prez/sound.py

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from base import rObject
import audioop
import struct
import re
import sys
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import os
from math import log2
__all__ = ["rSoundSample"]
# See: IIgs TechNote #76 Miscellaneous Resource Formats
# See: HCGS TechNote #3 Pitching Sampled Sounds
# HyperCard assumes a sample rate of 26.32 KHz (DOC rate w/ 32 oscillators)
# and a pitch of 261.63 Hz (Middle C, C4)
# See HyperCard IIgs Tech Note #3: Pitching Sampled Sounds
def relative_pitch(fS, fW = None):
# fW = frequency of sample
# fS = sampling rate
r = 0
if fW: r = (261.63 * fS) / (26320 * fW)
else: r = fS / 26320
offset = round(3072 * log2(r))
if (offset < -32767) or (offset > 32767):
raise Exception("Audio error: offset too big")
if offset < 0: offset = 0x8000 | abs(offset)
return offset
def pitch_to_hz(p):
if p == None: return 261.63
if type(p) in (int, float): return float(p)
if type(p) == str:
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m = re.match("^([A-Ga-g])([#b])?([0-8])$", p)
if not m: return None
note = m1[1].upper(); accidental = m[2]; octave = int(m[3])
a = "CxDxEFxGxAxB".index(note)-9
if accidental == "#": a += 1
if accidental == "b": a -= 1
f = 440.0 * (2 ** (a/12))
f *= 2 ** (octave-4)
return f
return None
def open_audio(file):
_, ext = os.path.splitext(os.path.basename(file))
ext = ext.lower()
# if ext in (".wav", ".wave"):
# import wave
# return wave.open(file, "rb"), 'little', 128
if ext in (".aiff", ".aifc", ".aif"):
import aifc
return aifc.open(file, "rb"), 'big', 'AIFF'
if ext in (".au", ".snd"):
import sunau
return sunau.open(file, "rb"), 'big', 'SUN'
# default
import wave
return wave.open(file, "rb"), 'little', 'WAVE'
class rSoundSample(rObject):
"""
filename: input file to read. format is .wav, .au, .aiff, or .aifc
pitch: audio pitch, if this is a note. specify hz (eg 261.63) or name (eg c4)
rate: down/upsample audio to this rate (eg 26320)
channel: stereo channel
Native samples are 26320 khz, c4 (261.63 hz)
"""
rName = "rSoundSample"
rType = 0x8024
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def __init__(self, filename, pitch=None, rate=None, channel=0, **kwargs):
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super().__init__(**kwargs)
new_rate = rate
freq = pitch_to_hz(pitch)
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if not freq: raise ValueError("Invalid pitch: {}".format(pitch))
# audio conversion
verbose = False
# if verbose: print("Input File: {}".format(filename))
rv = bytearray()
tr = b"\x01" + bytes(range(1,256)) # remap 0 -> 1
rv += struct.pack("<10x") # header filled in later
src, byteorder, fmt = open_audio(filename)
width = src.getsampwidth()
channels = src.getnchannels()
rate = src.getframerate()
bias = 128
swap = width > 1 and sys.byteorder != byteorder
if width == 1 and fmt == 'wave': bias = 0
if verbose:
print("Input: {} ch, {} Hz, {}-bit, {} ({} frames)".format(
channels,
rate,
width*8,
fmt,
src.getnframes()
))
if channels > 2:
raise Exception("{}: Too many channels ({})".format(filename, channels))
cookie = None
while True:
frames = src.readframes(32)
if not frames: break
if swap:
frames = audioop.byteswap(frames, width)
if channels > 1:
frames = audioop.tomono(frames, width, 0.5, 0.5)
if new_rate:
frames, cookie = audioop.ratecv(frames, width, 1, rate, new_rate, cookie)
if width != 1:
frames = audioop.lin2lin(frames, width, 1)
if bias:
frames = audioop.bias(frames, 1, bias)
frames = frames.translate(tr)
rv += frames
src.close()
# based on system 6 samples, pages rounds down....
# probably a bug.
pages = (len(rv)-10+255) >> 8
hz = new_rate or rate
rp = relative_pitch(hz, freq)
struct.pack_into("<HHHHH", rv, 0,
0, # format
pages, # wave size in pages
rp,
channel, # stereo
hz # hz
)
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self.data = bytes(rv)
self.pages = pages
self.channel = channel
self.relative_pitch = rp
self.sample_rate = hz
if verbose:
print("Output: 1 ch, {} Hz, 8-bit, rSoundSample ({} frames, {:.02f} Hz)".format(
hz, len(rv)-10, freq or 261.63))
print()
def __bytes__(self):
return self.data
def _rez_string(self):
return (
"\t0, /* format */\n"
"\t{}, /* size (pages) */\n"
"\t0x{:04x}, /* relative pitch */\n"
"\t0x{:04x}, /* stereo channel */\n"
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"\t{:d}, /* sample rate */\n"
"\t..."
).format(
self.pages,
self.relative_pitch,
self.channel,
self.sample_rate
)