FS7: Round-Tripping & Loss of Detail

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digitalinnovations

Well-known member
Hello all!

So this would probably apply across the board but I noticed on a recent project a loss of detail when round-tripping from FCPX > Resolve > FCPX and I’m wondering what would be “best / better practices”. Here’s the workflow as it sits...

- Shot in XAVC-I, S-Log3.cine, 4K DCI
- Import into FCPX
- Rough Cut in FCPX
- Export XML to Resolve
- Color / Grade
- Export ProResHQ 4K DCI
- Final edit tweaks, etc. in FCPX
- Export 1080 ProRes HQ

What I’ve noticed is the 1080 master out of FCPX actually looks softer than the 4K exported from Resolve...shouldn’t the perceived sharpness be higher since it is going from 4K > FHD? If nothing else I would think it would at least equal. What am I missing? Hopefully someone has some “pointers” to help me maintain the best possible quality throughout the process.

I know some might suggest just doing everything in Resolve but editing is just so much faster/smoother in FCPX. Resolve is still sluggish for me (and rightfully so I guess once you’ve burdened it with the grade nodes) and one of the biggest issues is also that audio is not smooth and that makes cutting dialogue very difficult. If Resolve would playback as smooth and consistent at FCPX I would love to do that but until that day OR I’m ready spend serious dollars to upgrade my system this is where I’m at.

I appreciate your time to read and any advice!
 
Cary Knoop said:
Wait, are you asking why reducing the resolution from 4k to 1080 causes a loss of detail? :huh:
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I actually am, Cary, crazy huh?

Obviously when going from 4K > FHD you're losing resolution size but I wouldn't think it would make the footage appear...I don't want to say "soft" but if you look at them side-by-side you can see that the FHD is definitely soft-ER. If anything, isn't it widely accepted and/or touted that one of the benefits of shooting 4K for an HD master is the increase in (perceived or otherwise) sharpness/detail?

Just FYI in case I'm doing something wrong (and I want to know if I am) to compare the outputs I've opened both the FHD master exported from FCPX and the 4K version exported from Resolve in QuickTime and reduced the size of the 4K to match and the difference is quite easily noticeable. Now I may be incorrect but I would think a rendered and exported master file from FCPX should have better scaling/processing than QuickTime can do "on-the-fly" on it's own BUT isn't this "scaling" I'm doing when viewing these in QuickTime essentially the same thing I am doing in FCPX when I drop this 4K footage in a 1080 timeline? So shouldn't I see similar results?
 
Publimix said:
You know of course you have to 'sharpen' Cine-slog files in post. Maybe the problem starts there.
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Up to this point (over a couple years now) I haven't sharpened any of the footage out of my FS7 but this whole "thing" has actually encouraged me to start researching "best practices" for sharpening in Resolve. Please if you have any tips/tricks/advice please share - especially since it would be specifically geared towards S-Log and the FS7.

All that said...but wouldn't you think that the 4K > FHD Master would have at least the same amount of detail/sharpness as the source footage without sharpening?
 
4K is four times the resolution of FHD. 4K HAD BETTER look more detailed than FHD. What I think you are referring to, is the fact that a clip shot in 4K and down-scaled to FHD will look better than if the same scene were shot at FHD to begin with. I heard it this way before getting into 4K and once I got my first 4k camera I was able to confirm that this is definitely true. Sharpening is not adding pixels, it's an artificial way of making images appear more crisp. I don't know how to explain that technique except to say the process seems to involve making the boundaries between adjoining colors have a higher contrast, so rather than a gradual bleed off in colors where the two meet, it's more of an abrupt change.

I don't use FCPX, I use Vegas Pro 13 and 15, so I can't help about your round-trip process. For Vegas, I shoot 4k and edit on a FHD timeline. If I do a crop/pan of the 4K clip, I try not to go below 2200 (from the original 3840). Any lower than 2200 and my final FHD renders will not look any better than if I shot in FHD to begin with. But the more above 2200 I stay, my video quality surpasses what I would get if I shot in FHD originally (and did not crop in post).
 
digitalinnovations said:
Up to this point (over a couple years now) I haven't sharpened any of the footage out of my FS7 but this whole "thing" has actually encouraged me to start researching "best practices" for sharpening in Resolve. Please if you have any tips/tricks/advice please share - especially since it would be specifically geared towards S-Log and the FS7.

