HDRx optimization

[Christoffer Glans]

I'm trying to figure out the best possible way to get HDRx footage to look good, reducing the sharp edges on the X-track. How would you work with heavy HDRx to reduce the artifacts created by the method?
I'm looking into using pixel blur to smooth out the edges of the X-track, but maybe there's more we could work out to get it nicer looking?

 

[Elsie N]

Someone in another thread suggested using DEB in REDcine to dampen minor aliasing on footage. Just wondering if you can apply DEB to HDRx single tracks?

Haven't used HDRx yet so no experience with it. I've shot some footage just a few days ago but haven't offloaded it yet.

 

[Michael Tiemann]

I'm trying to figure out the best possible way to get HDRx footage to look good, reducing the sharp edges on the X-track. How would you work with heavy HDRx to reduce the artifacts created by the method?
I'm looking into using pixel blur to smooth out the edges of the X-track, but maybe there's more we could work out to get it nicer looking?

Well, you already found the method I was going to suggest. Is there something about the footage that makes that not work very well?

 

[Christoffer Glans]

Well, you already found the method I was going to suggest. Is there something about the footage that makes that not work very well?

Well, there's easily some artifacts that happen with pixel motion blur when it won't find the exact pixels to map between, then there's the issue that because it's a "frame in between frames" there will always be a ghost. in movements.

 

[Marc Wielage]

I think you're better off not using HDRx and just shooting conventionally. To me, there's enough dynamic range in the camera right now to handle damn nearly anything. The additional trouble caused by HDRx is not worth the time and expense, at least in my experience. I think it's a great theoretical concept, but in actual execution, there's a lot of issues with it. Just protect the highlights and fill more, and it will work about 98% of the time.

 

[Filip Orlandic]

Use SGO Mamba or Mistika.

 

[Christoffer Glans]

I think you're better off not using HDRx and just shooting conventionally. To me, there's enough dynamic range in the camera right now to handle damn nearly anything. The additional trouble caused by HDRx is not worth the time and expense, at least in my experience. I think it's a great theoretical concept, but in actual execution, there's a lot of issues with it. Just protect the highlights and fill more, and it will work about 98% of the time.

Of course, but then you have those occations where you film an interior and want to see the exterior without it being blown out. There's a lot of potential in HDRx but you of course have to plan for it both for the location and post. If you plan your shoot you don't have to get headaches because of it.

This is why I want to look at how to improve it in order to be able to get these kinds of images. When you are inside a room and look out, your eyes have a dynamic range that can handle both the interior and exterior at the same time. Using HDRx let's you come close to this vision and that is a kind of look that is unique. Better Call Saul has that look in many of the office scenes and it looks very different than other stuff.

Use SGO Mamba or Mistika.

What do they do for HDRx improvements?

 

[Michael Tiemann]

Of course, but then you have those occations where you film an interior and want to see the exterior without it being blown out. There's a lot of potential in HDRx but you of course have to plan for it both for the location and post. If you plan your shoot you don't have to get headaches because of it.

This is why I want to look at how to improve it in order to be able to get these kinds of images. When you are inside a room and look out, your eyes have a dynamic range that can handle both the interior and exterior at the same time. Using HDRx let's you come close to this vision and that is a kind of look that is unique. Better Call Saul has that look in many of the office scenes and it looks very different than other stuff.

That gets to the heart of the "what's the special problem you are trying to fix?" I would aver that if you power-window your window you can use the HDRx info and it can have its own world of motion blur and not look too jarring. To me, the problems come when you really need to blend to things, which is totally different than compositing two things. HDRx gives you a crack at compositing the light and dark in your scene, not blending. Does that make sense? Is it correct?

 

[Filip Orlandic]

What do they do for HDRx improvements?

They use complex optical flow to add motion blur to X frame.

 

[Christoffer Glans]

That gets to the heart of the "what's the special problem you are trying to fix?" I would aver that if you power-window your window you can use the HDRx info and it can have its own world of motion blur and not look too jarring. To me, the problems come when you really need to blend to things, which is totally different than compositing two things. HDRx gives you a crack at compositing the light and dark in your scene, not blending. Does that make sense? Is it correct?

