The Projector Aspect Ratio indicates the pixel array size at which the projector should be set. It does not necessarily indicate the aspect ratio of the image — or theatre masking instructions — since often times content such as trailers may be letterboxed or pillar-boxed.

Digital Cinema projectors are designed to project Flat or Scope images. Occasionally product is packaged with Aspect Ratios other than 1.85 (Flat) or 2.39 (Scope). For example, an older 1.33 Aspect Ratio film may be packaged as a 1.85 Flat package with black pillars on the sides to “pad out” the 1.33 image to 1.85. (The top and bottom of the 1.33 image would be in the same place as the top and bottom of 1.85.) Similarly, older wide formats such as 266:1 might be packaged inside a Flat or Scope container with horizontal black bars on the top and bottom to “pad” the image up to the top and bottom of 1.85 or 2.39. (The 2.66 would be “common sides” with the 2.39 or 1.85.) In order to alert theatres that these are intentional black bars or pillars around the edges, the Aspect Ratio Field can be modified to clarify what the theatre is getting.

For example, F-133 would indicate a Flat package with a pillar-boxed 1.33 image inside it. S-266 would indicate a Scope package with a letterboxed 2.66 image letterboxed within the 2.39 etc. The theatre would have the option of adjusting its masking to block the black pillars.

NOTE: Never use this labeling device with Trailers!

Trailers are almost always produced in both Flat and Scope versions regardless of the aspect ratio of the feature advertised. Quite often, the “non-native” format of the trailer is letterboxed or pillar-boxed. These “cross aspect ratio” trailers should never be identified using this method (F-239 or S-185) since theatres should not be encouraged to change masking for a single trailer on the playlist or this could inadvertently spoil the needed masking for the feature. (Changing masking from trailer to trailer is not practical.)

The Aspect Ratio[1] is listed at //Reel//MainPicture[1]/ScreenAspectRatio or //Reel//MainStereoscopicPicture[1]/ScreenAspectRatio[2] :

<Reel>
  …
  <MainPicture>
    <ScreenAspectRatio>1998 1080</ScreenAspectRatio>
  </MainPicture>
  …
</Reel>

The Pixel Array Size of the image container (used for projector setting) is listed at //Reel[1]//MainPictureStoredArea[3]:

<CompositionMetadataAsset xmlns=”http://www.smpte-ra.org/schemas/429-16/2014/CPL-Metadata”>
  …
  <MainPictureStoredArea>
    <Width>3996</Width>
    <Height>2160</Height>
  </MainPictureStoredArea>
  …
</CompositionMetadataAsset>

The Pixel Array Size of the content in the DCP (a function of pixel array size and aspect Ratio, used for masking) is listed at //Reel[1]//MainPictureActiveArea:

<CompositionMetadataAsset xmlns=”http://www.smpte-ra.org/schemas/429-16/2014/CPL-Metadata”>
  …
  <MainPictureActiveArea>
    <Width>2872</Width>
    <Height>2160</Height>
  </MainPictureActiveArea>
  …
</CompositionMetadataAsset>

  1. These values assume a SMPTE CPL. For IOP CPLs, the values for this element are the calulated aspect in a ratio over 0, rounded to the next hundredth, without the decimal, such as 185 0 ↩︎

  2. 2D content uses the MainPicture element; 3D content uses the MainStereoscopicPicture element (and they are placed at different locations within the Reel. ↩︎

  3. The CPL doesn’t have an explicit indicator of 2K or 4K content; it can be inferred from the dimensions recorded in MainPictureStoredArea. ↩︎

SPECIAL NOTE: Never use this labeling device with Trailers!

Trailers are almost always produced in both Flat and Scope versions regardless of the aspect ratio of the feature advertised. Quite often, the “non-native” format of the trailer is letterboxed or pillar-boxed. These “cross aspect ratio” trailers should never be identified using this method (F-239 or S-185) since theatres should not be encouraged to change masking for a single trailer on the playlist or this could inadvertently spoil the needed masking for the feature. (Changing masking from trailer to trailer is not practical.)

# DCNC Code
(For CTT)
Description ScreenAspectRatio Values
(For DCP Metadata)
MainPictureStoredArea Values
(For DCP Metadata)
Metadata Defining Document(s)
1 F Flat (1.85:1)
For 2K: "1998 1080"
For 4K: "3996 2160"
For 2k, Height: "1080", Width: "1998"
For 4K, Height: "2160", Width: "3996"
[SMPTE ST 429-16:2014]
[SMPTE ST 429-2:2019]
[SMPTE ST 428-12:2013]
2 S Scope (2.39:1)
For 2K: "2048 858"
For 4K: "4096 1716"
For 2k, Height: "858", Width: "2048"
For 4K, Height: "1716", Width: "4096"
[SMPTE ST 429-16:2014]
[SMPTE ST 429-2:2019]
[SMPTE ST 428-12:2013]
3 C Full Container (1.90:1)
For 2K: "2048 1080"
For 4K: "4096 2160"
For 2k, Height: "1080", Width: "2048"
For 4K, Height: "2160", Width: "4096"
[SMPTE ST 429-16:2014]
[SMPTE ST 429-2:2019]
[SMPTE ST 428-12:2013]