View Source FFmpex (ffmpex v0.10.0)

Create and execute ffmpeg CLI commands.

The API is a builder, building up the list of options per-file, per-stream(-per-file), and globally.

Note that adding options is backwards from using the ffmpeg CLI; when using ffmpeg CLI, you specify the options before each file. But with FFmpex (this library), you add the file/stream first, then add the relevant options afterward.

Example

import FFmpex
use FFmpex.Options

command =
  FFmpex.new_command
  |> add_global_option(option_y())
  |> add_input_file("/path/to/input.avi")
  |> add_output_file("/path/to/output.avi")
    |> add_stream_specifier(stream_type: :video)
      |> add_stream_option(option_b("64k"))
    |> add_file_option(option_maxrate("128k"))
    |> add_file_option(option_bufsize("64k"))

:ok = execute(command)

Link to this section Summary

Functions

Add a per-file option to the command.

Add a global option that applies to the entire command.

Add an input file to the command.

Add an output file to the command.

Add a per-stream option to the command.

Add a stream specifier to the most recent file. The stream specifier is used as a target for per-stream options.

Execute the command using ffmpeg CLI.

Begin a new blank (no options) ffmpeg command.

Prepares the command to be executed, by converting the %Command{} into proper parameters to be feeded to System.cmd/3 or Port.open/2.

Outputs to stdout, so it can be used directly from execute/1's output

Link to this section Functions

Link to this function

add_file_option(command, option)

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Add a per-file option to the command.

Applies to the most recently added file.

Link to this function

add_global_option(command, option)

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Add a global option that applies to the entire command.

Link to this function

add_input_file(command, file)

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Add an input file to the command.

Link to this function

add_output_file(command, file)

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Add an output file to the command.

Link to this function

add_stream_option(command, option)

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Add a per-stream option to the command.

Applies to the most recently added stream specifier, of the most recently added file.

Link to this function

add_stream_specifier(command, opts)

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Specs

add_stream_specifier(command :: FFmpex.Command.t(), opts :: Keyword.t()) ::
  FFmpex.Command.t()

Add a stream specifier to the most recent file. The stream specifier is used as a target for per-stream options.

Example

add_stream_specifier(command, stream_type: :video)

Options

  • :stream_index - 0-based integer index for the stream
  • :stream_type - One of :video, :video_without_pics, :audio, :subtitle, :data, :attachments
  • :program_id - ID for the program
  • :stream_id - Stream id (e.g. PID in MPEG-TS container)
  • :metadata_key - Match streams with the given metadata tag
  • :metadata_value - Match streams with the given metadata value. Must also specify :metadata_key.
  • :usable - Matches streams with usable configuration, the codec must be defined and the essential information such as video dimension or audio sample rate must be present.

Specs

execute(command :: FFmpex.Command.t()) ::
  {:ok, binary()}
  | {:error, {Collectable.t(), exit_status :: non_neg_integer()}}

Execute the command using ffmpeg CLI.

Returns {:ok, output} on success, or {:error, {cmd_output, exit_status}} on error.

Begin a new blank (no options) ffmpeg command.

Specs

prepare(command :: FFmpex.Command.t()) :: {binary() | nil, [binary()]}

Prepares the command to be executed, by converting the %Command{} into proper parameters to be feeded to System.cmd/3 or Port.open/2.

Under normal circumstances FFmpex.execute/1 should be used, use prepare only when converted args are needed to be feeded in a custom execution method.

Returns {ffmpeg_executable_path, list_of_args}.

Outputs to stdout, so it can be used directly from execute/1's output

this option cannot be used with output files