Existential Question: Project Resolution and Input Scaling

We know Resolve's Project Resolution setting can be lowered to enable the processor load to be reduced. This change can be made during editing. These changes should only affect the frame-size of processed effects. Small frames, I assume, create visibly lower quality images while one is editing. T/F?

What advice should be given in regards to the Initial Project Resolution setting? Perhaps the setting should be renamed--Target Processing Resolution. Or, perhaps, Processing Quality: High, Medium, Low and let Resolve figure it out. AI?

When we import clips, depending which of four settings are selected in the Input Scaling setting, a comparison is made between the current Project Resolution and a Source clip's resolution. Depending on the result of this comparison, the source clip may or may not be cropped or scaled.

I think this means there is an interaction between the current Timeline resolution and what is done or not done to source clips.

If our initial Project Resolution in combination with the Input Scaling setting affects what's done to imported source clips--then doesn't this affect export quality?

No matter our Project Resolution, if while editing we decide to change the Project Resolution setting, might that not change interact with with the Input Scaling setting?

My, perhaps, needless worries would be gone if there were a fifth Input Scaling setting which ignored a source clip's or a graphic's resolution.

Will checking Override input scaling and selecting None (the only choice) prevent Input Scaling?

What advice should be given in regards to the Initial Project Resolution setting?

Choose the highest resolution you will need to Deliver. (There are better ways to improve performance than changing timeline resolution.)

doesn't this affect export quality?

It does indeed, so the timeline's resolution should be at the highest resolution you will need to deliver before you actually deliver it.

(It's no problem going from a UHD timeline to an HD export. But don't do the reverse.)

The caveat here is that it's possible that changing the timeline resolution has undesired consequence. Hence the initial advice above.

1: it's not Project resolution that can be lowered, it's Timeline resolution.
For an overview of resolutions and sizing, see Chapter 141: Image Processing Order of Operations, page 3127 in the July 2023 18.5 reference manual.

2:

"These changes should only affect the frame-size of processed effects".

No. When you change Timeline resolution to your final delivery, all processing happens at the selected resolution (I ignore cached/proxy settings because I don't know how they interact and I don't use them)
3:

Small frames, I assume, create visibly lower quality images while one is editing.

Yes. When editing, where speed is more important than quality, lower resolution means lower quality.
When rendering, where quality is more important than speed, higher resolution is needed.

4:

"What advice should be given in regards to the Initial Project Resolution setting?"

(again, should be Initial Timeline Resolution) Use the highest resolution, up to and including your delivery resolution that you can live with, with the current hardware at your disposal.

5:

"I think this means there is an interaction between the current Timeline resolution and what is done or not done to source clips."

Correct. If there is a mismatch, then scaling is applied. Your choice is how that scaling is applied.
See Chapter 6, Page 137.

6:

No matter our Project Resolution, if while editing we decide to change the Project Resolution setting, might that not change interact with with the Input Scaling setting?

Change the destination resolution forces a resizing of the input media, that seems obvious.
Source media: x*y resolution, Timeline resolution a*b. To get from x*z to a*b, a scaling factor (k and l) is applied, so x*k=a and y*l=b. How k and l is chosen is dependent on the Input Scaling setting.

7:

My, perhaps, needless worries would be gone if there were a fifth Input Scaling setting which ignored a source clip's or a graphic's resolution.

. How would that work? Every piece of media* has a pixel dimension (* I'm ignoring vector graphics here, but even then, in order to view vector graphics it needs to be rasterized, eg turned into pixels). So it makes no sense to have dimensionless anything, the concept itself makes no sense.
But if it makes you feel better, here's the "do nothing" setting:

Center crop with no resizing: Clips of differing resolution are not scaled at all.

8:

Will checking Override input scaling and selecting None (the only choice) prevent Input Scaling?

no. Only choosing "Center crop with no resizing" will do that.
The Override Input Scaling presets are documented at Chapter 150 Sizing and Image Stabilization, page 3312.

So, to summarize:
Chose the timeline resolution that gives you the speed you want, change timeline resolution before rendering (if you forget, Davinci will warn that the timeline resolution is lower than the delivery resolution. If that's the case the Output sizing algorithm is employed).
Scaling happens if there is a mismatch, unless selected not to scale.

I would add to what Mads has noted that, contrary to the repeated claims of some here, there is not a better way to improve overall editing performance than temporarily reducing timeline resolution. The alternatives are unwieldy and time-consuming, and best regarded as last resorts.

1: it's not Project resolution that can be lowered, it's Timeline resolution.

Correct

But if it makes you feel better, here's the "do nothing" setting:

Center crop with no resizing: Clips of differing resolution are not scaled at all.

