Latest post Fri, Jul 25 2014 7:46 AM by Job ter Burg. 4 replies.
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  • Thu, Jul 24 2014 8:28 PM

    • rdmartin
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    Choosing the correct film mask for DCP projection from RED 5k FF

    I shot Red Epic X at 5k FF which does have small black bars on the top and bottom when bringing the footage into avid for editing. I believe it’s a crop factor that is natively burned into the picture because 1.9 full container does not adhere to the aspect ratio of 16x9?? 

    I put on a 1.66 mask onto the film and altered the height to 93. This was the thinnest I could make the mask so that the outskirts of certain shots that were stablized would not resize up and down the screen when played. The hight of 93 is equivalent to the RED crop factor and this mask was also need to be put onto the screen to make shots that were resized (and thus covered the full 16x9 avid editing window) to then be uniform with the unaltered RED footage. In other words - I added a mask and just shrunk it to a height of 93 to match the crop factor of the Red Epic X 5k FF footage. 

    THIS IS THE LOOK I WANT WHICH IS EQUIVALENT TO FULL CONTAINER 1.9:1 ASPECT RATIO AND NOT ALTERED.

    Anyway, I am creating a DCP for cinema output to 2k and/or 4k for film festivals.

    I shot the film NOT wanting a letterbox applied to the film when it is screened for audiences at film festivals. So we framed all the shots to use the whole image available on the Red 5k ff sensor. 

    I am now reading around and finding that projectors at film festivals do not support full container 1.9:1 aspect ratios. They only support 1.85 or 2.39? What About 1.78 or 1.66?

    When color correcting the raw files in Resolve and then relinking all the effects via the online edit - I do not want to mask over my images with a thick 2.39 matte because that not how it was shot and intended to be screened. When I watch a 1080p 1.85:1 film on my television is see it is even a thinner letter box than my film when export at 1080p from avid with the mask equivalent to 1.9:1 aspect ratio. So i figured, that is fine, I will use the 1.85 mask for my 2k or 4k DCP, But then why is it a super thick mask when placing onto my film in avid??? It looks more like a 2.35:1 mask... why does it not match my television? My pojects raster size is 1920x1080.... should I be changing the mask margins setting to 1.9:1 to match my footage or something??? Yet I see no changes when experimenting with apply masks in avid using different mask margin presets.....I notice that my aspect ratio settings under the format tab are greyed out at 16x9.... is this the problem?

     

    So my question are:

    1.) Are 2k and 4k films authored onto the dcp with a 1.85 or 2.39 letterbox matte burned onto the film upon export and then there is no recropping when read by the projector and sent onto the screen in cinemas? What if I actually did author my film onto the dcp as 1.9 full container - would it not be compatible with projectors and simply not play or would the projector automatically recrop/resize the image into a new aspect ratio (thus hitting the screen at 1.85 or 2.39, which then masks over much of the image anyway?

    2.) If placing a matte over the image is required for cinema screenings - which is the thinnest and most applicable matte to put onto the film in Davinci Resolve or Avid so that it will be compatible with dcp projection and cover the least amount of the image which I intend the audience to see?

    3.) Also, I hear many digital cinemas do not yet project 4k - if I were to author my dcp file as 4k regardless, would the projector automatically down convert the film to 2k and keep the aspect ratio of the film correct? Or would the film authored onto the dcp simply not play?

    4.) I do have resizes that I have applied to certain shots.

     

    Please help - I cannot find this information concisely anywhere online.

  • Thu, Jul 24 2014 8:37 PM In reply to

    • Nnata
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    Re: Choosing the correct film mask for DCP projection from RED 5k FF

    Yes I am having this same problem.

  • Thu, Jul 24 2014 9:23 PM In reply to

    Re: Choosing the correct film mask for DCP projection from RED 5k FF

    rdmartin:
    1.9 full container does not adhere to the aspect ratio of 16x9?
    Correct. Red 5K is 5120x2700, meaning an aspect ratio of ~1.896:1, where as HD video is 1920x1080, meaning an aspect ratio of ~1.7778:1.

    rdmartin:
    1.) Are 2k and 4k films authored onto the dcp with a 1.85 or 2.39 letterbox matte burned onto the film upon export

    No. They are encoded and stored as either Flat (1.85:1) or Scope (2.39:1) in either 2K or 4K. So the actual canvas size is 1998×1080 (2K) or 3996×2160 (4K) for 1.85:1, or either 2048×858 (2K) or 4096×1716 (4K) for 2.39:1. Source.