All that said...but wouldn't you think that the 4K > FHD Master would have at least the same amount of detail/sharpness as the source footage without sharpening?
Click to expand...

All I know is that CINELOG doesn't sharpen the images 'in camera', so you have to do it in post, as far as I know. So what I usually do is use the sharpen tool in Davinci and set it (radius) at 0.47. (This tool can be found in the color page).
 
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I just said this to someone else, but IMO...

For the best quality: Shoot in 4K / Edit in 4K. Period.

Industry-standard practices in which you hear about people mastering in 2K are coming from $50,000+ cameras via processes you probably don't have access to.

For everything else, if you want the best results and you're shooting in 4K with your prosumer camera...edit in 4K and upload in 4K for the sharpest results (again IMO), or at least master in 2K/HD FROM your 4K file.

The lowest-quality results from my own experiences have always come from throwing my 4K footage into a 2K/HD timeline. You will find that doing that does provide you better HD than if you had originally shot in HD (as mentioned above), but it also depends on the camera.

Some cameras have weak 4K, but produce super-sampled 444 HD that looks tremendous.
 
Publimix said:
All I know is that CINELOG doesn't sharpen the images 'in camera', so you have to do it in post, as far as I know. So what I usually do is use the sharpen tool in Davinci and set it (radius) at 0.47. (This tool can be found in the color page).
Click to expand...

Great! I’ve read a little about making qualifiers for the sharpening, etc. so that’s why I wondered what your process was but that sounds very straight forward and .47-.48 was sort of where I was landing on first impressions. Thank you, sir.
 
Not at all being argumentative (I am the one asking these questions to everyone after all) but just looking for some clarification...

NorBro said:
I just said this to someone else, but IMO...For the best quality: Shoot in 4K / Edit in 4K. Period.
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But when you’re delivering for broadcast that isn’t really an option...as of now..at least in my area.

Then you could say “why not shoot HD then?” but I would answer, “the flexibility of 4K acquisition for HD mastering - reframing, stabilization and (what I thought until now) even more crisp HD than what can be done real-time, in-camera.”

NorBro said:
For everything else, if you want the best results and you're shooting in 4K with your prosumer camera...edit in 4K and upload in 4K for the sharpest results (again IMO), or at least master in 2K/HD FROM your 4K file.
Click to expand...

This is where I’m looking for the clarification...isn’t that exactly what we’re doing by dropping our 4K footage (files) into an edit and exporting a 1080 master? Or is there some other “middle step” you’re eluding to?

NorBro said:
The lowest-quality results from my own experiences have always come from throwing my 4K footage into a 2K/HD timeline. You will find that doing that does provide you better HD than if you had originally shot in HD (as mentioned above), but it also depends on the camera...Some cameras have weak 4K, but produce super-sampled 444 HD that looks tremendous.
Click to expand...

I guess it’s all subjective but I wouldn’t think most would classify the FS7 as prosumer or producing “weak” 4K...although definitely not an Alexa...still a fairly decent camera system.
 
One quick update on my original issue / question: I didn’t have time today to dig much deeper but I have found that there is definitely an issue (at least on my system) with scaling 4K > 1080 within FCPX.

To test my theory, I let Resolve do the 4K > 1080 downscale upon export, then relinked the footage in FCPX and exported my master...the results were noticeably more sharp (or detailed, crisp...whatever word you prefer) than when I allowed FCPX to do the 4K > 1080 downscale.

What’s more, when I compared the 1080 files out of Resolve to the master export from FCPX there was *still* a degradation of detail - why?? - it is slight but you can see it. There were no adjustments or filters or scaling (1080 footage on a 1080 timeline) or anything of any kind other than trimming / tightening up a few of the edits and mixing the audio and everything throughout the pipeline was ProResHQ.

Very odd.
 
Those are all good questions...

- For broadcast, you have no choice. And no one is airing your content in 4K so it doesn't really matter. I was just thinking Vimeo/YouTube for any viewer who chooses to watch it in its highest quality.

- Over the years, I've learned that processing differs from software to software. We all know that some programs just do things better than others and it's the same with exporting files. From my experience, I preferred the way my HD files looked from 4K masters. I can't explain why, but my theory is that a HD file produced from a 4K master (which has all of the resolution) just looks better vs. exporting a HD file from 4K footage that's in a HD timeline and has lost information from being there.

