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8bit color nonsense
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  • The white curve represents a flatter profile in 8 bit where 2% is the limit compared with the red profile.

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  • @tida, it is almost what you said. But precision here is the percent change in Brightness per digital step.

    In my first message here I was talking about : 1/L(profile, Point). I dint take any gamma function saying Luminance was given in a linear mode,hmmm :-)

    For instance take the profile :Gamma2.2 in 8 bits : choose brightness of 2%. Lets calculate x on a scale of 256 that gives that brightness of 2%:

    (x/256)^2.2 =0.02 => x=256*(0.02)^(1/2.2)=43

    What is the difference (delta) of Luminance between 43/256 and 44/256 (1 digital step)?

    delta=(44/256)^2.2 -(43/256)^2.2

    and percent change is: delta/(43/256)^2.2= (44/43)^2.2 – 1=0.052=5%

    You can read it in the graph given by VK : 2% brightness gives 5% in the red 8 bit curve.

  • @hay I have the advantage of being on a mac, so I never bother setting REC709. There's no need. By calibrating my iMac monitor using the built in calibration tools from Apple - my color is almost dead on. And I hear the new cinema displays are even closer. Not many can afford the new Dolby reference monitors. (Dolby absorbed DVS a ways back.)

    As far as calibrating AE if you're on a Windows machine go to the monitoring section of this page.

    And to answer your next question, no it's never been an issue. What I see is what I get. I've never output something with this system and not achieved accurate color.

    You don't transcode to 444. Just ingest Prores 422. but when working in AE work in 32bit, and export 444. It's very simple.

  • Isn't the discussion about simple mathematical problem of loosing information either if you round up/round off or using absolute values and you are allowed to do that in a certain digit region.

    For example you want to multiply and come back to same value by division. It's only allowed to calculate with one digit precision.

    round (value,digits)

    round(0.4 * 0.4, 1) = 0.2

    round(0.2/0.4, 1) = 0.5 (not 0.4 any more)


    Abs (1.5*1.5, 1) = 2.2

    Abs(2.2/1.5, 1) = 1.4 (not 1.5 any more)

    If you do not want to loose information you have to calculate with 2 digits precision but only display one digit.

  • Yes Vitaliy, interesting.

    That is what i was explaining in my last message: granularity comparing 2 profiles (in 8 bits): a flat one and a non flat one. You see in the graph (profile gamma2.2) at 0.1% brightness for 8 bit, granularity is 20. For another profile, a flat one granularity should be less at 0.1% brightness but more at 100% brightness (ie more than 1) but it is not so important since at 100% granularity is less huge.

  • EDIT: scratch this question, compressor cant do mts.

    "when transcoding mts to 444 with compressor, do you see any benefit to using a different file format than .mov? like "image sequence", ddp, h.264 for blu-ray or apple devices, etc?"

  • @ shian

    forgot to add: do you ever use adobe link for moving between AE and premier pro? or do you always use xml/aaf/edl?

  • @ shian

    how do you know in AE if you are in a rec709 444 prores workspace? i know how to work in 32bit float, but since i usually work directly with the mts files (which i assume are 4:2:0), im unfamiliar with checking/confirming AE settings following a 709 444 transcode via 5dtorgb.

    also, on 5dtorgb, have you ever selected "interlaced" for chroma mode? since gh2 footage is interlaced, wouldnt that be better than default for preserving fidelity of the hack? im happy to be wrong here!


  • I haven't ever used Media Encoder. It appears to be Adobe's answer to Compressor which I love for encoding M2v's. Compressor is the only option I know of right now that has given me consistent results in the arean of flawless playback on any player.

  • @Shian, I'm laughing my butt off and thanking you at the same time. "I just shot it side-by-side with 5D Mark II and Mark III cameras, as the C Cam, and the Canon guys all snickered at me.... I just shake my head at this point. The indie world has it's head all the way up Canon's ass. In the end; I was the only one laughing." Thank you for making those elitist morons look like what they truly are. I love it when those situations arise and you are meant to be the joke with the GH2 and you blow their minds with what this little camera could do. Everytime I come to shoot a live concert event and I work with THEM(Canon DSLR owners) they see me with my 3 GH2s they ALWAYS look at me like I'm from Mars. Then I give them the ProRes4444 Master and they don't say a word. I just see their eyes widen.

  • never export twice - use XML/AAF/EDL to transfer your edit into another program. It's lossless. You are simply moving your EDL (Edit Decision List) with the same raw footage you were editing in your NLE into your grading program. All your raw footage comes in and is "magically" edited the way you did in FCP (Premiere, Vegas, or whatever you are using.) If that doesn't explain it, I don't know what will.

    If you export 4:2:2 8bit you will get banding. Use a 444 codec - ProRes or DNxHD

    For vimeo I use Mp4, 2 pass, 18,000 kb/s

    For compressor going to Bluray use a CBR somewhere between 14,000 - 18,000. you'll have to do some tests to see which gives less errors during playback. I have settled on 14,000 myself. but I wish I had @driftwood's knowledge of I B and P frames so I could tweak that aspect as well.

  • So i should import/conform -> proress 422 HQ Then export a sequence for grading to proress 444 then grade tadalalal and export to 444 again?

