aklaswad

AMXD file analysis

This document is a personal memo summarizing the results of my own analysis of amxd file format. It was originally written around the end of 2023. Please do not expect any correctness here. A parser is now publicly available at https://github.com/Ableton/maxdevtools/tree/main/maxdiff, so please refer to that for the correct specifications and further details.

---

I examined the AMXD file and found it to be an uncompressed format that combines the contents of multiple files. The overall structure resembles a simple chunk-based binary file, similar to RIFF. However, perhaps due to historical reasons, it contains two different chunk styles.

File structure overview

aklaswad

exponent setup from center value for live.dial

<pre><code>
----------begin_max5_patcher----------
2443.3oc6b07aiaqD+bVf8+ABibnaahi3WhRsGKdGemd8V2hEJNzwp0RxPRN
aBJd+uWQNTxRw1TLwTqyFzcQh7HIaM+FNeyw4u+3GtX1sEOJqlg9Yzuit3h+
t4LWnOm5LWzdhKlkk73h0IU5ab1hhrLYd8rqLWrV9Xs9B+1pzJzlj5EqjknM
kE2lb65mPqRpPInMxxkEkYI4Kj5KsVlgRpQqKxuGUmlIQaqjyQ+Oor6iMeaV
Z9ZYs9gh6c1hs0smNn8zo2o4fha+yqw3ntOCMyjle+WJkKpATRIz4AWgXDh9
PXn5.IXd.5Ozuo++G+f5XygqNcIxxxhLTQsRdPQOjrdair9zwWnM7wvBMvhm

aklaswad

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More;
use Data::ObjectDriver::Driver::DBI;
use Parallel::ForkManager;

sub main {
    # Init dbh and make sure it was connected by parent process
    my $driver = Data::ObjectDriver::Driver::DBI->new(

aklaswad

#!/usr/bin/env perl
use strict;
use warnings;
use Test::More tests => 10;
use Data::ObjectDriver::Driver::DBI;
use Parallel::ForkManager;

sub main {
    # Init dbh and make sure it was connected in parent process
    my $driver = Data::ObjectDriver::Driver::DBI->new(

aklaswad

1 // <<HACK;
/*                                                                                                                                          
HACK                                                                                                                                        

use strict;
use warnings;
use Plack::Runner;

my $js = do { local $/; <DATA> };
my $html = <<'HTML';

aklaswad

#!/usr/bin/env perl                                                                                                                         
1 // <<HACK;
/*                                                                                                                                          
HACK                                                                                                                                        

use strict;
use warnings;
use Plack::Runner;

my $js = do { local $/; <DATA> };

aklaswad

use strict;
use warnings;

# find the most greater value in range of less or equal to given target.
# returns the index of that value.
# array must be ascend sorted.
sub idx_of_max_in {
    my ( $array, $head, $tail, $target ) = @_;
    return $tail if $array->[$tail] <= $target;
    return $head if $array->[$head] == $target;

aklaswad

use strict;
use warnings;

my $PRICE_MAX = 1_000_000;
my $PRICE_MIN = 10;
my $ALGORITHM_SWITCH_THRESHOLD = 1000; # TODO: 適当に決めるな馬鹿

my @lines = split "\n", do { local $/; <> };
my ( $num_products, undef ) = split( " ", shift(@lines) );
my @prices = splice( @lines, 0, $num_products );

aklaswad

use strict;
use warnings;

my $PRICE_MAX = 1_000_000;

my @lines = split "\n", do { local $/; <> };
my ( $num_products, undef ) = split( " ", shift(@lines) );
my @prices = splice( @lines, 0, $num_products );

my @hist;

aklaswad

var async_task = function (msg, delay) {
  var dfd = $.Deferred();
  setTimeout( function () {
    if ( msg !== 'l' ) {
      dfd.resolve('resolved:' + msg);
    }
    else {
      dfd.reject('rejected:' + msg);
    }