I’m using Topaz 1.2.1. I have observed this behavior in 1.2.0 and 1.2.1. The Starlight Sharp model does not respond properly when told to perform a 3x or 4x upscale.
Repro:
User imports video (640x480, for simplicity’s sake)
User sets output to a 3x upscale from Starlight Sharp. Starlight Mini does not have this problem.
User requests output as a series of images
Expected Behavior:
Topaz Video creates a series of images at 1920x1440 resolution.
Actual Behavior:
Topaz video creates a series of images as 1440x1080 resolution, even when told to use the video’s original pixel size. This happens at both 3x and 4x resolutions.
Adding to the oddity is this: The 2x and 3x upscales are visually slightly different, implying that TVAI is doing something differently. The 3x is also slightly slower than the 2x, though not as much as it should be. The 4x and 3x upscales, however, look identical, output the same 1440x1080 resolution, and take the same amount of time per frame to render.
I’ve checked the issue across multiple videos and it’s the same in every case. 640x480 is turned into 1280x960 (if 2x is selected) or 1440x1080 (if 3x or 4x are selected) as opposed to 1920x1440 or 2560x1920.
Outputting to video instead of frames doesn’t make a difference. I tried ProRes and the system is creating a 1440x1080p video even though I set to a 3x upscale from 640x480 with square pixels. It should be targeting 1920x1440 for 3x w/ square pixels or 2160x1440 for 3x with non-square pixels.
Again, this issue only appears to affect Starlight-Sharp. Starlight Mini behaves as-expected.
Well, that does seem to answer part of the question – but only part of it. Specifically, the document you linked states:
“The following available outputs:
1x (Native resolution)
1920x1080 (FHD)
3840x2160 (4K UHD)”
I can’t speak for what other people see, but when I select “Starlight Sharp,” I get the same set of options as Starlight Mini:
Minimum
2x Upscale
3x Upscale
4x Upscale
In the current system, 1x and 2x create identical output, while 3x and 4x both target 1080p as opposed to 3x delivering 1440x1080 and 4x producing 2880x2160. The page, as written, does not accurately describe observed behavior.
“Minimum” does not produce 1x 640x480 output. It claims it will output 1280x854, but it actually outputs 1280x960 – a 2x upscale.
Choosing 2x for 640x480 properly outputs 1280x960. This option isn’t even covered on the page you link, but the 1x and 2x outputs are identical in quality and resolution.
4:3 content set for a 3x upscale is shifted to a 1080p width – so that somewhat matches – but
4x content that ought to target 2880x2160 if the link you shared was accurate is identical in output and resolution to the 3x content.
Finally, identical output between 1x / 2x and 3x/ 4x does not match the description of three distinct resolution targets as written on that page. There is no sign of a Nyx variant being deployed at 4x. If the difference between 1x / 2x and 3x/4x is Nyx, Nyx is targeting both the nominal 1080p setting and the “4K” setting (that isn’t being output at 4K).
I do appreciate the link – I hadn’t seen it before – but it does not explain the model’s observed behavior or the difference between claimed output resolutions and actual output resolution as measured in each mode.
Looking into this and having the team update the docs page to provide updated details on how the model works. Those original resolution limits were from when the model was first released and was not updated correctly. Thanks for catching that.
The document is wrong, was not edited. For 4:3 aspect ratio sources at 480p, using the minimum SLS/SLM setting outputs 960p. The same result occurs when applying 2× scaling, because 960p is the model’s minimum output for 4:3 content.
For 16:9 sources at 480p, the minimum output is 720p, while applying 2× scaling produces 960p.
You can also “cheat” by adding left and right letterboxing to a 4:3 source to make it 16:9. If you feed this into Topaz, it will output 720p; afterward, you can crop the letterboxing away.
It would be really helpful if Topaz gave us more flexibility regarding the output resolution, as the models are capable of it.
“You can also “cheat” by adding left and right letterboxing to a 4:3 source to make it 16:9. If you feed this into Topaz, it will output 720p; afterward, you can crop the letterboxing away.”
To be clear: I can’t get Starlight-Sharp to output anything above 1280x960. I hear you on the 16:9 frame and agree it would work, but it doesn’t enable the 3x upscale model I wanted to test. I don’t really count the odd 1440x1080, because it’s stretching 640x480 by 2.25x to get there and I’m guessing it’s just performing a 2x upscale with an image resize.
In testing, I’ve found that 3x – 1920x1440 – actually works quite well for 640x480 when using Starlight-Mini, if one can stand the performance hit.
hmm this is strange, I could ever do more than 960p with SLS, since release..but i never get 1440x1080 out with a 480p source, it does always 720p (minimum when it’s 16:9) or 960p (2x) or 1440p (3x) Maybe reinstall or try previous version? Sorry I must ask; have you checked output with MediaInfo? Shown resolution in Topaz running output window is sometimes wrong.
1x and 2x look identical. 3x and 4x look identical to each other but slightly different from 1x/2x. I’m guessing the slight variation is the application of whichever image resize algorithm Topaz uses to move from 2x to 2.25x.
Now, I did have Topaz 7 installed on this system at one point before I decided to subscribe, so it’s possible that’s throwing something off, but I’ve had multiple versions of TVAI installed before without any problems, so I’m unsure.
I was just able to replicate this with a 640x480 source as well and shared the details with the devs for investigation.
We saw some similar situations with SL Mini when using lower resolution videos and the model’s minimum resolution size that the research team is still looking into.
