README.md

<h1 align="center">vtc-ex</h1>
<p align="center">
    <img height=150 class="heightSet" align="center" src="https://raw.githubusercontent.com/opencinemac/vtc-py/master/zdocs/source/_static/logo1.svg"/>
</p>
<p align="center">A SMPTE Timecode Library for Elixir</p>
<p align="center">
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</p>
<p align="center">
    <a href="https://hex.pm/packages/vtc"><img src="https://img.shields.io/hexpm/v/vtc.svg" alt="PyPI version" height="18"></a>
    <a href="https://hexdocs.pm/vtc/readme.html"><img src="https://img.shields.io/badge/docs-hexdocs.pm-blue" alt="Documentation"></a>
</p>

## Demo

A small preview of what `Vtc` has to offer. Note that printing statements like 
`inspect/1` have been elided from the examples below.

`Vtc` represents specific frames in a video stream as [Framestamps](`Vtc.Framestamp`), 
which can [parsed](Vtc.Framestamp.html#parse) from a number of different formats, 
including SMPTE timecode, frame count, and physical film length measured in 
feet and frames:

```elixir
iex> Framestamp.with_seconds!(1.5, Rates.f23_98())
"<00:05:23:04 <23.98 NTSC>>"
iex> stamp = Framestamp.with_frames!("17:23:13:02", Rates.f23_98())
"<17:23:00:02 <23.98 NTSC>>"
```

Once in a [Framestamp](`Vtc.Framestamp`) struct, you 
[convert](Vtc.Framestamp.html#convert) to any of the supported formats:

```elixir
iex> Framestamp.smpte_timecode(stamp)
"00:05:23:04"
iex> Framestamp.frames(stamp)
1501922
iex> Framestamp.feet_and_frames(stamp)
"<93889+10 :ff35mm_4perf>"
```

[Comparisons](Vtc.Framestamp.html#compare) and 
[kernel sorting](Vtc.Framestamp.html#module-sorting-support) are supported, with many 
helper functions for specific comparisons:

```elixir
iex> Framestamp.compare(stamp, "02:00:00:00")
:gt
iex> Framestamp.gt?(stamp, "02:00:00:00")
true
iex> stamp_01 = Framestamp.with_frames!("01:00:00:00", Rates.f23_98())
iex> stamp_02 = Framestamp.with_frames!("02:00:00:00", Rates.f23_98())
iex> data_01 = %{id: 2, tc: stamp_01}
iex> data_02 = %{id: 1, tc: stamp_02}
iex> [data_02, data_01] |> Enum.sort_by(& &1.tc, Framestamp) |> inspect()
"[%{id: 2, tc: <01:00:00:00 <23.98 NTSC>>}, %{id: 1, tc: <02:00:00:00 <23.98 NTSC>>}]"
```

All sensible [arithmetic](Vtc.Framestamp.html#arithmetic) operations are provided, such 
as addition, subtraction, and multiplication:

```elixir
iex> stamp = Framestamp.add(tc, "01:00:00:00")
"<18:23:13:02 <23.98 NTSC>>"
```

You can even use native operators within special [eval/2](Vtc.Framestamp.html#eval/2) 
blocks:

```elixir
iex> Framestamp.eval at: 23.98 do
iex>   stamp + "00:30:00:00" * 2 - "00:15:00:00"
iex> end
"<19:08:13:02 <23.98 NTSC>>"
```

[Ranges](`Vtc.Range`) let you operate on in/out points, for instance, finding the 
overlapping area between two ranges:

```elixir
iex> a_in = Framestamp.with_frames!("01:00:00:00", Rates.f23_98())
iex> a = Range.new!(a_in, "02:00:00:00")
"<01:00:00:00 - 02:00:00:00 :exclusive <23.98 NTSC>>"
iex> b_in = Framestamp.with_frames!("01:45:00:00", Rates.f23_98())
iex> b = Range.new!(b_in, "02:30:00:00")
"<01:45:00:00 - 02:30:00:00 :exclusive <23.98 NTSC>>"
iex> Range.intersection!(a, b)
"<01:45:00:00 - 02:00:00:00 :exclusive <23.98 NTSC>>"
```

## Further Reading

Check out the [Quickstart Guide](quickstart.html) for a more in 
depth walkthrough of what `Vtc` can do, or dive straight into the 
[API Reference](api-reference.html).