18.6 documentation says:
Center crop with no resizing: Clips of differing resolution are not scaled at all. Clips that are smaller than the current frame size are surrounded by blanking, and clips that are larger than the current frame size are cropped.

Sorry brain fart late last night so I misread. You are correct this will work even if the current frame size changes. Oddly, this is the setting I have always used.

In terms of advice: As I understand it, Timeline resolution does not set Timeline resolution because Resolve has no such thing. The setting establishes a frame-size that defines the maximum processing image resolution for FX, etc. By setting it low initially or by lowering it while editing, one limits the maximum processing load hence preventing stuttering during playback. And, when it limits maximum processing load during editing it may degrade image quality.

Sorry brain fart late last night so I misread. You are correct this will work even if the current frame size changes. Oddly, this is the setting I have always used.

Happens to the best of us

In terms of advice: As I understand it, Timeline resolution does not set Timeline resolution because Resolve has no such thing. The setting establishes a frame-size that defines the maximum processing image resolution for FX, etc. By setting it low initially or by lowering it while editing, one limits the maximum processing load hence preventing stuttering during playback. And, when it limits maximum processing load during editing it may degrade image quality.

Say that again slowly please: Timeline resolution does not set Timeline resolution.


Timeline resolution sets Timeline resolution.


I don't know how to make that clearer.

Chapter 6, page 130 has the following text:

Timeline resolution: A drop-down menu that lets you choose a frame resolution preset to use
for image processing while grading. DaVinci Resolve is resolution independent, so you can change
the resolution at any time and all windows, tracks, sizing changes, and keyframe data will be
automatically recalculated to fit the new size. For example, you can work on a 4K project while
monitoring at HD resolutions if your room is only set up with an HD monitor, and then render the
finished project at 4K resolution for final delivery. Alternately, you can downsize an HD project
to an SD resolution to create another set of deliverables. For more information on Resolve’s
resolution independence, see Chapter 150, (page 3308) “Sizing and Image Stabilization.”

As a broad overview, I think the following steps show how a movie is edited:
1.0) Media has a known resolution
1.1) Media is added to project
1.2) Timeline is created with media resolution AND/OR intended delivery resolution
2.0) User discovers editing speed is too slow
2.1) User changes timeline resolution to lower numbers
2.2) User edits
2.3) User is done editing
2.4) User changes timeline resolution back to the setting in point 1.2
3.0) Timeline is rendered at delivery resolution.

I suspect you might have missed point 2.4 or that, when rendering at point 3.0, all processing is done again* (*: again, assuming no cache/proxy is used)


This is all very high level and I'm not sure it's what you need. What specific problem do you have?

We know Resolve's Project Resolution setting can be lowered to enable the processor load to be reduced. This change can be made during editing. These changes should only affect the frame-size of processed effects. Small frames, I assume, create visibly lower quality images while one is editing. T/F?

What advice should be given in regards to the Initial Project Resolution setting? Perhaps the setting should be renamed--Target Processing Resolution. Or, perhaps, Processing Quality: High, Medium, Low and let Resolve figure it out. AI?

When we import clips, depending which of four settings are selected in the Input Scaling setting, a comparison is made between the current Project Resolution and a Source clip's resolution. Depending on the result of this comparison, the source clip may or may not be cropped or scaled.

I think this means there is an interaction between the current Timeline resolution and what is done or not done to source clips.

I will cut to the chase and give you some anecdotal advice.

When we sit down to start a job, what I generally do is consider the delivered resolution of the final project. Aspect ratio is a consideration, size is a consideration, letterbox/full-frame is a consideration. We traditionally will bring in the files in 1920x1080, assuming a 3840x2160 final delivery. As long as the aspect ratio does not change, there shouldn't be any window tracking or sizing problems. You do have to be careful to watch out for mixed resolution files, like throwing 5K or 6K or even 8K into the timeline, and be prepared to adjust and reframe when necessary.

We also make sure that when the final render is done, we use the maximum Full Res Premium decoding in the Camera Raw settings, as well as Force Sizing to Highest Quality and Force Debayer to Highest Quality in the final render. And of course, switch the Timeline settings to 3840x2160 (or whatever the appropriate delivery size is).

I don't think there's an A.I. solution per se, because you have to just have the experience to know what the client expects, and you have to have a good enough grasp of workflow to be able to give them what they need. There's always the chance they'll need multiple deliverables -- for example, a 4096x1716 scope 4K theatrical version, as well as 1920x1080 HD versions for streaming or previews.

I think the key to remember is: don't get caught in a situation where you've worked on a show in HD, it comes time to deliver in 4K, and you forget to change the Timeline Settings back to 4K. For the last few Resolve versions, they now pop up a warning version warning you that you're uprezzing the session higher than the original source resolution. If you see that, stop what you're doing, check everything, and make sure everything is reset to the appropriate sizing.