    The projectors have a chip canvas of 2048x1080 (2K) or 4096x2160 (4K) – which is almost 1.9:1. The source is pixel mapped onto that canvas (leaving either part of the top/bottom or the sides unused), and the projector's lens zoom is used to fill the cinema screen – using a preset of either 1.85:1 or 2:39:1. This is done with presets, so the screen masks and the projector's zoom settings are stored for these two formats. Cinemas don't letterbox or pillarbox, they use a constant height, the width of the screen is variable (meaning they use adjustable frame masks to the side, with or without curtains to hide the unused part of the physical screen).

    Technically, Digital Cinema projectors are capable of playing back 1.9:1, but hardly any theaters have a preset to present that format, as 1.85:1 and 2.39:1 are the two standard aspect ratios currently in use for cinema distribution. This is why festivals (and sales agents and distributors) are going to require you stick to either one of those formats. If you insist and create a 1.9:1 DCP, chance are most theatres will automatically do the cropping to 1.85:1 for you – not a great solution.

    You could of course opt to place your 1.9:1 image inside a 2.39 canvas (pillarboxed), but it would mean you can only achieve an active picture of 1636x858 ('2K' DCP) or 3260x1716 ('4K' DCP). Whenever one would want to use an HD 1.78:1 (16:9) aspect ratio, or 1.66:1, they would pillarbox this inside a 1998x1080 (1.85:1) canvas as well. In all these cases, theatres are very unlikely to be able to correctly place the masks to the sides of your actual active image.

    So bottom line, you will have to make a small adjustment, as you should not have framed for full aperture if Digital Cinema is your release format.

    The difference between 1.9:1 and 1.85:1 is not going to be staggering. However, you might run into situations where headroom is less than you would desire. IMHO, the best way to go about this is to keep the top of the 1.9:1 frame the same for the 1.85:1 frame, basically cropping just the bottom. This tends to preserve headroom framing – same technique is used when they frame 2.39 and HD using Common Topline framing that a lot of DoP's like to use.

    rdmartin:
    which is the thinnest and most applicable matte to put onto the film
    Note that the Film Masks in MC are labeled for SD 4x3, so they are completely incorrect in an HD project (so your V=93 mask does not at all crop to 1.66:1 but rather to 1.91:1). However, if you decide to go for 1.85:1 (which I would recommend), you just need to make sure you get a 1.85:1 aspect ratio. That means 1920 pixels (your HD canvas) divided by 1.85 = 1037.84 (desired image height), divided by 1080 (your HD canvas) = ~0.96. So apply a mask and set the V-size to 0.96. Note that MC7 offers a Target Mask feature, for which you can set the aspect ratio in the Format tab of the Project Window.

    rdmartin:
    I hear many digital cinemas do not yet project 4k
    True. And 4K workflows are rather heavy to pull off. And if you are finishing in Media Composer there is no way at this time that you can finish in 4K or 2K, you will always end up in HD (1920x1080). You would need to conform the cut in Resolve or whatever finishing tools you may have available.

    rdmartin:
    if I were to author my dcp file as 4k regardless, would the projector automatically down convert the film to 2k
    As far as I know: yes. This avoids having to send specific packages to specific theatres. HOWEVER: if I were you, I would not risk it, and send a 2K DCP (even if you master in 4K), just to make sure you send the very most common type of DCP currently in use.

    rdmartin:
    4.) I do have resizes that I have applied to certain shots.
    Not sure why that would matter. You will lose some of the original resolution when you resize or stabilize, but none of that is going to matter much. In my experience you can rather easily go up to 150% size and not even notice it. Easier on close-ups than on wide shots.

     

    Also see http://www.red.com/learn/red-101/video-aspect-ratios

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  • Fri, Jul 25 2014 12:24 AM In reply to

    • rdmartin
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    Re: Choosing the correct film mask for DCP projection from RED 5k FF

    To clarify - my finishing will take place all in Davinci Resolve (Reapplying a mask/letterbox, stabolizers, and image resizes to the original Raw footage after it is color corrected) and thus the film will be exported out of Davinci Resolve as well. I am sending my avid project into Resolve as an AAF file.

    I edited the film in Avid and will export a Quicktime reference film out of Avid as a depiction of how the AAF film should look exactly (including it's aspect ratio???) so that they can match all the effects back up to it when they apply them to the AAF sent to Resolve.

     

    Job ter Burg:
    Note that the Film Masks in MC are labeled for SD 4x3, so they are completely incorrect in an HD project (so your V=93 mask does not at all crop to 1.66:1 but rather to 1.91:1). However, if you decide to go for 1.85:1 (which I would recommend), you just need to make sure you get a 1.85:1 aspect ratio. That means 1920 pixels (your HD canvas) divided by 1.85 = 1037.84 (desired image height), divided by 1080 (your HD canvas) = ~0.96. So apply a mask and set the V-size to 0.96. Note that MC7 offers a Target Mask feature, for which you can set the aspect ratio in the Format tab of the Project Window.

