#!/usr/bin/env perl
# Copyright (c) 2012 Nicolas George
#
# This file is part of FFmpeg.
#
# FFmpeg is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# FFmpeg is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
=head1 NAME
make_chlayout_test - produce a multichannel test file with the channels
clearly identified
=head1 SYNOPSIS
tools/make_chlayout_test I<channels> I<out_options>
=head1 DESCRIPTION
This script uses B<ffmpeg> and B<libflite> to produce a file with audio
channels clearly identified by their name. The resulting file can be used to
check that the layout and order of channels is correctly handled by a piece
of software, either a part of B<FFmpeg> or not.
I<channels> is a list of channels or channel layouts, separated by '+'.
I<out_options> is a list of valid ffmpeg outout options, including the
output file.
Note that some output codecs or formats can not handle arbitrary channel
layout.
This script requires a B<ffmpeg> binary, either in the source tree or in the
search path; it must have the flite audio source enabled.
=head1 EXAMPLES
Check that the speakers are correctly plugged:
tools/make_chlayout_test FL+FR -f alsa default
Produce a 5.1 FLAC file:
tools/make_chlayout_test 5.1 surround.flac
=cut
use strict;
use warnings;
use Getopt::Long ":config" => "require_order";
use Pod::Usage;
GetOptions (
"help|usage|?|h" => sub { pod2usage({ -verbose => 1, -exitval => 0 }) },
"manpage|m" => sub { pod2usage({ -verbose => 2, -exitval => 0 }) },
) and @ARGV >= 2 or pod2usage({ -verbose => 1, -exitval => 1 });
my $channels = shift @ARGV;
my @out_options = @ARGV;
my $ffmpeg = exists $ENV{FFMPEG} ? $ENV{FFMPEG} :
$0 =~ /(.*)\// && -e "$1/../ffmpeg" ? "$1/../ffmpeg" :
"ffmpeg";
my %channel_label_to_descr;
my %layout_to_channels;
{
open my $stderr, ">&STDERR";
open STDERR, ">", "/dev/null";
open my $f, "-|", $ffmpeg, "-layouts" or die "$ffmpeg: $!\n";
open STDERR, ">&", $stderr;
while (<$f>) {
chomp;
next if /^NAME/ or /:$/ or /^$/; # skip headings
my ($name, $descr) = split " ", $_, 2;
next unless $descr;
if ($descr =~ /^[[:upper:]]+(?:\+[[:upper:]]+)*$/) {
$layout_to_channels{$name} = [ split /\+/, $descr ];
} else {
$channel_label_to_descr{$name} = $descr;
}
}
}
my @channels = map { @{$layout_to_channels{$_} // [$_]} } split /\+/, $channels;
my $layout = join "+", @channels;
my $graph = "";
my $concat_in = "";
for my $i (0 .. $#channels) {
my $label = $channels[$i];
my $descr = $channel_label_to_descr{$label}
or die "Channel $label not found\n";
$graph .= "flite=text='${descr}', aformat=channel_layouts=mono, " .
"pan=${layout}:${label}=c0 [ch$i] ;\n";
$concat_in .= "[ch$i] ";
}
$graph .= "${concat_in}concat=v=0:a=1:n=" . scalar(@channels);
exec $ffmpeg, "-f", "lavfi", "-i", $graph, @out_options
or die "$ffmpeg: $!\n";