echnoest_remix_fun.py

###########################################################################
## Playing around with the awesome Echonest Remix API.
##
## http://code.google.com/p/echo-nest-remix/
##
## This is a script that will loop 4 beats from track 1 and mix them 
## behind track 2., also syncing the track tempos
##
## Change the variables below.
###########################################################################

import operator

from echonest import audio
from echonest.modify import Modify
from pyechonest import config

##################################################################################
# Variables

config.ECHO_NEST_API_KEY="XXXXXXXX"  # Put Your API Key Here

LOOP_SONG_PATH = "/Users/bsstoner/Music/Passion Pit/Manners/09 - Sleepyhead.mp3"
MAIN_SONG_PATH = "/Users/bsstoner/Music/05 O.N.E.mp3"

LOOP_OCTAVE = 0 # Set to +1 or -1 to raise/lower the octave of the loop track
LOOP_VOL_ADJUSTMENT = -3 # can make the loop louder/quieter 

OUTPUT_SONG_PATH = "/Users/bsstoner/Music/mashup.mp3"

#
##################################################################################

back_loop = audio.LocalAudioFile(LOOP_SONG_PATH)
song = audio.LocalAudioFile(MAIN_SONG_PATH)

# Shift the tempo so the two songs are aligned, save temp file and re open.
m = Modify()
ratio = song.analysis.tempo['value']/back_loop.analysis.tempo['value']
new_loop = m.shiftTempo(back_loop,ratio)
new_loop = m.shiftPitchOctaves(new_loop,LOOP_OCTAVE)
new_loop.encode("temposhift.mp3")
back_loop = audio.LocalAudioFile("temposhift.mp3")

connect = audio.AudioQuantumList()

loop_beats = back_loop.analysis.beats
song_beats = song.analysis.beats

iBeat = 0 # cycle 0 through 3
iVariation = 0 # Variation Offset, moves the loop sample forward
iVarCounter = 0 # Variation Counter, only moving the offset by 8, every 16 beats in the main track

softer = audio.LevelDB(LOOP_VOL_ADJUSTMENT) 

for b in song_beats:
    loop_beat = loop_beats[iBeat+iVariation]
    new_beat = audio.Simultaneous([b,softer(loop_beat)])     
    song_beats.insert(song_beats.index(b),new_beat) # Insert into the beat list
    song_beats.remove(b) # remove the old beat    
    
    if iBeat==3:
        # Every 4 beats, reseat the iBeat counter
        iBeat=0
        
        # Only increment variation counter if there's enough beats in the loop track
        if (iVarCounter==15):
            if (iVariation<24):
                iVariation+=8
            else:
                iVariation=0
            
            iVarCounter=0 # reset the counter
        # Increment Counters    
        iVarCounter+=1
    else:
        iBeat+=1 

[connect.append(b) for b in song_beats]        
connect.encode(OUTPUT_SONG_PATH)