Connecting Kronos

To connect Kronos:

Select Time > Kronos to insert a Kronos node after the sequence you want to retime.

The Input Range is set automatically by the source clip when you first create the node. After that, it is only updated if you click Reset.

If you intend to use Output Speed or Frame timing, attach a Viewer to the output of the Kronos node,

If you intend to use Input Speed timing, attach a Viewer before the Kronos node.

Enable Use GPU if available to render output on the Local GPU specified, if available, rather than the CPU.

Note: For more information on GPU support, see the Release Notes for your version of Nuke.

Select the channels you want to apply the retime to using the channels dropdown. Kronos retimes all channels by default.

If your sequence is composed of a foreground object moving over a background, the motion estimation is likely to get confused at the edge between the two. To fix this, add a matte of the foreground region to the Matte input. Then, use Matte Channel in the Kronos properties to select which component of the matte to use.

This forces the motion of the foreground to be calculated separately to the motion of the background and so should produce fewer artifacts in the retimed sequence.

If the motion in your input sequence has been estimated before (for example, using VectorGenerator or third-party software), you can supply the motion vectors to the Background Vectors (BgVecs) and Foreground Vectors (FgVecs) inputs to save processing time.

Note: The BgVecs input appears as an arrowhead on the side of the node.

If you have separate vectors for the background and foreground, you should connect them to the appropriate inputs and supply the matte that was used to generate them to the Matte input. If you have a single set of vectors, you should connect it to the FgVecs input.

You can set Output in the Kronos controls to:

• Result - displays both the foreground and background retimed footage.

• Matte - displays the retimed Matte input.

• Foreground - displays the retimed foreground. The background regions outside the matte input may show garbage.

• Background - displays the retimed background. The foreground regions inside the matte input may show garbage.

If your Source sequence is very noisy and interfering with the motion estimation, you can supply a smoothed version of the sequence in the MoSrc input. When a MoSrc input is connected, motion vectors are calculated from that sequence and applied to the Source sequence.

Proceed to Retiming a Sequence.