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.\"
.IX Title "Media::Convert::AvSync 3pm"
.TH Media::Convert::AvSync 3pm "2023-03-07" "perl v5.36.0" "User Contributed Perl Documentation"
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.SH "NAME"
Media::Convert::AvSync \- Helper module to fix A/V synchronization issues.
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 2
\&  use Media::Convert::Asset;
\&  use Media::Convert::AvSync;
\&  
\&  my $input = Media::Convert::Asset\->new(url => $input_filename);
\&  my $output = Media::Convert::Asset\->new(url => $output_filename);
\&  Media::Convert::AvSync\->new(input => $input, output => $output, audio_delay => 0.1)\->run();
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Media::Convert::AvSync is a higher-level helper module to correct
audio/video synchronization issues.
.PP
It does this by instructing ffmpeg to read the input asset twice (once
for audio, once for video), and to apply a time offset to the audio
stream. This offset may be negative, in case audio precedes video.
.PP
Note that after A/V sync correction, the asset file will be reduced in
length by twice the length of the correction value; this is because
otherwise, in the case of audio preceding video, the resulting media
file would end up with a snippet of audio with no video at the start,
and one of video with no audio at the end (and vice versa for a
correction value for video preceding audio).
.SH "ATTRIBUTES"
.IX Header "ATTRIBUTES"
The following attributes are supported by Media::Convert::AvSync:
.SS "input"
.IX Subsection "input"
The input asset. Must be a Media::Convert::Asset object.
.SS "output"
.IX Subsection "output"
The output asset. Must be a Media::Convert::Asset object.
.SS "audio_delay"
.IX Subsection "audio_delay"
The delay that should be applied to the audio in the input asset. Should
be expressed in seconds; may be a fractional and/or negative value.
.PP
Postive values delay the audio; negative values delay the video.