Ubuntu Podcast of Yesteryear Original Unit Reproduction Script

upyours.rb

# Usage: upyours.rb episode1.mp3 episode2.mp3 jingle.mp3 outputfile.mp3
# License: https://opensource.org/licenses/MIT
duration = `ffprobe -v 0 -show_entries format=duration -of compact=p=0:nk=1 #{ARGV[0]}`.to_f # Get the duration of the first file
fingerprint = `fpcalc #{ARGV[2]} -length 10 -raw`.lines[2].split('=')[1].split(',') # Get the fingetprint of the third file
$lt1000 = false # Set a flag
$discrepencies = Hash.new() # Store discrepencies for each clip
((duration.to_i*10-(90*10))..(duration.to_i*10)).each do | offset | # Scan through the last 90 seconds of the episode, in 1/10s intervals
    pos = (offset.to_f / 10) # Caluclate the starting position of the clip
    `ffmpeg -y -t 10 -ss #{pos} -i #{ARGV[0]} /tmp/testclip.mp3 > /dev/null 2>&1` # Get a 10 second clip from the starting position
    testprint = `fpcalc /tmp/testclip.mp3 -length 10 -raw`.lines[2].split('=')[1].split(',') # Get the fingerprint of the clip
    discrepency = 0
    fingerprint.zip(testprint).to_h.each_pair do | finger, test |
	# Compare the fingerprints by XORing each pair of numbers.  The more bits that match, the closer the fingerprints are.
	# Add up all the discrepencies (bits set to 1 after XOR)
	discrepency += (finger.to_i ^ test.to_i).to_s(2).count("1")
    end
    if (!$lt1000 && discrepency < 1000) then $lt1000 = true; end # < 1000 is a pretty good match, we're nearly at the clip.
    if ($lt1000 && discrepency > 1600) then break; end # We've gone past the clip, so stop scanning through.
    $discrepencies[pos] = discrepency # Store the discrepency against the start position, and try the next clip.
end
cliplength = $discrepencies.key($discrepencies.values.min) # We want a clip from the start of the file to the position of the closest match (lowest discrepency) found above.
`ffmpeg -y -t #{cliplength} -i #{ARGV[0]} /tmp/start.mp3
`ffmpeg -y -i "concat:/tmp/start.mp3|#{ARGV[1]}" -acodec copy #{ARGV[3]}` # Stick the clip onto the start of the second file.
File.delete('/tmp/start.mp3', '/tmp/testclip.mp3') # Delete the temporary files