That only works with a few kind of shots. What if someone is sitting in front of the window? Who will pay for animating a power curve around that person frame by frame?.

They use complex optical flow to add motion blur to X frame.

I still don't have the full version of Resolve, but it has optical flow motion blur as well, shouldn't that also be able to do it? I can divide a HDRx R3D source point into the different tracks so a motion blur on the first node of the X-Track should work.

How about frame averaging? Has anyone tested out that with HDRx? (If it works). You would probably need more light, but if you shoot a higher framerate for HDRx, wouldn't the X and A-track come closer to eachother and blend better when converting down to the real framerate? Like, shooting HDRx at 50fps and then after blending and motion blur convert it down to 25fps.

 

[Marc Wielage]

Of course, but then you have those occations where you film an interior and want to see the exterior without it being blown out.

I do it every single day in color correction. It's not that hard provided they didn't let the highlights clip in the histograms and they filled the blacks correctly. Don't forget, we did this for many decades with film. It just takes care and experience.

I'm generally reluctant to let windows blow out and will try to coax detail back into them, for the simple reason that real life rarely looks that way, and I don't like them looking "radioactive" because it draws attention away from the actors. I like to see a little detail in the curtain fabric and in the window frame. But if the DP specifically wants to let the exterior blowout, then we'll have the flexibility to do that.

As one example, Lost was a film show where DP John Bartley had high contrast scenes totally under control. He always amazed me by how well he could control a pitch-black night scene lit (to the eye anyway) by a bonfire, and we were able to retain all the detail of the flames without burning out and clipping... but you could still see the actors' faces in the mids and lows. That was a phenomenal look, and he impressed me week after week with how well he could do that. No HDRx needed. I'm convinced a Red or Alexa or F55 could capture the same thing just fine today, provided you lit it as well as Bartley did.

 

[Christoffer Glans]

I do it every single day in color correction. It's not that hard provided they didn't let the highlights clip in the histograms and they filled the blacks correctly. Don't forget, we did this for many decades with film. It just takes care and experience.

I'm generally reluctant to let windows blow out and will try to coax detail back into them, for the simple reason that real life rarely looks that way, and I don't like them looking "radioactive" because it draws attention away from the actors. I like to see a little detail in the curtain fabric and in the window frame. But if the DP specifically wants to let the exterior blowout, then we'll have the flexibility to do that.

As one example, Lost was a film show where DP John Bartley had high contrast scenes totally under control. He always amazed me by how well he could control a pitch-black night scene lit (to the eye anyway) by a bonfire, and we were able to retain all the detail of the flames without burning out and clipping... but you could still see the actors' faces in the mids and lows. That was a phenomenal look, and he impressed me week after week with how well he could do that. No HDRx needed. I'm convinced a Red or Alexa or F55 could capture the same thing just fine today, provided you lit it as well as Bartley did.

But that's also a combination of shooting and grading. If you, without HDRx shoot interior scenes with windows that will not be blown out, you need to light the interior in order to match the brightness outside. Sometimes that's not possible, either because you shoot very wide angle and don't have room for lights or you didn't have the time to do such lighting. Thing is that if you are doing a scene like that and use handheld and there are people in front of the window then yes, you could animate those windows throughout the scene. But it takes time and money to do that, it also might not work if there wasn't enough lights indoor. HDRx essentially "tracks" that area for you and creates a smooth transition that makes it look more real. Reducing the artifacts is however needed in order to make it look good. 14+ Stops isn't enough for all kinds of shots. If we get a new sensor with 25 stops that might of course be it, but for the time being, getting HDRx to look nice can be both crucial and a powerful tool.

 

[Dermot Shane]

That only works with a few kind of shots. What if someone is sitting in front of the window? Who will pay for animating a power curve around that person frame by frame?.




