Latest post Fri, Dec 22 2017 9:21 AM by Pat Horridge. 12 replies.
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  • Mon, Dec 18 2017 11:16 PM

    Color Space

    Hi all

    We want to edit in 4k and are accepting that we need to transcode. We shot Varicam in 4k with VLOG but i havent the foggiest idea what the best project setting is. We want to have enough headroom for grading. We did a rec 2020 project and it forces us to transcode at DNxHR4444 and every terabyte ends up bcomeing like 3tbs. Insane. Is there a project setting (RBG 709? DCI p3? etc etc)  that wont lose any data, provides headroom and uses media efficiently? After we choose the color space, what is the best target video resolution? Thanks!

    HP z840, with dual E5-2634 v4 Xeon processors at 2.2ghz (10 cores each). 32GB ram. NVIDIA m4000 video card. EVO SAN with 96tb and raid 5 over Cat6. Artist... [view my complete system specs]

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  • Tue, Dec 19 2017 2:28 AM In reply to

    • jef
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    Re: Color Space

    Well first, what codec was used?  From the Panasonic website I see the following options:

    AVC-Intra4K444, AVC-Intra4K422, AVC-Intra4K-LT, AVC-Intra2K444, 
    AVC-Intra2K422, AVC-Intra444, AVC-Intra200, AVC-Intra422, 
    AVC-Intra100, ProRes 422 HQ, ProRes 4444

    This will tell you a lot.

    Jef

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  • Tue, Dec 19 2017 9:58 AM In reply to

    • Bruno M
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    Re: Color Space

    Guywithcat:
    After we choose the color space, what is the best target video resolution?

    Don't you have any specs for deliverables?

    If I'm assuming that you'll be looking at a fairly high spec delivery, it would seem best to edit in MC with proxies and go to the original camera files in Resolve or Baselight for the final grade.

     

    HP Z800, HP G3 Studio, SonnetFusion RAID, Mojo DX, Symphony 2018.9, JVC DTV1910 HD tube monitor, HP Dreamcolor, Avid Artist Color, Avid Transport [view my complete system specs]
  • Tue, Dec 19 2017 12:32 PM In reply to

    Re: Color Space

    Lots of confussion over colour spaces nowadays.

    A bigger colour space doesn't have higher value digital information. If you are in 10 bit its still 1024 values whatever colour space you are in.

    The colour space defines how those digital values represent actual visual colours.

    So for the Green value of 512 (in 10bit) in REC 709 will have a certain green look to it

    That same value in P3 will look less green as the P3 colour space is larger

    That same value in REC 2020 will look even less green because 202o is even larger again.

    If you imagine the max green value for 10 bit is 1024 then in each colour space the brightness/saturation of that bit will look different despite the actual value being the same.

    Setting a colour space tell our applications how to handle those values but its not changing the values.

    As others have said it really depends on what you need to deliver.

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  • Tue, Dec 19 2017 7:09 PM In reply to

    Re: Color Space

    Hi all...

    We shot VLOG 10 but 422 AVC intra. It is ungraded. I guess I am asking what a fairly safe space is with enough headroom to grade. I understand some things will look more green or vary in color based on the spaces as Pat has said (thank you) but I have 20 options. For example if i choose rec 709 does that give me room to grade comfortably? And beyond that, when we transcoded in 2020 a TB of footage took up 3tb of space. I would like to keep this as lossless as possible but also not blow out our harddrives. We of course will end up (later!) editing HD but at this stage I need to play with some footage and grading in house for several reasons.

    Thanks!

    HP z840, with dual E5-2634 v4 Xeon processors at 2.2ghz (10 cores each). 32GB ram. NVIDIA m4000 video card. EVO SAN with 96tb and raid 5 over Cat6. Artist... [view my complete system specs]

    I think we need a few more digital HD formats

  • Tue, Dec 19 2017 10:00 PM In reply to

    Re: Color Space

    Can i BUMP this?

    HP z840, with dual E5-2634 v4 Xeon processors at 2.2ghz (10 cores each). 32GB ram. NVIDIA m4000 video card. EVO SAN with 96tb and raid 5 over Cat6. Artist... [view my complete system specs]

    I think we need a few more digital HD formats

  • Tue, Dec 19 2017 11:37 PM In reply to

    • DStone
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    Re: Color Space

    I'd be tempted to edit in DCI P3. It has a wider gamut than Rec. 709, and you don't need the full B.T. 2020 gamut.

    DIY quad core I7-4790K, 32Gb, NVidia RTX 2060 Super 8, Win 10 Pro, MC (generally the latest or the one just before) [view my complete system specs]

    Dave S.

  • Wed, Dec 20 2017 10:26 AM In reply to

    • Bruno M
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    Re: Color Space

    Guywithcat:
    We of course will end up (later!) editing HD but at this stage I need to play with some footage and grading in house for several reasons.

