NAME
    App::FfmpegUtils - Utilities related to ffmpeg

VERSION
    This document describes version 0.003 of App::FfmpegUtils (from Perl
    distribution App-FfmpegUtils), released on 2020-06-04.

FUNCTIONS
  reencode_video
    Usage:

     reencode_video(%args) -> [status, msg, payload, meta]

    Re-encode video (using ffmpeg and H.264 codec).

    This utility runs ffmpeg to re-encode your video files. It is a wrapper
    to simplify invocation of ffmpeg. It selects the appropriate ffmpeg
    options for you, allows you to specify multiple files, and picks
    appropriate output filenames. It also sports a "--dry-run" option to let
    you see ffmpeg options to be used without actually running ffmpeg.

    This utility is usually used to reduce the file size (and optionally
    video width/height) of videos so they are smaller, while minimizing
    quality loss. The default setting is roughly similar to how Google
    Photos encodes videos (max 1080p).

    The default settings are:

     -v:c libx264
     -preset veryslow (to get the best compression rate, but with the slowest encoding time)
     -crf 28 (0-51, subjectively sane is 18-28, 18 ~ visually lossless, 28 ~ visually acceptable)

    when a downsizing is requested (using the "--downsize-to" option), this
    utility first checks each input video if it is indeed larger than the
    requested final size. If it is, then the "-vf scale" option is added.
    This utility also calculates a valid size for ffmpeg, since using "-vf
    scale=-1:720" sometimes results in failure due to odd number.

    Audio streams are copied, not re-encoded.

    Output filenames are:

     ORIGINAL_NAME.crf28.mp4

    or (if downsizing is done):

     ORIGINAL_NAME.480p-crf28.mp4

    This function is not exported.

    This function supports dry-run operation.

    Arguments ('*' denotes required arguments):

    *   crf => *int*

    *   downsize_to => *str* (default: "1080p")

        Downsizing will only be done if the input video is indeed larger
        then the target downsize.

        To disable downsizing, set "--downsize-to" to '' (empty string), or
        specify on "--dont-downsize" on the CLI.

    *   ffmpeg_path => *filename*

    *   files* => *array[filename]*

    Special arguments:

    *   -dry_run => *bool*

        Pass -dry_run=>1 to enable simulation mode.

    Returns an enveloped result (an array).

    First element (status) is an integer containing HTTP status code (200
    means OK, 4xx caller error, 5xx function error). Second element (msg) is
    a string containing error message, or 'OK' if status is 200. Third
    element (payload) is optional, the actual result. Fourth element (meta)
    is called result metadata and is optional, a hash that contains extra
    information.

    Return value: (any)

HOMEPAGE
    Please visit the project's homepage at
    <https://metacpan.org/release/App-FfmpegUtils>.

SOURCE
    Source repository is at
    <https://github.com/perlancar/perl-App-FfmpegUtils>.

BUGS
    Please report any bugs or feature requests on the bugtracker website
    <https://rt.cpan.org/Public/Dist/Display.html?Name=App-FfmpegUtils>

    When submitting a bug or request, please include a test-file or a patch
    to an existing test-file that illustrates the bug or desired feature.

AUTHOR
    perlancar <perlancar@cpan.org>

COPYRIGHT AND LICENSE
    This software is copyright (c) 2020 by perlancar@cpan.org.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.

