View Source Vtc.Framerate (vtc v0.17.5)
The rate at which a video file frames are played back, measured in frames-per-second (24/1 = 24 frames-per-second). For more on framerate and why Vtc chooses to represent it as a rational number, see NTSC: Framerate vs timebase and The Rational Rationale
struct-fields
Struct Fields
playback: The rational representation of the real-world playback speed as a fraction in frames-per-second.ntsc: Atom representing which, if any, NTSC convention this framerate adheres to.
using-as-an-ecto-type
Using as an Ecto Type
See PgFramerate for information on how to use
Framerate in your postgres database as a native type.
Link to this section Summary
Parse
Creates a new Framerate with a playback speed or timebase.
As new/2 but raises an error instead.
Inspect
Returns true if the value represents and NTSC framerate.
The rational representation of the SMPTE timecode's 'logical speed'. For more on timebase and it's relationship to framerate, see: NTSC: Framerate vs timebase.
Ecto Migrations
The database type for PgFramerate.
Functions
Callback implementation for Ecto.Type.embed_as/1.
Callback implementation for Ecto.Type.equal?/2.
Link to this section Types
@type new_opt_coerce_ntsc?() :: boolean() | :if_trunc
Type for new/2 coerce_ntsc? option.
@type new_opts() :: [ ntsc: ntsc(), coerce_ntsc?: new_opt_coerce_ntsc?(), allow_float?: boolean(), invert?: boolean() ]
@type ntsc() :: :non_drop | :drop | nil
Enum of Ntsc types.
values
Values
:non_dropA non-drop NTSC value.:dropA drop-frame ntsc value.nil: Not an NTSC value
For more information on NTSC standards and framerate conventions, see Frame.io's blog post on the subject.
@type parse_result() :: {:ok, t()} | {:error, Vtc.Framerate.ParseError.t()}
Type returned by new/2
Type of Framerate
Link to this section Parse
@spec new(Ratio.t() | number() | String.t(), new_opts()) :: parse_result()
Creates a new Framerate with a playback speed or timebase.
arguments
Arguments
rate: Either the playback rate or timebase. For NTSC framerates, the value will be rounded to the nearest correct value.
options
Options
ntsc: Atom representing the which (or whether an) NTSC standard is being used. Default:nil.coerce_ntsc?: If and how to coerce values to the nearest NTSC value. Default:falsetrue: Ifntscis non-nil, values will be coerced to the nearest valid NTSC rate. So24would be coerced to24000/1001, as would23.98. This option must be set to true whenntscis non-nil and a float is passed.false: Do not coerce value. Passed value must conform exactly to a valid NTSC framerate.:if_trunc: Will coerce value to a valid NTSC rate using thentscopt value if the below criteria are met. If the criteria are not met, the value will be parsed as-is withntscset tonil:The incoming value is a float, with two or more significant digits that match the truncated+rounded form. So
23.98and23.976would be coerced to24000/1001but23.99and23.96would both be left as-is.The incoming value is a Rational, and precisely represents a valid NTSC framerate.
The incoming value is a Rational, that when cast to float, matches the above criteria.
The incoming value is a string representation of any of the above.
allow_fractional_float?: Iftrue, will allow non-integer float values to be converted to Rational values when parsing framerates. Can be combined with:if_truncto parse floating point values, coercing to NTSC if it appears to be an abbreviated NTSC value.
invert?: Iftrue, the resulting rationalratevalue will be flipped so that1/24becomes24/1. This can be helpful when you are parsing a rate given in seconds-per-frame rather than frames-per-second. Default:false.
As new/2 but raises an error instead.
Link to this section Inspect
Returns true if the value represents and NTSC framerate.
Will return true on a Framerate with an :ntsc value of :non_drop and :drop.
The rational representation of the SMPTE timecode's 'logical speed'. For more on timebase and it's relationship to framerate, see: NTSC: Framerate vs timebase.
Returned value is in frames-per-second.
Link to this section Ecto Migrations
@spec type() :: atom()
The database type for PgFramerate.
Can be used in migrations as the fields type.
Link to this section Functions
Callback implementation for Ecto.Type.embed_as/1.
Callback implementation for Ecto.Type.equal?/2.