesting in Adobe's world) confounds clip organization with a half-baked imitation of how nodes can route data arbitrarily while layers are sequential in nature. It's a mess. They started with Photoshop's layers and effects on layers and made Premiere and Slow Premiere (After Effects) in the same image. People then warp their brains around a kludgy workaround for making the world a place of layers and effect on layers.

Sort of like an entire nation changing their cuisine because the only tool they have is a hammer and so you have to be able to eat the food with a hammer.

Then once people try the more-direct, more-intuitive node-based approach -- which can still have hierarchical arrangement for organization, of course -- they get confused because their perception of what they're actually trying to do has been so badly warped.

Any scaling and color etc, should be applied to the Angle, not Multicam Container.

Color allows you to apply color correction, sizing, etc, to all the sub-clips of a single clip, all the clips from a single camera, or arbitrary combinations of clips live and at once. This is handled in a different manner from the Industry Standards of Avid and Adobe, so perhaps you should use them instead.

Fairlight allows you to apply real-time effects to arbitrary audio segments that are grouped into the same track. Again, this is not done in the Industry Standard Avid/Adobe way, so you should consider moving your production to Industry Standards if you do things in Industry Standard ways.

What they don't explain is that you can apply any final aspect ratio or resolution to the Output settings when you uncheck "Use Timeline Settings for Output Scaling" allowing you to specify your delivery output resolution while maintaining the full res timeline settings

They don't explain it because, as far as I can tell, the Output setting doesn't operate in the way you believe it does. The resolution limitations of compound clips you encountered earlier are still present; they're prior to the Output stage. Nothing in Output Scaling can change timeline operations which have already taken place.

As already noted above, you want to test this one thoroughly before proceeding on the assumption you're getting an original resolution which may not be there.

Any scaling and color etc, should be applied to the Angle, not Multicam Container.

The advantage of the current implementation is that we can do both. You just have to understand how things work, and it's easy.

I suggest you test thoroughly before doing it that way. As far as I can tell Resolve does what it always has, it scales from the timeline resolution to the output resolution. So you won't be getting the original resolution.

I'd be happy to be proven wrong though. I tested with a UHD compound clip in a 720p timeline (Custom Timeline Settings > Format tab) with UHD output resolution (Custom Timeline Settings > Output tab).

On the Deliver page I let the Timeline Output Resolution dictate the render resolution, UHD. I rendered and compared with the original UHD compound clip in a UHD timeline. The difference is obvious.

The project timeline resolution was UHD, but as noted above I used custom timeline settings for each timeline.

I haven't tested multicam.

I've tested this in the context that I have never had a need to work with UHD footage in a 720p timeline, then bounce out a UHD file. My workflow has generally been to work in the native resolution of the media (usually base on the A camera of course, but every project is different). So for my recent projects I have been shooting 4K DCI and editing in 4K DCI. The trouble I encountered revolved around bouncing the many many outputs to social for versioning. 1x1, 4x5, 9x16, 16x9, 2:1, and so on. When I had to create multiple timeline versions I found scaling issues with fusion clips, text, and multicam clips when scaling from 4K DCI to 1080x1350 or 1080x1080. However, when I duplicated the timeline, kept the timeline settings the same but changed the output settings to the lower resolution, the output was evenly downscaled to fit as needed. The output settings even include a scaler setting if you did need to upscale. Based on all of the tests I have done (especially with vector logos and text) I have seen clean lines and clean downscaling.

It seems obvious to me that if I imported 4k footage into an HD timeline, then attempted to bounce an 4k output, the chain scale would fail as it looks to be that the timeline settings scale first, with the output settings scaling last in the chain.

Like you said, the timeline resolution dictates the scaling and original resolution of the output. So for my workflow that's ideal. Instead of changing the timeline resolution for every output, I just change the duplicated timeline's output resolution. The timeline resolution keeps everything reading the full resolution correctly, included multicam clips and fusion clips, text etc. And only the output downscale resolution impact the final render. This also allows me to pan and scan as needed right in the timeline display without resorting to black bars or safe guides.

OH MY GOD!!! @aaronvandomelen you are a GENIUS!! this is awesome.

We do a lot of 1:1 and this is the workflow i was looking so desperate. 16:9 multicam clips with out the crop in a 1:1 timeline. its a feature - not a bug. i love it.

now its possible to have an "adjustment clip" track (or possible group effect in color to turn of/on for reframes - without loosing all the edit info.

thanks so much

No problem, so far it's working really well for me. I also like the fact that in my mastering timeline, let's say for the YouTube upload etc. I can work in the aspect ratio dictated by the project as well. Since I like to master in 2:1 more and more these days with online projects I can crop to that on the master timeline in the uhd output settings while keeping the native data in tact with the timeline settings.

I suggest you test thoroughly before doing it that way. As far as I can tell Resolve does what it always has, it scales from the timeline resolution to the output resolution. So you won't be getting the original resolution.

I'd be happy to be proven wrong though. I tested with a UHD compound clip in a 720p timeline (Custom Timeline Settings > Format tab) with UHD output resolution (Custom Timeline Settings > Output tab).

On the Deliver page I let the Timeline Output Resolution dictate the render resolution, UHD. I rendered and compared with the original UHD compound clip in a UHD timeline. The difference is obvious.

The project timeline resolution was UHD, but as noted above I used custom timeline settings for each timeline.

I haven't tested multicam.

I've tested this in the context that I have never had a need to work with UHD footage in a 720p timeline, then bounce out a UHD file. My workflow has generally been to work in the native resolution of the media (usually base on the A camera of course, but every project is different). So for my recent projects I have been shooting 4K DCI and editing in 4K DCI. The trouble I encountered revolved around bouncing the many many outputs to social for versioning. 1x1, 4x5, 9x16, 16x9, 2:1, and so on. When I had to create multiple timeline versions I found scaling issues with fusion clips, text, and multicam clips when scaling from 4K DCI to 1080x1350 or 1080x1080. However, when I duplicated the timeline, kept the timeline settings the same but changed the output settings to the lower resolution, the output was evenly downscaled to fit as needed. The output settings even include a scaler setting if you did need to upscale. Based on all of the tests I have done (especially with vector logos and text) I have seen clean lines and clean downscaling.

It seems obvious to me that if I imported 4k footage into an HD timeline, then attempted to bounce an 4k output, the chain scale would fail as it looks to be that the timeline settings scale first, with the output settings scaling last in the chain.

Like you said, the timeline resolution dictates the scaling and original resolution of the output. So for my workflow that's ideal. Instead of changing the timeline resolution for every output, I just change the duplicated timeline's output resolution. The timeline resolution keeps everything reading the full resolution correctly, included multicam clips and fusion clips, text etc. And only the output downscale resolution impact the final render. This also allows me to pan and scan as needed right in the timeline display without resorting to black bars or safe guides.

I just tested it! It's great! Thanks for the tips

Did anyone find a solution. I agree this is entirely deranged, this is my post about it :
viewtopic.php?f=21&t=175624