Author Topic: Footage feedback  (Read 259 times)

Md. Tauhidul Azam

  • Newbie
  • *
  • Posts: 4
    • View Profile
Footage feedback
« on: September 27, 2021, 06:22:27 AM »
1. can anybody tell me why my footage has that small amount of blinking in the colored area, especially in red?

2. Why did this rolling shutter happen?

Nikon1

  • Hero Member
  • *****
  • Posts: 792
    • View Profile
Re: Footage feedback
« Reply #1 on: September 27, 2021, 06:56:39 AM »
Hi,I can see the Red Flickering in the Fruits Clip, but cant figure out where there would be any Rolling Shutter Effects in this Footage, watched both multiple times, even Frame by Frame, cant see that. Can you point out exactly where that supposed Rolling Shutter Effect should be?
 .
 In regards to the Red Flickering, that might just be normal Digital Noise. Can you provide some Frame from that shot in DNG or a Framegrab from the .mp4 File, cause it seems like the Image was possibly pushed/ boosted quite a bit in editing, which can cause that with this camera. The Very dark Parts of Footage from the 2.1 have always been somewhat noisy, newer Firmware upgrades improved that a lot, but it is still there. (btw. which firmware Version was this shot on? 0.7.0?) So i generally would recommend to not boost the Shadows and Dark Areas of the Footage too far, or else things like this can become very visible in some Lighting Situations.
 Solutions for that would be to just expose a bit brighter, if the Image allows for that without blowing out the Highlights elsewhere in the Frame (in that shot there seems to be room for more Exposure without overexposing anything), or to figure out a way to light that Shot in a way that the overall contrast of the Image is reduced (less Dynamic Range to capture for the Camera, meaning more room to expose Brighter and have less dark areas in the Frame).
 At least that is what i think this is, someone Correct me if i am wrong.

mklinger

  • Jr. Member
  • **
  • Posts: 57
    • View Profile
Re: Footage feedback
« Reply #2 on: September 29, 2021, 09:38:11 AM »
1. can anybody tell me why my footage has that small amount of blinking in the colored area, especially in red?

2. Why did this rolling shutter happen?

Hi, I agree with Nikon1.  What you are seeing, especially with the fruit clip is just digital noise in the red channel probably from boosting the saturation a bit too much and it's getting blown out.  You have to be very careful with these cameras as they don't have the same dynamic range as you'd be used to with normal video cameras or DLSRs.  I would recommend shooting in Cinema DNG for best possible dynamic range and being careful not to blow out any of the colors in post.

FWIW, both the Chronos 1.4 and 2.1 use a global shutter sensor, so "rolling shutter" is not a possible artifact with these cameras. 

Nikon1

  • Hero Member
  • *****
  • Posts: 792
    • View Profile
Re: Footage feedback
« Reply #3 on: September 29, 2021, 09:51:05 AM »
FWIW, both the Chronos 1.4 and 2.1 use a global shutter sensor, so "rolling shutter" is not a possible artifact with these cameras.
Yes. Thats the other thing i was wondering. Apart from the Fact, that i couldnt see anything looking like rolling shutter, its literally not possible to get rolling shutter effects on an Camera like this (unless you seriously abuse it in some elaborate ways to do exactly just that, but talking about normal operation).
 Might look a bit choppy in playback, but that is most likely Editing, if there is any Stuttering in that footage, and its not just my PC or my eyes playing tricks on me.
 Could happen when saving footage as H.264 in 60fps, then putting it into an 24fps Timeline and the Video Editor will possibly skip some Frames in uneven Intervals, making the Playback weird and not really as smooth as could be, if you dont change playback speed to match 24fps (or just save 24fps in-camera already, if that is what you usually use for the final Video).
 Could also be the Lack of motion blur from shooting some really short shutterspeeds, will sometimes also lead to "choppy" Footage with fast movement, if that is What Md. Tauhidul Azam means when he talks about "rolling shutter"?
 Can Provide Examples and elaborate on that topic, if needed, let me know.
 .
 Only things i could think of from off the top of my head right now at least.
« Last Edit: September 29, 2021, 10:01:20 AM by Nikon1 »

Md. Tauhidul Azam

  • Newbie
  • *
  • Posts: 4
    • View Profile
Re: Footage feedback
« Reply #4 on: October 04, 2021, 01:25:27 AM »
Hello Everyone! Thanks a lot.
I have already found out the problems!
It was my saving file format. I saved files at 24fps, Thats why it looks choppy, then I saved the file at 30fps, looks okay to me. But When I save files at 60FPS, it becomes faster! Thats mean shooting at 1000fps and saving at 60 fps, actually will give 500fps slow-motion, right?
Please, Help me to figure out the saving options!
What is bit per pixel (BPP)? What is the standard BPP for chronos2.1HD?
1000FPS, 1920*1080, 180degre, Compressed rate 60MBPS, 12bit depth, what should be the BPP?
This link shows it 0.96!
https://support.intopix.com/compression/
And this link tells 0.289...
Which one is correct?
How to calculate this?
What should be the ideal values for those to get the maximum footage result with this camera?
BPP, Saved file frame rate, Maximum bit rate?
Thanks a lot guys!