The whole chapter in the manual on "Input Sizing and Resolution Independence," scaling, and the various settings is a mission critical section you need to read TWICE to understand. It's particularly important when you're dealing with an unusual aspect ratio. Lots of very important information there. You have to understand what's going on in order to diagnose problems like this and figure out how to eliminate all borders from the image. This is one of those things that's very easy to screw up in the initial project setup and in the final delivery.

I traditionally will do a 1-minute test render and then check the render in the OS to make sure the sizing is exactly what I need it to be. And I create sizing charts prior to start of picture so I can verify, "yes, nothing is being cut off and everything is fine."

[quote="Mads Johansen"][quote="SteveMullen"]
Sorry brain fart late last night so I misread.

Say that again slowly please: Timeline resolution does not set Timeline resolution./quote]

That was a joke to point-out that Resolve doesn't work like other editors where one establishes a timeline resolution and that's it. It's the next sentence that's important.

The setting establishes a frame-size that defines the maximum processing image resolution.

I'm taking the liberty of changing this to Full Quality Playback Timeline Resolution or FQPTR.

When one sets a FQPTR value as long as the frame-size is equal to this value then (A) and/or (B) will be true:

A=the timeline will play at the correct rate
B=when image(s) are processed (i.e., an opacity calculation) the processing will be at full resolution, i.e. full quality.

When clips larger than 1080p are encountered, the playback frame rate will not be able to be maintained and/or image quality will suffer.

Example: set FQPTR to 1920x1080. Images that are 1920x1080 will play at the correct rate and with 1080p resolution.

When clip(s) are smaller than FQPTR and you don’t want these clips to be upscaled, set Input Scaling to Center crop with no resizing.

When clip(s) are smaller than FQPTR and you want these clips to be upscaled, set Input Scaling to Scale entire image fit frame to fit.

Sorry brain fart late last night so I misread.

Say that again slowly please: Timeline resolution does not set Timeline resolution

That was a joke to point-out that Resolve doesn't work like other editors where one establishes a timeline resolution and that's it. It's the next sentence that's important.

The setting establishes a frame-size that defines the maximum processing image resolution.

I'm taking the liberty of changing this to Full Quality Playback Timeline Resolution or FQPTR.

When one sets a FQPTR value one assumes/expects/hopes that as long as the frame-size is equal to or lower than this value then (A) and/or (B) will be true:

A=the timeline will play at the correct rate
B=when image(s) are processed (i.e., an opacity calculation) the processing will be at full resolution, i.e. full quality.

Example: set FQPTR to 1920x1080. Images that are 1920x1080 or smaller will play at the correct rate and with 1080p resolution.

When clips larger than 1080p are encountered, the playback frame rate will not be able to be maintained and/or image quality will suffer.

I don't see a question here.
Did you read the chapters we pointed out?

If you set timeline resolution at 1080p and insert images that are 1920x1080, they will be shown unscaled.
If you set timeline resolution at 1080p and insert smaller images, they are either put in with black bars, scaled or stretched to match 1080p.
If you set timeline resolution at 1080p and insert larger images, they will be put in unscaled (with content outside of the 1080p image), cropped, scaled or stretched (actually the reverse of stretched, which I don't know the word for).
If you have images larger than 1080p images and want full use of the images resolution, use a timeline resolution that is as large as the image (with all the associated effects).

I don't see how it's more complicated than that.

That was a joke to point-out that Resolve doesn't work like other editors where one establishes a timeline resolution and that's it. It's the next sentence that's important.

Well, there's a point when you have to stop comparing Resolve to the previous editing systems you've used, and instead embrace the way Resolve actually works. Basically: stop fighting it, adopt a Zen approach, and just deal with how it actually functions.

I left out the important page: the chapter you need to read is, Chapter 11, "Image Sizing and Resolution Independence," starting on p. 269 of the 16.5 manual. I can't emphasize enough the importance of this in the manual, particularly on how Resolve deals with Mismatched Resolution Files.

There's a lot of situations where you can have Timeline Resolution set to one thing, but do 3 renders in a row set for three completely different delivery resolutions: for example, a 4K timeline that renders at 40962160, then at 3840x2160, then at 1920x1080. (I haven't tried this, but it can be done.)

I generally go over and manually set the timeline resolution to whatever I need to render, render that, and then switch over to whatever I need for other deliverables. The reason why is, I want to take a look at a few minutes of each version and make sure there's no issues with graphics being reframed, the wrong letterbox blanking being applied, or some other bit of minutia that goes wrong. You really have to stay on top of it, and there's no shortcuts for that. The good news is: it can be flawless and perfect and simple to deal with once you understand how it works.

[quote="Mads Johansen"
I don't see a question here.[/quote]
There is no question. I'm explaining how it works. You then also state how it works.