I still don't have the full version of Resolve, but it has optical flow motion blur as well, shouldn't that also be able to do it? I can divide a HDRx R3D source point into the different tracks so a motion blur on the first node of the X-Track should work.

comparing Mamba's optical flow to Resolve's is much like comapring a 5D to a Dragon.. they are both camera's, but one is vastly better in every conciveable way....

i own both licenced Resolve and Mamba, as much as i don't lurve round trips - if it's needed, it's really needed and that is why i have Mamba standing by

As to who pays to sort HDRx gone wrong? The producer pays... like Marc mentioned, it's very likey to go wrong in at least one shot in a scene... recently for the very first time i had a HDRx scene that went perfectly, text book on how and why to use it... a very smart and experienced DP at the wheel who got the blocking he needed from the director, but that's literaly the one and only time i have not had to sort issues with comps and round trips or throw iall the HDRx out on budgetary grounds...

HDRx optimazation? get the blocking to work with the tools at hand, no low light (actors movements) crossing highlight (windows) at anytime in the scene is a good start

 

[Elsie N]

comparing Mamba's optical flow to Resolve's is much like comapring a 5D to a Dragon.. they are both camera's, but one is vastly better in every conciveable way....

i own both licenced Resolve and Mamba, as much as i don't lurve round trips - if it's needed, it's really needed and that is why i have Mamba standing by

As to who pays to sort HDRx gone wrong? The producer pays... like Marc mentioned, it's very likey to go wrong in at least one shot in a scene... recently for the very first time i had a HDRx scene that went perfectly, text book on how and why to use it... a very smart and experienced DP at the wheel who got the blocking he needed from the director, but that's literaly the one and only time i have not had to sort issues with comps and round trips or throw iall the HDRx out on budgetary grounds...

HDRx optimazation? get the blocking to work with the tools at hand, no low light (actors movements) crossing highlight (windows) at anytime in the scene is a good start

Thanks for that insight.

 

[Christoffer Glans]

HDRx optimazation? get the blocking to work with the tools at hand, no low light (actors movements) crossing highlight (windows) at anytime in the scene is a good start

That's not a very good tip on directing. You block according to the story not post production. If you want the actor to move around and in front of a large window, there you go, you might want HDRx or pay a lot of money for someone to rotoscope the actor out.

The thing is that this kind of thinking is limiting the possibilities of the technologies we have. If we now have a tool to give us usable highlights and shadows in almost impossible situations, why just keep doing things the old ways? That conservative way of using the tools at hand is one of the reasons why Alexa does so well with the old time cinematographers, because they don't have to learn anything new, just keep shooting the same way as always. Thing is, there are a few filmmakers who innovate and see possibilities where others see problems. Kubrick was and Fincher is that kind of a filmmaker. If Kubrick was alive today he would probably have choosen Red, why? Because those two are about control over their shots. Those two are people I look up to for inspiration. "Oh we want to shoot this movie with only practicals using candle lights and daylight? Well we just invent that possibility".

If I see a means to use a technology to get a certain shot that might be impossible for the budget I have I'm inventing a way, simple as that. Last work I did we didn't have the money to rent a dolly or jib, so I just shot it at 90 degrees, 24mm wide at 6K, then 3D tracked stabilized the shots to get something that looks like jib and dolly movements and it works, it looks exactly like it was shot with those tools because I know what I'm doing, because I figured out how. In that way we saved in on those rental costs and could hire extra help on set, which was more important.

I've actually found a way to improve greatly on the quality of HDRx, but I put it in this thread instead because it was more about the way you shoot it rather than post production. But in essence, shoot at a timebase of 50 or 48 fps, apply the HDRx conform (either simple or motion) put it on a 25 or 24 fps timeline and add pixel motion blur at 180 degrees or add 360 degrees on the 50/48 fps material first in order for the vector quality to be better, then render it out with the timeline fps. Then you get smaller distances between each HDRx track and therefore reducing the ghosting. You need quite a lot of movement in order for the pixel post blur to break apart, but the level of artifacts are greatly lower than with regular HDRx.