    How is it that you get 'better' results? I don't get it the output is 4:2:0 and you put it in 4:4:4. and it comes out better?

    The problem we always have that if we export to 422/HQ then import to davinci, and export out after grade that we get some banding, which was not there in the first place.

    This solves it?

  • For those working in AE or on pc in general (and unable to encode prores), there's an excellent codec for uncompressed file. It's called "lagarith lossless codec" and it's the most efficient codec I used (but you'll end up with HUGE files). This codec is for .avi format. First time I used it was for a job for a famous luxury swiss watch maker, and none of the codec or uncompressed format could do the work any justice in its fine details while displayed on bluray. Then I used Lagarith and now I use it for every important project.

  • @shian thanks for your reply! I was sceptical if too detailed wide shots could be too much for the 444cbrandin matrix in all-I-mode, but i will give it another go now, sounds very encouraging your experience!

  • My 2 cents here :-)

    Actuallty what is a color profile for our loved GHx? It is here a signal mapping from 16 bits (direct from sensor) to a signal of 8 bits (recorded).

    Imagine first setting named: F (flat) and a different one: NSF (not so flat).

    Imagine same image recorded in F and NSF. In this image you will get one physical point named E here (of the source signal) having same value in F and NSF. Lets say for instance value of E= 43. The value of E (here 43) reffers to same source luminance in the actual image.

    0 means full black 256 means full white.

    Profile F is flatter than NSF that means that you give in profile F more bits of information for any points whose value < E compared to same points in profile NSF.

    Considering a point P(x,y) of the initial image, lets say : L(F,P(x,y)) the luminance of P(x,y) in profile F, L(NSF,P(x,y)) the luminance of P(x,y) in profile NSF.

    So we have : L(F,E)=L(NSF,E)=43.

    We have 2 cases:

    cases 1: For every P / L(F,P)< L(F,E) we have : L(F,P)>L(NSF,P) so that 1/L(F,P) < 1/L(NSF,P) That means for shadows, profile F is better in term of precision : 1/L(F,P) is the relative precision of signal (while mapping or for any work in PP) in profile F for the point P.

    cases 2: For every P / L(F,P)>L(F,E) we have : L(F,P)<L(NSF,P) so that 1/L(F,P) > 1/L(NSF,P). Here we are in highlights and profile F is worse (less precise) than profile NSF. If we were in a 10 bits signal, precision should be 4 times better (smaller) and it will be ok in term of quality. I think this is the point stressed by @FilmingArt.

    But, yes there is a but, here in case2 L(F,P)>L(F,E) that means we have in highlights a lot of bits of information and precision 1/L(F,P) is quite small (that means quite good) even if greater than 1/L(NSF,P) so that argumentation of @FilmingArt is not so relevant as far as my analysis is ok.

    Again my 2 cents here :-)

  • May I ask respectfully for your optimized Compressor settings?

    BTW, I second having a master in ProRes 4444 to store. You never know which new distribution format will be around when a client is coming back and wants a new version. I tend to offer them very reasonable prices for keeping a master, and they tend to come back eventually. Sometimes even those come back with a desperate look on their faces who didn't want to pay me for keeping a master. Normally I have one deep in the attic ;-)

    Such jobs are the best profit per hour, much better than initial production …

  • @shian I'm just getting in to the grading and post universe and reading your posts and threads makes my head explode on a daily basis but I love it! I feel like every time I read a long discussion about an area I want to stop you and say,"Ok, I heard you tell me to turn the computer on, then you lost me. Can you start from there." LMAO! Thanks for all you dedication and hard work sir.

  • @Shian what about using Adobe media encoder VS AE? Any difference in quality? What is your recommended render settings for sending a 1080p file to vimeo?

  • @Peter123456 you want the cleanest image possible before going to bluray. I've done encodes from both 444 and 422 masters exported from AE with the same settings just to see, and the 444 held up better every time. But I encode in compressor. I've tried letting AE do the compression - no good. I've tried letting toast do it - no good. I spent a week tweaking my settings, and I get the best results from 444 ProRes to Bluray. Even when letting a pro house do the encoding. They love me for walking in with a hard rive and all my assets lined up, and a ProRes444 master.

    Sam's point is valid too. Just make sure if you are going to broadcast that you conform everything back to broadcast standards at the end, or it'll get rejected. But this is broadcast video 101, you guys already know this stuff, right? Cuz you've been dubbing digibeta masters from day one.

  • @balazer Actually 16bit is enough to stop banding, but in After Effects going to 32bpc enables super-white and super-black (i.e. greater than 255 and less than 0). This means one effect could push your colours past the brightest displayable white and then next effect could pull them back into the visible range. In 16 bit this would clip, but 32 bit doesn't.

  • @shian, If my only distribution method is bluray (and I will not make any further changes to the footage in the future), do you still recommend rendering to a 444 high bitrate codec before burning to bluray (as indicated in steps 10/11 of your workflow)? The Bluray max bitrate is 54Mbps, so can't I just render to MPEG 2 around 54Mbps? Thanks for your time.

  • Ok. So my smooth all -2 with Boom is considered flat?

  • benefit? control and flexibility in post