## Goals

- Offer a comprehensive set of tools for parsing, manipulating and rendering timecode
  with all it's quirks and incarnations.

- Define an intuitive, idiomatic Elixir API.

- Do all calculations in Rational representation, so there is both no drift or rounding 
  errors when manipulating NTSC timecode, and we can represent time as finely as 
  possible rather than being limited to the granularity of frame numbers.

- Be approachable for newcomers to the timecode problem space. Each function and concept
  in the [API Reference](api-reference.html) includes a primer on what it is and where 
  it is used in Film and Television workflow.

- Offer a flexible set of tools that support both rigorous, production-quality code and
  quick scratch scripts.

## Features

- SMPTE Conventions:
    - [X] NTSC
    - [X] Drop-Frame
    - [ ] Interlaced timecode
- Timecode Representations:
    - [X] Framestamp  | 18018/5 seconds @ 24000/1001
    - [X] Timecode    | '01:00:00:00'
    - [X] Frames      | 86400
    - [X] Seconds     | 3600.0
    - [X] Runtime     | '01:00:00.0'
    - [X] Rational    | 18018/5
    - [X] Feet+Frames | '5400+00'
        - [X] 35mm, 4-perf
        - [ ] 35mm, 3-perf
        - [X] 35mm, 2-perf
        - [X] 16mm
    - [X] Premiere Ticks | 15240960000000
- Operations:
    - [X] Comparisons (==, <, <=, >, >=)
    - [X] Add
    - [X] Subtract
    - [X] Scale (multiply and divide)
    - [X] Divmod
    - [X] Modulo
    - [X] Negative
    - [X] Absolute
    - [X] Rebase (recalculate frame count at new framerate)
    - [X] Native Operator Evaluation
- Flexible Parsing:
    - [X] Partial timecodes      | '1:12'
    - [X] Partial runtimes       | '1.5'
    - [X] Negative string values | '-1:12', '-3+00'
    - [X] Poorly formatted SMPTE timecode    | '1:13:4'
- [X] Built-in consts for common framerates.
- [X] Configurable rounding options.
- [X] Support for standard library sorting behavior.
- [X] Range type for working with and comparing frame ranges.
    - [X] Overlap between ranges
    - [X] Distance between ranges
    - [X] Inclusive and exclusive ranges
- [X] Postgres Composite Types with Ecto and Postgrex:
    - Rational[X]
      - [X] Native comparison operators
      - [X] Native arithmatic operators
      - [X] Native indexing support
    - Framerate[X]
    - Timecode[X]
      - [ ] Native comparison operators
      - [ ] Native arithmatic operators
      - [ ] Native indexing Support
      - [ ] Native inspection functions
    - Range
      - [ ] Native indexing support
      - [ ] Native inspection functions

## Attributions

Drop-frame calculations adapted from 
[David Heidelberger's blog](https://www.davidheidelberger.com/2010/06/10/drop-frame-timecode/).

35mm, 2perf and 16mm format support based on 
[Jamie Hardt's work for vtc-rs](https://github.com/opencinemac/vtc-rs/pull/8).

Logo made by Freepik from [www.flaticon.com](https://www.flaticon.com/).

## Installation

If [available in Hex](https://hex.pm/docs/publish), the package can be installed
by adding `vtc` to your list of dependencies in `mix.exs`:

```elixir
def deps do
  [
    {:vtc, "~> 0.12"}
  ]
end
```