Nikon1

  • Hero Member
  • *****
  • Posts: 792
    • View Profile
Re: Footage feedback
« Reply #5 on: October 04, 2021, 07:42:03 AM »
So about the Framerate / Save File Framerate:
 I need to explain this a bit more into detail, will be hard to understand otherwise.
 First, forget anything related to Playback-Speed or how slow your footage looks, and imagine a very fast Sports DLSR taking a lot of single Images. The Chronos is nothing else than just that, but way faster basically. Lets now imagine that camera captures a Resolution of 1000x1000 Pixels and is able to capture 1000 Frames Per Second (fps).
 The Object said camera is capturing, is a very small object, moving at an constant speed, and will move from the Left border of the Frame to the Right border of the Frame in exactly 1 Second, While covering exactly the area of 1 Pixel.
 In that situation, the Camera should capture exactly 1000 frames of the Object in frame over the course of that 1 Second time, and in every frame the Pixel / Object Should advance one Pixel to the Right.
 This still does not tell you anything about how fast it will look when played back, right now it is just 1000 actual single Images Sitting in Memory of the Camera before Saving.
 To help understand Recording framerate, lets now assume, the Same Camera is able to capture 2000 or just 500 Frames Per Second on the Same Settings.
 In the Same Situation as Before, it will now capture 2000 or 500 Single Images of the Object in Frame. for the 2000fps Scenario, we would now have more temporal Detail, meaning every frame will now only advance the object 1/2 Pixel in distance, while for the 500fps Shot we would only get an image on every next Pixel and miss every odd Pixel, which means we miss out on possibly a lot of Information.
 .
 Now, if we in Theory had an monitor able to display 2000 actual Frames Per seconds, and we would play each of the Three Sequences of Single Images back at the Same Rate They where Recorded at, every one of the Clips would still play for exactly 1 Second while showing every recorded Frame in order, or what we call "real time" Playback.
 So Recording Framerate still doesnt tell us the full story about how slow or fast the Final Clip looks.
 If we play back the 1000 Frames from the 1000 fps one at a Rate of 25 Frames in one Second, it would take 40 Seconds to display all of the Recorded Frames.
 If We Play those same 1000 Frames back at a rate of 60 Frames in one Second (60fps), it would only take 16 Seconds to display all of the Recorded Frames in correct order.
 We can obviously also take those 1000 same Frames and Play them Back at lets say 10fps, which would take 100 Seconds to display all Frames.
 10fps however will look VERY Choppy and at that point becomes very noticeable a fast Slideshow of single Images rather than "Smooth" Video.
 .
 Whatever is accepted or perceived as "smooth" Framerate is very Subjective. The general Rule is something like 24~25fps as the Lowest thing the majority of people will perceive as Fluid Motion and at 60 fps and above the absolute vast Majority of People will not be able to tell the Difference how many Frames per Seconds are displayed, unless very Fast moving stuff is shown (mouse Pointer on High Frame-Rate Monitors and such).
 So what framerate to use is to a big part up to Preference and also up to where you want to display it after shooting. Does not make a lot of sense for example, if you shoot highspeed for a Movie which will be Played back at 24 or 30fps in the End Anyways, to Edit your Highspeed-Camera shots in 60fps, you are just wasting Frames/ Slower Playback speed at that point.
 As Explained with the Example above, Playback framerate is what in the End determines the Relative Playback speed compared to Real Time. for example 40 times Slower than Real Time Playback with the 1000fps Recording Framerate and Playback at 25fps. If you now Play the Same Clip back at 50fps, it becomes 20 times Slower than Real Time Playback speed, but the Footage isnt suddenly 500fps or something, it still was Shot at 1000fps. It just plays faster and in theory smoother, if your Monitor and Eyes even notice the Difference.
 .
 A thing to watch out for however, is that if you save for example in 60fps, and your Video Editor is set to 30fps, your video will still play back at 60fps speed and most Editing software will just "throw away" all the Other half of Frames. This is usually done, because you want your audio synchronous to your video, and so priority is not on displaying every frame here, but to preserve the "correct" Playback Speed. Most video Editors will allow you to adjust speed of such clips to play slower, and like in this case show all the Frames (in this Case 0,5x Playback Speed of the File), but you have to know/ remember that and do that every time.
 Thats why i would highly recommend to already set the Correct Framerate in Camera (The Framerate at which your final Edited Videos will be exported/ saved at ) which you later use for Editing, so you dont have to think about it later. For me it is 25fps, because that is what i export about 95%++ of all my Videos at anyways.
 .
 Hope this explained that a little bit, and didnt just cause even more confusion.
 .  .
 Regards Correct Settings, i Set that Bit Per Pixel for h.264 Output to 8.00 because i just assumed that it was bit depth, and i didnt want do deal with editing 10 or 12 bit, when i save in compressed Formats, but now i am not too sure anymore after reading your reply and looking at that link. Really not sure what the Correct setting is for that one, i just put 8.00 which worked well for me until now. Maybe look in the Manual online, if there is something about it (its actually well written and has a lot of good info in it, i am usually, like now, just to lazy to look it up).
 I usually go for 60MBpS if saving h.264, as its just the highest Bitrate you can get compressed, and should deliver the best Image Quality in .mp4 (If you want even Higher Image Quality use DNG Format, but this requires a lot more Editing an knowledge to use and get good results. For Basic Output, h.264/ .mp4 is still Ok).
 .
 Shutter angel obviously depends on a lot of different things, but for the Traditional Cinematic Motion Blur, somewhere around 180 Shutter Angle is usually a good Setting.
 Framerate and Resolution can be set to whatever you want within the Technical Limits of the Camera, but 1000fps@ 1920x1080 is the Maximum Framerate you can get at the Highest Resolution of this camera, so unless you want your final Footage to look even Slower, this is usually also a good Setting.