This page describes filters, which process a picture. Examples are a colour correction, a crop, a chroma key and sharpening. You can set filters at three levels, and the most important decision is which level to use.
The three levels
| Level | Where to set it | Applies to |
|---|---|---|
| On a source | Scene builder → right-click the source → Source filters… | That source, in that scene |
| On a scene | Scene builder → right-click the picture → Scene filters… | Everything in that scene |
| On a playout | Right-click the monitor panel → Scene filters… | Everything the playout sends out, whichever cue is on air |
The third level is easy to miss, but it is often the one you need: a correction for the whole output, and not for one item in the rundown.
Choosing the level
To choose the level, decide what the filter must correct:
- A property of the file, such as a clip that is too dark, or a logo with a green background that must be removed. Set the filter on the source.
- A property of the scene, when everything in the scene needs the same treatment. Set the filter on the scene.
- A property of the chain, such as a projector with a pale picture, or a mixer that expects a different level. Set the filter on the playout.
If you set a correction for the chain on a source, you must repeat it on every source, and you will forget it on a source that is added later.
What filters cost
Each filter needs processing for every frame. One correction on a playout costs little, but four filters on a playout that also encodes a stream cost much more.
If the status bar reports missed frames after you add filters, the filters are the cause. The best solution is then usually to correct the material itself, instead of processing it live.
Practical notes
Judge a filter on the output, not in the preview. The thing you correct is usually further along the chain than your own screen.
Write down what you changed. A colour correction on a playout is not visible in the rundown, and the program keeps it after a restart. A year later, nobody remembers it, so the filter on the panel is the one that causes the most confusion.
A filter is not an overlay. To show graphics over the picture, build a scene with the graphics on top.