1 files changed, 19 insertions, 0 deletions

diff --git a/scripts/off2sec.pl b/scripts/off2sec.pl
new file mode 100755
index 0000000..0751be5
--- /dev/null
+++ b/scripts/off2sec.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/perl --
+# Given an offset of a byte number on disk,
+# this little script converts the given offset to the sector number
+# where the audio starts that is allocated by the given byte in the
+# usage table.
+# It is assumed that the drive usage table starts on offset 0xa00
+# (sector 5).
+# The blocks per cluster must be looked up in the boot record of the
+# drive before using this script; it varies based on drive capacity.
+my $blockspercluster=5;
+my $sectorsperblock=0x480;
+my $firstaudiosec=0x1397f6;
+my $usagetablestart=0xa00;
+my $recordingoffset=hex($ARGV[0]);
+my $bitsperbyte=8;
+my $startcluster=$recordingoffset-$usagetablestart;
+my $audiosec=$firstaudiosec+($sectorsperblock*$blockspercluster*$bitsperbyte*$startcluster);
+
+print sprintf("%x",$audiosec)."\n";