Not sure if that makes sense and again it might depend on the camera, or the exporting process/software...but just my opinion.

- I wasn't referring to the FS7 as having weak 4K...just in general. Not that weak means it looks bad...just that some cameras will shot 8-bit 4K 4:2:0 but their HD might be available in 10/12bit 422/444.

---

What I recommend you should do is export a few files and pixel-peep the results for days and determine what looks best.

Maybe different variations...

(1) Edit in a 4K timeline in FCPX and export/share from FCPX.

(2) Edit in a 4K timeline in FCPX and send to compressor and choose various formats from there.

(3) Edit in a HD timeline in FCPX and export/share from FCPX.

(4) Edit in a HD timeline in FCPX and send to compressor and choose various formats from there.

(5) Do your normal workflow/Resolve round-trip and compare that.

(6) Maybe only edit in a 4K timeline in Resolve and see what that looks like.

(7) Maybe only edit in a HD timeline in Resolve and see what that looks like.

(8) Then maybe try other software, lol.

Personally, I am extremely neurotic and would try as many combinations as possible. There are more technical people that can describe what is happening to your pixels or bits or colors, etc. when you are working within various resolutions, but I don't consider it...I just know that my 4K footage does not look right coming from a HD timeline.
 
digitalinnovations said:
One quick update on my original issue / question: I didn’t have time today to dig much deeper but I have found that there is definitely an issue (at least on my system) with scaling 4K > 1080 within FCPX.

To test my theory, I let Resolve do the 4K > 1080 downscale upon export, then relinked the footage in FCPX and exported my master...the results were noticeably more sharp (or detailed, crisp...whatever word you prefer) than when I allowed FCPX to do the 4K > 1080 downscale.

What’s more, when I compared the 1080 files out of Resolve to the master export from FCPX there was *still* a degradation of detail - why?? - it is slight but you can see it. There were no adjustments or filters or scaling (1080 footage on a 1080 timeline) or anything of any kind other than trimming / tightening up a few of the edits and mixing the audio and everything throughout the pipeline was ProResHQ.

Very odd.
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Just seeing this...seems like you've already started, lol.
 
Does the fs7 with a decent lens need sharpening in camera..? regardless of gamma curve.. if its anything like the f5 is too sharp without anything being added..
 
Donny 123 said:
Does the fs7 with a decent lens need sharpening in camera..?
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Yep for Slog which does not sharpen.

--

Of course ones chosen look is entirely subjective. But in my minimal knowledge of digital imaging, debayer.. aka inventing data to fill in holes in the image (ie no red data recorded in a blue pixel etc.) then sharpening is part of the 'normal' process.
 
NorBro said:
... From my experience, I preferred the way my HD files looked from 4K masters. I can't explain why, but my theory is that a HD file produced from a 4K master (which has all of the resolution) just looks better vs. exporting a HD file from 4K footage that's in a HD timeline and has lost information from being there...
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Ah-ha...I think this is where we had our "disconnect". I think you are saying you prefer to edit in 4K and export a master (ProRes or equivalent) in 4K and from that file you would compress your deliverables (via Media Composer or Compressor or equivalent). I will give that a try as well and compare the results.

NorBro said:
...Personally, I am extremely neurotic and would try as many combinations as possible. There are more technical people that can describe what is happening to your pixels or bits or colors, etc. when you are working within various resolutions, but I don't consider it...I just know that my 4K footage does not look right coming from a HD timeline.
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Don't feel bad... Obviously, I'm a bit neurotic too since I've noticed some degradation in detail in this particular project workflow. I have been running through a BUNCH of combinations to see what provides the best end-result. I'm going to have a lot of purging on my hard drive once this "experiment" is over for sure but I think it's important to wring every bit of quality we can out of our gear (cameras, software, etc.) to put out the best possible production... and in a few months something else will come out that we'll have to learn all over again :)

Thank you for the info and help!
 
Donny 123 said:
Does the fs7 with a decent lens need sharpening in camera..? regardless of gamma curve.. if its anything like the f5 is too sharp without anything being added..
Click to expand...

As you see from the previous responses; it's quite a mix bag of personal preference when it comes to sharpening. Honestly, I have never added sharpness to my FS7 footage prior to this and only started considering it due to the scaling issue I have ran into on this project. So for me, the "jury is out" until I sort the scaling.
 
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