NAME

       Media::Convert::Pipe - class to generate ffmpeg command lines with Media::Convert::Asset

SYNOPSIS

         use Media::Convert::Asset;
         use Media::Convert::Pipe;

         my $input_audio = Media::Convert::Asset->new(url => $input_filename_audio);
         my $input_video = Media::Convert::Asset->new(url => $input_filename_video);
         my $output = Media::Convert::Asset->new(url => $output_filename);
         my $map_audio = Media::Convert::Map->new(input => $input_audio, type => "stream", choice => "audio");
         my $map_video = Media::Convert::Map->new(input => $input_video, type => "stream", choice => "video");
         my $pipe = Media::Convert::Pipe->new(inputs => [$input_audio, $input_video], map => [ $map_audio, $map_video ], output => $output);
         $pipe->run();

         # Or, if progress information is wanted:
         sub print_progress {
           my $percentage = shift;
           print "Transcoding progress: $percentage\r";
         }
         $pipe->progress(\&print_progress);
         $pipe->run();

DESCRIPTION

       "Media::Convert::Pipe" is the class in the "Media::Convert" package which does most of the
       hard work inside "Media::Convert". It generates and runs the ffmpeg command line,
       capturing the output where required.

       "Media::Convert::Pipe" will compare the properties of the input "Media::Convert::Asset"
       objects against those of the output "Media::Convert::Asset" object, and will add the
       necessary parameters to the ffmpeg command line to convert the audio/video material in the
       input file to the format required by the output file.

ATTRIBUTES

       The following attributes are supported by "Media::Convert::Pipe".

   inputs
       The objects to read from. Must be "Media::Convert::Asset" objects. If more than one object
       is passed, a value for the "map" attribute may be required to tell ffmpeg which
       audio/video stream to read from which file.

       More input objects can be added using the "add_input" method, and they can all be removed
       using the "clear_inputs" object.

   output
       The object to write to. Must be a "Media::Convert::Asset" object.  Required.

       If any properties differ between the input objects and the output object (e.g., the codec,
       pixel format, audio sample frequency, video resolution, etc etc etc),
       "Media::Convert::Pipe" will add the necessary command-line options to the ffmpeg command
       line to convert the video from the input file to the output file.

   map
       Array of "Media::Convert::Map" objects, used to manipulate which audio and video streams
       exactly will be written to the output file (and in which order, etc).

       For more info: see Media::Convert::Map.

       Maps can be cleared with "clear_map" and added to with "add_map".

   vcopy
       Boolean. If true, explicitly tell "Media::Convert" to copy video without transcoding it.

       Normally, "Media::Convert" should not request a transcode if all attributes of the input
       file and the output file are exactly the same.  Getting this right may sometimes be
       problematic, however. In such cases, it can be good to explicitly say that the video
       should not be transcoded. That's what this property is for.

   acopy
       The same as "vcopy", but for audio rather than video.

   vskip
       Tell "Media::Convert" that the output file should not contain any video (i.e., that it
       should skip handling of any video). This is implied if the output container does not
       support video streams (e.g., the .wav format), but is required if it does.

   askip
       The same as "vskip", but for audio rather than video.

   multipass
       Boolean. If true, the "run" method performs a two-pass encode, rather than a single-pass
       encode.

       Two-pass encodes will generate a better end result, but require more time to perform.

   progress
       Normally, "Media::Convert::Pipe" shows (and runs) the ffmpeg command.  Any output of the
       ffmpeg command is shown on stdout.

       If this attribute is set to a coderef, then the following happens:

       The ffmpeg command line that is executed gains "-progress /dev/stdout" parameters
       The output of the ffmpeg command is parsed, and the completion percentage calculated (and
       all other output suppressed),
       The coderef that was passed to this attribute is executed with the completion percentage
       as the only parameter whenever the percentage changes.

METHODS

   run
       Run the ffmpeg command.

       If this method is not run at least once, the object's destructor will issue a warning.

POD ERRORS

       Hey! The above document had some coding errors, which are explained below:

       Around line 194:
           =over should be: '=over' or '=over positive_number'