     

    I altered the vertical height of the mask to 93 in order for the resized and stabolized shots (which then covered the entire 1.78 16x9 canvas as a result) to mirror the crop factor that is placed onto my transcoded 1.9:1 red footage files and imported onto avid's 1.78 canvas. So there is a thin top/bottom letterbox on the film itself that avid automatically applies.

    So your directions are: duplicate the sequence, alter the 1.66 mask which I had altered the scaling height of 93 (orginally at 80) to 96. Fixed aspect ratio should be unchecked and the V and H positions should stay at 0? 96 represents the aesthetic of an 1.85 aspect ratio being dislayed on a 1.78 canvas???

    So it really doesn't matter which mask you apply in avid because they are all incorrect and don't represent the thickness/thinness of what they should be on an HD canvas? ..... I presume in Resolve that they do?

    Furthermore, in format, change the target mask to 1.85. click "apply" and then "ok"   - Correct?

    Can you explain what exactly this feature does? How does it apply to creating a quicktime reference file or an AAF that exactly represents how the film should be screened from the dcp at 1.85:1???

    Job ter Burg:
    IMHO, the best way to go about this is to keep the top of the 1.9:1 frame the same for the 1.85:1 frame, basically cropping just the bottom. This tends to preserve headroom framing – same technique is used when they frame 2.39 and HD using Common Top framing that a lot of DoP's like to use.

    Checkout the screenshot: notice the different masks (the lowest being the cropped factor of my laptop display itself. The middle being the mask set to 96 and the inner most one being from the masked burned onto the footage as a result of the media being transcoded into avid.

    How should I remove this mask burn in? Does it matter? I'll be relinking to the raw files and if placed into a 1.85 project I presume that this burn is would just simply by thinner as dislayed? But than I should just reapply a makeshift mask agian to have the blown up and resized shot mirror then this mask? I presume not... since the purpose of creating a dcp file is to have it be exported without an artifical or aesthic mask??? Does this mean I will have to resize (blow up) all my shots?

     

     

    So then to be clear, you can only ever work off of  as well as export out a 16x9 1.78:1 canvas movie from Avid? The purpose of placing a mask over that canvas movie is to represent on your quicktime reference file what to replicate in Resolve when creating the poject settings, conforming the AAF and then exporting? So in resolve you can setup a project raster that is 1.85:1 and seamlessly export a file in those dimensions as well? So therefore the cinema projectors do not need to zoom or reframe at all  - the film on your dcp will completely match thier presets???

     

     

    Job ter Burg:
    HOWEVER: if I were you, I would not risk it, and send a 2K DCP (even if you master in 4K), just to make sure you send the very most common type of DCP currently in use.

    What is the difference between mastering and authoring to dcp? Are you saying I should export out a mastered 4k file from Resolve and have that file be downconverted to a 2k file which will be authored onto the dcp? Or should I export out seperate 2k and 4k files from Resolve and just author the 2k file onto the dcp. Is there no difference?

     

     

  • Fri, Jul 25 2014 7:46 AM In reply to

    Re: Choosing the correct film mask for DCP projection from RED 5k FF

    rdmartin:

    I edited the film in Avid and will export a Quicktime reference film out of Avid as a depiction of how the AAF film should look exactly (including it's aspect ratio???) so that they can match all the effects back up to it when they apply them to the AAF sent to Resolve.

    Sounds good. Resizings and repositions will come across via the AAF as well.

    So your directions are: duplicate the sequence, alter the 1.66 mask which I had altered the scaling height of 93 (orginally at 80) to 96. Fixed aspect ratio should be unchecked and the V and H positions should stay at 0? 96 represents the aesthetic of an 1.85 aspect ratio being dislayed on a 1.78 canvas???

    I would create two additional video tracks in your timeline.

    On that top layer, place a 0.96 mask (just use any of the masks and set it to V size = 96, positions all at 0). This will show you the ~1.85:1 aspect ratio (tiny bars at the top and bottom). Your source footage will still show a bit of extra letterboxing at the top and bottom now, though, because the black bars are bigger. So...

    ...on the layer just below the top layer, place a Resize effect, set the scaling to 103% (fixed ascpect ratio ON), all other positions set to default. (when I was discussing Common Topline, I was wrong, you will be cropping sides, not top/bottom, so it does not apply). This should get rid of the black bars that are already on your image, and also chop away a bit of the image left and right. Why the 3% blow-up? Because the active picture of your source files is 1012.49 pixels [1920/(5120/2700], and the height of the active 1.85 canvas would be 1920/1.85=1037.84. 1037.84/1012.49=1.025.

