Metadata is a set of information about an image embedded in the image file. This information may include the image’s original bit depth, width, and height, for example. It can be attached to the file by the camera used to shoot the images, and/or edited later.
When Nuke loads an image, it reads in the metadata embedded in the image. The metadata is then passed down the node tree so you can view and use it at any point in your script. For example, you can reference metadata via expressions. You can also edit or delete existing metadata, add new metadata to a file, and write the resulting metadata out to files.
NOTE: Metadata for QuickTime files does not show gamma or bit depth.
NOTE: When using a Merge node, you can choose which input’s metadata to pass down the tree. In the Merge controls, set metadata from to either A or B.
In the MetaData menu of the Toolbar, Nuke features five nodes that help you work with file metadata:
• ViewMetaData lets you inspect the metadata passed down by the input node. See Viewing Metadata.
• CompareMetaData lets you compare the metadata between two inputs and view the differences. See Comparing Metadata Between Inputs.
• ModifyMetaData lets you edit existing metadata in the input stream, add metadata into the stream, and delete metadata from the stream. See Modifying Metadata.
• CopyMetaData lets you copy metadata from one input to another and filter metadata to exclude some of it. See Copying Metadata from One Input to Another and Filtering Metadata.
• AddTimeCode lets you add a timecode to the metadata passed down by the input node. See Adding a Time Code to Metadata.