Image Info Structure
Whenever FxFactory gives you the option to map an input from the host to an image input port in the Quartz composition, it will also give you a chance to set up a secondary (and optional) mapping, called “Image Info”.
If a standard Image mapping simply transfers image contents from the host to your composition, the “Image Info” mapping is meant to transfer metadata about that image.
Extract the values in this structure exclusively through the FxFactory Image Info patch. The available outputs are as follows:
- Pixels Wide and Pixels High contain the image dimensions.
- Pixel Aspect Ratio contains the pixel aspect of the image, e.g. 1.33 for an anamorphic HD frame with resolution of 1440×1080 pixels and display aspect of 16:9.
- Display Aspect Ratio contains the aspect ratio at which the image is ultimately displayed to the viewer, usually one of 4:3, 19:9, 19:10.
- Field Order contains a numeric value which is equal to 0 if the image source is progressive, 1 if the image source is interlaced and the upper field comes first, 2 if the image source is interlaced and the lower field comes first.
- Field contains a value which is equal to 0 if the image contains progressive data, 1 if the image represents the upper field, 2 if the image represents the lower field.
- Pixel Format a value which represents the pixel format of the image: 0 for RGB + alpha images 1).
- Bits per Pixel number of bits used to represent each pixel, e.g. 32 for 8-bit RGBA, 64 for 16-bit half-float or 128 for 32-bit float.
- Scaling X (native to square) and Scaling Y (native to square) scaling factor necessary to transform the input image from its native pixel aspect ratio to the square pixel aspect ratio.
- Scaling X (square to native) and Scaling Y (square to native) scaling factor necessary to transform the input image from a square pixel aspect ratio back to its native pixel aspect ratio.
- Margin Pixels Wide and Margin Pixels High: when a filter supports frame expansion and the user has opted to make the output dimensions larger than the original clip, these outputs contain the number of extra pixels available on each side of the horizontal and vertical axes, respectively.
| Notice that a number of other outputs have been deprecated. These output values are no longer filled with meaningful values as of FxFactory version 7. Plug-ins can no longer rely on these outputs. |
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The “Scaling” outputs are meant to provide assistance to developers who wish to develop plug-ins that can handle footage of any pixel aspect ratio. It is common to apply a transform from native to square at the beginning of an effect chain, and convert the final result back to its native pixel aspect ratio as the last step before rendering the output.
