OTIO media references and effects

A Clip points at its media through one or more media references, and any item can carry effects.

Fields of every media reference

These belong to MediaReference.1, the base type, and to the four types below.

Adds target_url, a string: the address of the media.

No extra fields. It stands for media that cannot be found.

Field	Type	Meaning
`generator_kind`	string	Which generator.
`parameters`	dictionary	Its settings.

Numbered image files. The address of frame n is built from the fields below.

Field	Type	Library default	Meaning
`target_url_base`	string	empty	Everything up to the file name.
`name_prefix`	string	empty	Everything in the file name before the frame number.
`name_suffix`	string	empty	Everything after the frame number.
`start_frame`	integer	1	The first frame number used in file names.
`frame_step`	integer	1	Step between frame numbers in file names.
`rate`	double	1	Frame rate if every frame in the sequence were played.
`frame_zero_padding`	integer	0	Digits to pad the frame number to.
`missing_frame_policy`	integer	error	What to do with frames not found during playback or rendering.

Value	Name	Meaning
0	`error`	Stop and raise an error.
1	`hold`	Hold the last available frame before the missing one.
2	`black`	Use a black frame instead.

All effect types have name, metadata, effect_name (a string) and enabled (a boolean: if false, the effect is omitted).

Schema	Extra field	Meaning
`Effect.1`		A general effect.
`TimeEffect.1`		An effect on time.
`LinearTimeWarp.1`	`time_scalar` (double, default 1.0)	Applied to the clip: 2.0 is double speed and 0.5 is half speed. The item’s duration does not change.
`FreezeFrame.1`	`time_scalar`	A freeze frame, written with the same field as a linear time warp.