    Make sure to monitor the top video track.

    Any footage you place under these two effects will now be affected by these two effects. If you apply a resize/blowup, reposition or stabilize to any of these shots, make sure that no frame edges are visible inside the 1.85:1 canvas (or else blow up the shots to get rid of these edges).

    When you conform in Resolve you igore or remove these two effects tracks, as they are just for in-Avid monitoring purposes.

    If you already cut the movie, you might want to skip all this and do the reframing in Resolve. 3% difference is very little and should normally not ruin any composition.

    So it really doesn't matter which mask you apply in avid because they are all incorrect and don't represent the thickness/thinness of what they should be on an HD canvas? ..... I presume in Resolve that they do?

    In Resolve you would set up the project at a native 1.85:1 canvas size. No need to mask there.

    Furthermore, in format, change the target mask to 1.85. click "apply" and then "ok"   - Correct?

    You can use Target Mask in stead of the top mask I just described. After setting it to 1.85 and clicking Apply, you go to the record monitor, right-click, and choose Set Target Mask and set it to either Grey or Black. This will now show you a 1.85 Mask. You can apply the same Target Mask in the source monitor (right click in that monitor). However, these masks only appear in the Source/Record windows, NOT on your client monitor or in Full Screen Mode. Unless you have Mojo DX or Nitris DX, in which case you can also apply the Target Mask in Video Output Settings. BUT: this Target Mask is ignored during export (and in the AAF), so you would need to add the .96 mask for export anyway.

    So then to be clear, you can only ever work off of  as well as export out a 16x9 1.78:1 canvas movie from Avid?
    Yes. Avid is a video machine and only has SD and HD canvas sizes. You can just Export to QT with the Same As Source option selected and the export will be a 1920x1080 movie with the black letterboxing you added.

    So in resolve you can setup a project raster that is 1.85:1 and seamlessly export a file in those dimensions as well?
    I'm no Resolve expert but yes, in Resolve you would work on a 1.85 canvas, and export as 1998x1080 or 3996x2160 (1.85:1).

    When you subsequently create a DCP, you create it as either 1.85:1 2K or as 1.85:1 4K, and the resulting DCP will be flagged as being 1.85. The playback server in the cinema will send that flag to the projector, and the projector and the screen masks will then be set to 1.85:1 and your image will fill the 1.85:1 cinema screen.

     

    What is the difference between mastering and authoring to dcp?

    A master is a master, the final result of your production, like your conformed negative. A DCP is a deliverable, like a film print. A DCP is not a master, but a 'release print'.

    Usually, after finishing, you end up with a stack of sequential .DPX files plus a a bunch of sound files (5.1 full mix, M&E, stems). From that you can create various deliverables. You may also create a video master in Rec709 color space and in 1920x1080, so you can make screening copies.

    You can probably do a DCP export straight from Resolve, and that's OK, but you should not consider that to be your master.

    For professional digital cinema releases they will mostly create a DCDM (digital cinema delivery master), which contains all available audio tracks (including various language versions) plus a stack of sequential .j2k files (JPEG2000 encoded version of your .DPX master), plus any subtitling files available. Distributors get these DCDM's, then make a DCP from that. They can add their own ident, choose whatever the approproate language is for sound and subtitles.

    Are you saying I should export out a mastered 4k file from Resolve and have that file be downconverted to a 2k file which will be authored onto the dcp? Or should I export out seperate 2k and 4k files from Resolve and just author the 2k file onto the dcp. Is there no difference?

    Honestly, I would not know which would be better, but I would assume it would be best to finish in 4K, export a 4K master, then rescale in resolve to 2K and export that as a 2K master. Most likely any DCP encoder can handle the conversion from 4K to 2K, but they will likely use different scaling techniques, not sure which would be better, but my money would be on Resolve do the better quality scaling.

    The whole 4K post is going to take heaps of processing power and storage, four times as much as 2K, while you could argue that there is very little effective advantage – don't take my word for it but read what Panavision's John Galt said about the matter: "if you had true 4K resolution in your local theater, everybody would have to sitting in the first 6 rows. Otherwise they wouldn't see any extra detail. Their eyes wouldn't LET them see it." At the same time, 4K is coming, whether we need it or not, and OTT services like Netflix do allow you to supply 4K, so in that light you may want to future-proof your production for 4K delivery.

     

    Finally, please don't take this the wrong way, but I would urge you to find someone with experience with creating and managing masters and deliverables. It can get complicated rather quickly (we haven't been discussing color spaces yet), and you may find yourself knee-deep in the mud if you take an ad hoc approach.

    Media Composer Symphony | PT Ultimate | Win10 HPZ | OSX MBP | ISIS5000 [view my complete system specs]
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