quick and dirty x/y osciloscope for playing audio files such as https://www.youtube.com/watch?v=o4YyI6_y6kw

scope.py

"""
Usage:
    scope.py <input_file>
"""
from __future__ import division
import pygame
import audiotools
from docopt import docopt
import itertools
import time
import math
import subprocess

def frameiterator(pcm):
    while True:
        lst=pcm.read(pcm.sample_rate).to_float()
        for frame in lst:
            yield frame

FPS=60
PERSISTENCE=0.8
COLOR=(50,160,200)
BGCOLOR=(COLOR[0]*0.5,COLOR[1]*0.5,COLOR[2]*0.5)

framedelay=0
if __name__=="__main__":
    opt=docopt(__doc__)
    
    print "loading file"
    afid=audiotools.open(opt["<input_file>"])
    
    if afid.channels()!=2:
        print "expected 2 channels, got",afid.channels()
    
    print afid.sample_rate()/FPS,"samples per frame"
    samplesperframe=int(afid.sample_rate()/FPS)
    pcm=afid.to_pcm()
    
    it=frameiterator(pcm)
    
    print "creating window"
    
    pygame.init()
    W,H=480,480
    HW,HH=W//2,H//2
    maxdis=500
    screen=pygame.display.set_mode((W,H))
    buff=pygame.Surface((W,H))
    buff2=pygame.Surface((W,H))
    vignette=pygame.image.load("vignette.bmp").convert()
    screen.fill((0,0,0))
    buff2.fill((0,0,0))
    pygame.display.flip()
    clock=pygame.time.Clock()
    px,py=None,None
    
    print "starting audio"
    audio=subprocess.Popen(["mplayer","-slave","-quiet","-input","nodefault-bindings","-noconfig","all",opt["<input_file>"]],stdout=subprocess.PIPE,stdin=subprocess.PIPE)
    audio.stdin.write("pause\n")
    time.sleep(0.1)#Starting playback...
    buf=""
    while True:
        buf+=audio.stdout.read(1)
        print buf
        if buf.endswith("Starting playback...\n"):
            break
    print buf
    print "unpausing audio"
    audio.stdin.write("pause\n")
    print "starting visual"
    
    time_index=0
    frame_index=0
    while True:
        pygame.event.pump()
        buff2.fill((PERSISTENCE*255,PERSISTENCE*255,PERSISTENCE*255),special_flags=pygame.BLEND_MULT)
        #screen.fill((250,250,250),special_flags=pygame.BLEND_MULT)
        buff.lock()
        buff.fill((0,0,0))
        for i in range(samplesperframe):
            x=int(it.next()*HW+HW)
            y=int(it.next()*HH+HH)
            if px!=None:
                dis=(x-px)**2+(y-py)**2
                if dis>maxdis:
                    a=0
                elif dis==0:
                    a=1
                else:
                    a=(maxdis-dis)/maxdis
                    if a<0:
                        a=0
                if a>0:
                    w=int(5.5*a)
                    if w<1:
                        w=1
                    pygame.draw.line(buff,(int(COLOR[0]*a),int(COLOR[1]*a),int(COLOR[2]*a)),(x,y),(px,py),w)#special_flags=pygame.BLEND_ADD
            px,py=x,y
        buff.unlock()
        buff2.blit(buff,(0,0),special_flags=pygame.BLEND_ADD)
        screen.fill(COLOR)
        
        for y in range(H//10,H,H//10):
            pygame.draw.line(screen,BGCOLOR,(0,y),(W,y))
        
        for y in range(H//60,H,H//60):
            pygame.draw.line(screen,BGCOLOR,(HW-5,y),(HW+5,y))
        
        for x in range(W//10,W,W//10):
            pygame.draw.line(screen,BGCOLOR,(x,0),(x,H))
        
        for x in range(W//60,W,W//60):
            pygame.draw.line(screen,BGCOLOR,(x,HH-5),(x,HH+5))
            
        screen.blit(buff2,(0,0),special_flags=pygame.BLEND_ADD)
        screen.blit(vignette,(0,0),special_flags=pygame.BLEND_MULT)
        pygame.display.flip()
        clock.tick(FPS+1)#+1 to make it slowly catch up with audio if its behind
        time.sleep(framedelay)
        clock.tick()
        time_index+=1/FPS
        frame_index+=1
        if frame_index%FPS==FPS-1:
            #time_pos
            #print "getting skew"
            audio.stdin.write("get_time_pos\n")
            buf=""
            while len(buf)==0 or buf[-1]!="\n":
                buf+=audio.stdout.read(1)
            buf=buf.strip()
            #print buf
            rtime=float(buf.partition('=')[-1])
            diff=time_index-rtime
            #print "adjusting clock skew of",diff
            if diff>0:
                framedelay=diff/FPS
            else:
                framedelay=0