From 1b355552070c89490e116f8afaaf0520a1de6ff5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jure=20=C5=A0orn?= Date: Thu, 22 Aug 2019 17:18:47 +0200 Subject: [PATCH] Audio --- README.md | 39 ++++++++++++++++++++++++--------------- index.html | 36 ++++++++++++++++++++++-------------- 2 files changed, 46 insertions(+), 29 deletions(-) diff --git a/README.md b/README.md index 3568eb1..92b5f47 100644 --- a/README.md +++ b/README.md @@ -2662,23 +2662,32 @@ import wave, struct .setframerate() # Frames per second. ``` -### Read Frames from WAV File +### Read Float Frames from WAV File ```python def read_wav_file(filename): + def get_int(a_bytes): + an_int = int.from_bytes(a_bytes, 'little', signed=width!=1) + return an_int - 128 * (width == 1) with wave.open(filename, 'rb') as file: frames = file.readframes(file.getnframes()) - return [a[0] for a in struct.iter_unpack(''test.gif', frames, duration=# Sample size in bytes. <Wave_write>.setframerate(<int>) # Frames per second. -

Read Frames from WAV File

def read_wav_file(filename):
+
Read Float Frames from WAV File
def read_wav_file(filename):
+    def get_int(a_bytes):
+        an_int = int.from_bytes(a_bytes, 'little', signed=width!=1)
+        return an_int - 128 * (width == 1)
     with wave.open(filename, 'rb') as file:
         frames = file.readframes(file.getnframes())
-        return [a[0] for a in struct.iter_unpack('<h', frames)]
+        width  = file.getsampwidth()
+    chunks = (frames[i: i + width] for i in range(0, len(frames), width))
+    return [get_int(a) / pow(2, width * 8 - 1) for a in chunks]
 

 
-
Write Frames to WAV File
def write_to_wav_file(filename, frames_int, mono=True):
-    frames_short = (struct.pack('<h', a) for a in frames_int)
+
Write Float Frames to WAV File
def write_to_wav_file(filename, frames_float, nchannels=1, sampwidth=2, framerate=44100):
+    def get_bytes(a_float):
+        a_float = max(-1, min(1 - 2e-16, a_float))
+        a_float += sampwidth == 1
+        a_float *= pow(2, sampwidth * 8 - 1)
+        return int(a_float).to_bytes(sampwidth, 'little', signed=sampwidth!=1) 
     with wave.open(filename, 'wb') as file:
-        file.setnchannels(1 if mono else 2)
-        file.setsampwidth(2)
-        file.setframerate(44100)
-        file.writeframes(b''.join(frames_short))
+        file.setnchannels(nchannels)
+        file.setsampwidth(sampwidth)
+        file.setframerate(framerate)
+        file.writeframes(b''.join(get_bytes(a) for a in frames_float))
 

 
 
Examples
Saves a sine wave to a mono WAV file:
from math import pi, sin
 frames_f = (sin(i * 2 * pi * 440 / 44100) for i in range(100000))
-frames_i = (int(a * 30000) for a in frames_f)
-write_to_wav_file('test.wav', frames_i)
+write_to_wav_file('test.wav', frames_f)
 

 
 
-
Adds noise to a mono WAV file:
from random import randint
-add_noise = lambda value: max(-32768, min(32767, value + randint(-500, 500)))
-frames_i  = (add_noise(a) for a in read_wav_file('test.wav'))
-write_to_wav_file('test.wav', frames_i)
+
Adds noise to a mono WAV file:
from random import random
+add_noise = lambda value: max(-1, min(1, value + (random()-0.5)*0.03))
+frames_f  = (add_noise(a) for a in read_wav_file('test.wav'))
+write_to_wav_file('test.wav', frames_f)
 

 
 
#Synthesizer
Plays Popcorn by Gershon Kingsley:
# $ pip3 install simpleaudio