Defines a composite type for storing rational values as a PgRational real-world playback seconds, PgFramerate pair.

These values are cast to Framestamp structs for use in application code.

The composite types is defined as follows:

CREATE TYPE framestamp AS (
  __seconds_n bigint,
  __seconds_d bigint,
  __rate_n bigint,
  __rate_d bigint,
  __rate_tags framerate_tags[]
);

Field Access

framestamp's inner fields are considered semi-private to end-users. For working with the seconds / rate values, see create_func_seconds/0, create_func_rate/0, which create Postgres functions to act as getter functions for working with inner framestamp data.

SELECT (18018, 5, 24000, 1001, '{non_drop}')::framestamp

field-migrations

Field migrations

You can create framerate fields during a migration like so:

alias Vtc.Framestamp

create table("events") do
  add(:in, Framestamp.type())
  add(:out, Framestamp.type())
end

Framestamp re-exports the Ecto.Type implementation of this module, and can be used any place this module would be used.

schema-fields

Schema fields

Then in your schema module:

defmodule MyApp.Event do
@moduledoc false
use Ecto.Schema

alias Vtc.Framestamp

@type t() :: %__MODULE__{
        in: Framestamp.t(),
        out: Framestamp.t()
      }

schema "events" do
  field(:in, Framestamp)
  field(:out, Framestamp)
end

changesets

Changesets

With the above setup, changesets should just work:

def changeset(schema, attrs) do
  schema
  |> Changeset.cast(attrs, [:in, :out])
  |> Changeset.validate_required([:in, :out])
end

Framerate values can be cast from the following values in changesets:

• Framestamp structs.

• Maps with the following format:

  {
    "smpte_timecode": "01:00:00:00",
    "rate": {
      "playback": [24000, 1001],
      "ntsc": "non_drop"
    }
  }

  Where smpte_timecode is properly formatted SMPTE timecode string and playback is a map value supported by PgFramerate changeset casts.

fragments

Fragments

Framestamp values must be explicitly cast using type/2:

framestamp = Framestamp.with_frames!("01:00:00:00", Rates.f23_98())
query = Query.from(f in fragment("SELECT ? as r", type(^framestamp, Framestamp)), select: f.r)