I would suggest:

use IO::Pipe;
my $pipe = IO::Pipe->new();
$pipe->writer(qw(ffmpeg -i pipe:0));
print $pipe $mp3;

[download]

to avoid the shell being used to launch ffmpeg.

In reply to Re^2: Passing an in memory scalar to an external command as an argument by RonW
in thread Passing an in memory scalar to an external command as an argument by Rodster001

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