Video
Field & Frames - 2
Field mode in MediaStudio Pro
In MSP, field mode has 3 possible settings. They are Frame, Order A, and Order B. There are also 3 places where you select which field mode to use, plus one default setting.
You set the mode of an individual clip in the Clip menu using Field Options. Set it to Frame, Field Order A, or Field Order B according to how the clip was captured or created, and your capture card's field packing method.
You set the default for this mode in the Edit tab of the Preferences dialog, in the Frame type box. If you use the correct default you should never need to change the mode of an individual clip.
When creating a video file, you set field mode for the created file in the Options dialog. You also make a similar setting in the Preview Options dialog.
As a general rule, if you capture your clips using both fields, set the appropriate field order as the default for imported clips, and make the same setting in Preview and Create Video options. If you import clips in field mode but create video in frame mode then video creation will be extremely slow as every frame will be re-rendered. If, on the other hand, you have a particular reason to convert a field-mode AVI to frame mode, then this is the way to do it.
Deinterlace & Flicker reduction
In the Field Options dialog you can select Deinterlace when using a field-order, or Flicker reduction when frame-based.
- Deinterlace effectively uses only the first field in each frame, which you use when you want to eliminate motion blur.
- Flicker reduction can be used when you are creating a field-based result from a frame-based source, and causes two fields to be synthesised from each frame to minimise motion flicker.
Speed and direction changes
This is where it is very important that field mode AVIs are correctly identified. If you reduce the speed of a clip, MSP achieves the effect by repeating frames. If it treats the clip as frame mode, then it repeats a whole frame. If this frame consists of two fields A & B, the resulting field sequence is A-B-A-B. This will jitter visibly when replayed. If it treats the clip as field mode, it creates the sequence A-A-B-B. In other words, each field becomes one frame. This can actually be quite useful for other purposes, as we can see later.
A similar effect occurs if you reverse a clip. If the clip is treated as frame mode, the frames are played in reverse, but each pair of fields within the frame are still played forwards. The result looks horrible! Identifying the clip as field mode ensures that MSP reverses the order of the fields within the frames as well.
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