    I think you'll appreciate that it's going to be hard for anyone to give you specific advice if you're just playing with/grading the footage for undisclosed reasons. I've played with setting Avid to 2020 but since I cannot monitor the image correctly there's no way I can really evaluate this workflow in any meaningful way.

    Do you have a monitor that will handle these wide gamuts accurately? If not, then I wonder what you're hoping to achieve with these 'tests'.

    HP Z800, HP G3 Studio, SonnetFusion RAID, Mojo DX, Symphony 2018.9, JVC DTV1910 HD tube monitor, HP Dreamcolor, Avid Artist Color, Avid Transport [view my complete system specs]
  • Wed, Dec 20 2017 7:00 PM In reply to

    Re: Color Space

    HI all

    We are trying rgb 709 and it looks good. But now I have a new question, all of our 4k footage is taking up 3 times as much space as the footage itself once it is transcoded. In a 4k 4096x2160 project, with RGB 709 (and for that matter in rec 2020) it only allows us to transcode to DNxHR 444. So for example if we transcode 512GB it takes up around 1.5 TB or even more. What makes this hard to understand is that it does not offer us any other option of DNxHR in 4k. Any idea why this is? When we used to do HD we could pick numerous sizes. Help?

    HP z840, with dual E5-2634 v4 Xeon processors at 2.2ghz (10 cores each). 32GB ram. NVIDIA m4000 video card. EVO SAN with 96tb and raid 5 over Cat6. Artist... [view my complete system specs]

    I think we need a few more digital HD formats

  • Wed, Dec 20 2017 10:52 PM In reply to

    Re: Color Space

    Because if you want to stay in 444, and therefore choose an RGB709 project, you will only have available Avid MC’s 444 codecs. Same is true when working in HD and RGB709/444. 

    Some cams will shoot heavily compressed 4K, but doing post in 4K at 444 requires a solid postproduction codec.

    For projects like that, an offline-online workflow could likely make sense.

    Media Composer Symphony | PT Ultimate | Win10 HPZ | OSX MBP | ISIS5000 [view my complete system specs]
  • Thu, Dec 21 2017 6:54 PM In reply to

    Re: Color Space

    What is a project closer to 10 bit 422 which comes out of the camera so i can get more like 1:1 use of space for camera originals to transcoded media?

    HP z840, with dual E5-2634 v4 Xeon processors at 2.2ghz (10 cores each). 32GB ram. NVIDIA m4000 video card. EVO SAN with 96tb and raid 5 over Cat6. Artist... [view my complete system specs]

    I think we need a few more digital HD formats

  • Fri, Dec 22 2017 5:55 AM In reply to

    • luca.mg
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    Re: Color Space

    Guywithcat, it really looks like You're beginning the meal from the dessert; edit first instead, and grade later. You can cut using whatever lightweight codec Avid offers, and later rebuild the final cut in high resolution and grade.

    Symphony 20.10, BM Intensity Pro 4k, Windows 10, i7-5930K, 32 GB ram, Quadro K620 [view my complete system specs]

    peace luca

  • Fri, Dec 22 2017 9:21 AM In reply to

    Re: Color Space

    Why convert all your 422 media to 444 and have to work RGB? Makes no sense you gain nothing.

    444 RGB can't be compressed unlike YCbCr which can you can work 444 in YCbCr but as your source is 422 there's little point.

    You have no other resolution options in RGB because you can't compress RGB. I do training course that explain exactly why but sufice to say in RGB the balance of information isn't equal. Green is much larger than Red and thats larger than blue. So any compression will cause an imbalance between the colours. Such that reconstruction of the light for each oixel will be altered causeing colour shifting and artefacts. So RGB as a choice only offers uncompressed. with YCbCr you have matrixed the RGB to make luma (black and white) and colour difference signals. We can then chose to compress the luma differently to the colour difference signals. without risk of colour hue shifting.

    As other posts suggest use an offline online workflow. Youe offline colour space has to match your viewing monitor.

    Rec709 if its a TV display. DCI P3 if you choose to use a projector for offline editing that can actually manage DCI P3 colour space.

    When the offline is done then look at the conform and the requirements for delivery.

    But to be honest its cheaper to dry hire a finishing suite with the correct kit than build it yourself for one job.

    Time you add in a decent grading display(probably a projector) scopes that can handle the colour space you need. Storage etc its no cheap setup. And you have to calibrate it all first.

     

    ACI Moderator. I'm not employed by Avid or work for them. I just do this in my spare time. Normally using the current Media Composer version on My... [view my complete system specs]

     

    Broadcast & Post Production Consultant / Trainer  Avid Certified Instructor VET

     

    QC/QAR Training - Understanding Digital Media - Advanced Files * Compression - Avid Ingest - PSE fixing courses and more

    All bespoke and delivered onsite at yours. Or delivered via hosted Zoom session.

     

    T 07581 201248 | E pat@vet-training.co.uk | W www.vet-training.co.uk |

     

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