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App-FfmpegUtils-0.011
River stage one • 1 direct dependent • 1 total dependent
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/ App::FfmpegUtils

NAME

App::FfmpegUtils - Utilities related to ffmpeg

VERSION

This document describes version 0.011 of App::FfmpegUtils (from Perl distribution App-FfmpegUtils), released on 2022-09-21.

FUNCTIONS

cut_video_by_duration

Usage:

 cut_video_by_duration(%args) -> [$status_code, $reason, $payload, \%result_meta]

Get a portion (time range) of a video.

This utility uses ffmpeg (particularly the -t and -ss) option to get a portion (time range) of a video. It is a convenient wrapper of ffmpeg for this particular task. You can specify start time and end time, or start time and duration. It automatically chooses a filename if you don't specify one.

This function is not exported.

This function supports dry-run operation.

Arguments ('*' denotes required arguments):

  • file* => filename

  • start* => duration

Special arguments:

  • -dry_run => bool

    Pass -dry_run=>1 to enable simulation mode.

Returns an enveloped result (an array).

First element ($status_code) is an integer containing HTTP-like status code (200 means OK, 4xx caller error, 5xx function error). Second element ($reason) is a string containing error message, or something like "OK" if status is 200. Third element ($payload) is the actual result, but usually not present when enveloped result is an error response ($status_code is not 2xx). Fourth element (%result_meta) is called result metadata and is optional, a hash that contains extra information, much like how HTTP response headers provide additional metadata.

Return value: (any)

reencode_video_with_libx264

Usage:

 reencode_video_with_libx264(%args) -> [$status_code, $reason, $payload, \%result_meta]

Re-encode video (using ffmpeg and libx264).

This utility runs ffmpeg to re-encode your video files using the libx264 codec. 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. Smartphone-produced videos are often high bitrate (e.g. >10-20Mbit) and not yet well compressed, so they make a good input for this utility. 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):

  • audio_sample_rate => uint

    Set audio sample rate, in Hz.

  • crf => int

  • ffmpeg_path => filename

  • files* => array[filename]

  • frame_rate => ufloat

    Set frame rate, in fps.

  • preset => str (default: "veryslow")

  • scale => str (default: "1080^>")

    Scale video to specified size. See Math::Image::CalcResized or calc-image-resized-size for more details on scale specification. Some examples include:

    The default is 1080^> which means to shrink to 1080p if video size is larger than 1080p.

    To disable scaling, set --scale to '' (empty string), or specify --dont-scale on the CLI.

Special arguments:

  • -dry_run => bool

    Pass -dry_run=>1 to enable simulation mode.

Returns an enveloped result (an array).

First element ($status_code) is an integer containing HTTP-like status code (200 means OK, 4xx caller error, 5xx function error). Second element ($reason) is a string containing error message, or something like "OK" if status is 200. Third element ($payload) is the actual result, but usually not present when enveloped result is an error response ($status_code is not 2xx). Fourth element (%result_meta) is called result metadata and is optional, a hash that contains extra information, much like how HTTP response headers provide additional metadata.

Return value: (any)

split_video_by_duration

Usage:

 split_video_by_duration(%args) -> [$status_code, $reason, $payload, \%result_meta]

Split video by duration into parts.

This utility uses ffmpeg (particularly the -t and -ss) option to split a longer video into shorter videos. For example, if you have long.mp4 with duration of 1h12m and you run it through this utility with --every 15min then you will have 5 new video files: long.1of5.mp4 (15min), long.2of5.mp4 (15min), long.3of5.mp4 (15min), long.4of5.mp4 (15min), and long.5of5.mp4 (12min).

This function is not exported.

This function supports dry-run operation.

Arguments ('*' denotes required arguments):

  • copy => bool

    Whether to use the "copy" codec (fast but produces inaccurate timings).

  • every* => duration

  • files* => array[filename]

Special arguments:

  • -dry_run => bool

    Pass -dry_run=>1 to enable simulation mode.

Returns an enveloped result (an array).

First element ($status_code) is an integer containing HTTP-like status code (200 means OK, 4xx caller error, 5xx function error). Second element ($reason) is a string containing error message, or something like "OK" if status is 200. Third element ($payload) is the actual result, but usually not present when enveloped result is an error response ($status_code is not 2xx). Fourth element (%result_meta) is called result metadata and is optional, a hash that contains extra information, much like how HTTP response headers provide additional metadata.

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.

AUTHOR

perlancar <perlancar@cpan.org>

CONTRIBUTING

To contribute, you can send patches by email/via RT, or send pull requests on GitHub.

Most of the time, you don't need to build the distribution yourself. You can simply modify the code, then test via:

 % prove -l

If you want to build the distribution (e.g. to try to install it locally on your system), you can install Dist::Zilla, Dist::Zilla::PluginBundle::Author::PERLANCAR, Pod::Weaver::PluginBundle::Author::PERLANCAR, and sometimes one or two other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond that are considered a bug and can be reported to me.

COPYRIGHT AND LICENSE

This software is copyright (c) 2022, 2020 by perlancar <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.

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.