Here's that thread
http://www.reduser.net/forum/showthread.php?144627-HDRx-Tip

 

[Marc Wielage]

I've actually found a way to improve greatly on the quality of HDRx, but I put it in this thread instead because it was more about the way you shoot it rather than post production. But in essence, shoot at a timebase of 50 or 48 fps, apply the HDRx conform (either simple or motion) put it on a 25 or 24 fps timeline and add pixel motion blur at 180 degrees or add 360 degrees on the 50/48 fps material first in order for the vector quality to be better, then render it out with the timeline fps. Then you get smaller distances between each HDRx track and therefore reducing the ghosting.

This is still not a replacement for simply shooting it and lighting it well in the first place. Do that, and you won't have to take 1 extra second in post having to use HDRx. Trust me, the range is there with both Alexa and with current Red cameras to do this. It just takes work and experience. Technology is not a replacement for skill.

 

[Christoffer Glans]

This is still not a replacement for simply shooting it and lighting it well in the first place. Do that, and you won't have to take 1 extra second in post having to use HDRx. Trust me, the range is there with both Alexa and with current Red cameras to do this. It just takes work and experience. Technology is not a replacement for skill.

I didn't say it's a replacement, just that new technologies shouldn't be overlooked. It does give you very powerful possibilites and all the experience in the world won't help you if you need to do a quick shoot of something and you don't have all the gear needed for matching up the exposure on location. I'm actually a bit surprised about this kind of response. Here's a tip on improving HDRx and the response is "it's not a replacement for skill", well, there's also skill in knowing how to utilize the tech you have.

I would also like to ask if the manpower and time it takes to do a light setup on location to be able to get exteriors and interiors exposed within range is more economical or time saving than just shooting it with HDRx? If the result is as good as the result I'm now able to achieve, I can definitely see how this would save time and money. The extra time in post production is marginal and you wouldn't shoot an entire movie with HDRx, just the shots that needs it. Just the fact that it almost doubles the data is fact alone that it's not viable to be done on every shot.

Then there's the look of having just one light source. If you have a room with the sun as the main light source, shooting a very wide shot of a person in that room and you want everything in range, with the outside of the window visible, but at the same time the actual look of the bouncing light in the room, you are out of options, especially if the room is too small for light rigs or you want to show everything, both ceiling and floor. That kind of look is only possible with more DR and if you don't want to track in a fake background and want it real then you have the technology to do it.

Saying that technology isn't a replacement for skill is true, but this has nothing to do with that, it's about adding another tool to your skill set. Failure to realize the potential of such a tool is worse.

 

[Marc Wielage]

Saying that technology isn't a replacement for skill is true, but this has nothing to do with that, it's about adding another tool to your skill set. Failure to realize the potential of such a tool is worse.

All I can say is I've worked on four or five projects that tried to employ HDRx, and the results were mixed at best. In at least half the cases, we were forced to jettison the additional exposure because of motion artifacts. It's often much wiser to go with a simpler, cleaner post workflow -- partly to save time and money, but partly to get a more organic image in the end.

Trying to justify the use of technology for bad lighting, or (understandably) for limited experience or a severe lack of budget, is the biggest folly here. Trust me: just light it right the first time, and you won't have to use HDRx. Take more time and money on the set and fill more.

 

[joshua csehak]

I've been messing around with this. It's frustrating to see all the shadows exposed well in the A Frame and the highlights exposed well in the X Frame and then blend them together and it doesn't look much different from exposing in the middle. So I took each stream into After Effects, duplicated the A Frame, turned the top layer into a luma matte for the bottom layer, and set it to "lighten", so only the darkest areas of the overexposed A Frame would affect the underexposed X Frame. It came out looking pretty flat indeed. So then I brought it into Premiere and graded it (in Lumetri just maxed the contrast and tweaked the curves to deepen the shadows), and it does in fact look a little better than if I take just the X Frame and grade it (starting with RedLogFilm). Better enough that it's worth the effort? Probably not. But this technique might be useful in other cases.

 

[joshua csehak]

Here the graded version of the AE technique compared to just taking the X Frame and grading it starting from RedLogFilm