ref: 2c4de3dc497a89027aed78548436e64c3631499e
dir: /other/msu/encode_opus.py/
#!/usr/bin/env python3
import concurrent.futures
import opuslib
import struct
import samplerate # pip install samplerate
import numpy as np
# File format
# 4 byte: OPUZ
# 4 byte: VERSION = 0
# Foreach Repeat Entry {
# 4 byte: seek to file offset
# 4 byte: num pcm samples to play from here
# 2 byte: # samples to skip + flags
# }
def encode_to_msu_opus(msu_infile, bitrate = 128000):
raw_msu1 = bytearray(open(msu_infile, 'rb').read())
if raw_msu1[:4] != b'MSU1':
raise Exception('Expecting MSU1 file')
msu_repeat_pos, = struct.unpack_from('<I', raw_msu1, 4)
np_audio = np.frombuffer(raw_msu1[8:], dtype=np.int16)
np_audio = np.reshape(np_audio, (-1, 2)).astype(np.float32) * (1.0/32768.0)
assert np_audio.shape[1] == 2
#print('Song has %d samples in 44.1khz: %s' % (np_audio.shape[0], np_audio.dtype))
np_audio = samplerate.resample(np_audio, 48000 / 44100, 'sinc_best')
source_samples = np_audio.shape[0]
msu_repeat_pos = msu_repeat_pos * 48000 // 44100
#print('Song has %d samples in 48khz: %s' % (np_audio.shape[0], np_audio.dtype))
audio = bytearray(np_audio.tobytes())
FRAME_SIZE = 960
BYTES_PER_SAMPLE = 8
BYTES_PER_FRAME = FRAME_SIZE * BYTES_PER_SAMPLE
def create_encoder(bitrate):
enc = opuslib.Encoder(48000, 2, 'audio')
enc.vbr = True
enc.complexity = 10
enc.bitrate = bitrate
opuslib.api.encoder.encoder_ctl(enc.encoder_state, opuslib.api.ctl.ctl_set(11002), 1002) # force celt encoding
return enc
def pad_data_to_frame_size(audio, lookahead):
audio.extend(bytearray(lookahead * BYTES_PER_SAMPLE))
rest = len(audio) % BYTES_PER_FRAME
if rest:
audio.extend(bytearray(BYTES_PER_FRAME - rest))
enc = create_encoder(bitrate)
pad_data_to_frame_size(audio, enc.lookahead)
assert len(audio) % BYTES_PER_FRAME == 0
result = bytearray()
framelist = []
for i in range(len(audio)//BYTES_PER_FRAME):
l = enc.encode_float(bytes(audio[i*BYTES_PER_FRAME:i*BYTES_PER_FRAME+BYTES_PER_FRAME]), frame_size = FRAME_SIZE)
code = len(l)
if l[0] == 0xfc:
l = l[1:]
code = (code - 1) | 0x8000
framelist.append((i*FRAME_SIZE, len(result)))
result.extend(struct.pack('<H', code))
result.extend(l)
# print(len(l), '%.2x'%l[0])
return result, framelist, enc.lookahead, msu_repeat_pos, source_samples
def convert_to_opuz(filename, repeat):
print('Converting %s' % filename)
result, framelist, preskip, msu_repeat_pos, songlength = encode_to_msu_opus(filename, 128000)
# lookup what sample to seek to based on a sample nr
def lookup_sample(framelist, sample_nr):
last = None
for sample, fileoffs in framelist:
if sample_nr < sample:
break
last = sample, fileoffs
return last
def calc_play_ranges(xs):
r = []
for i, (start, end, repeat_from_here) in enumerate(xs):
frame = lookup_sample(framelist, start)
r.append((frame[1], end - start, preskip + start - frame[0], start, repeat_from_here))
return r
def serialize_header(xs):
r = b'OPUZ' + struct.pack('<I', 0)
offs = len(r) + len(xs) * 10
for i, (a, b, c, d, e) in enumerate(xs):
f = c | (0x4000 if e else 0x0) | (0x8000 if i == len(xs) - 1 else 0)
r += struct.pack('<IIH', a + offs, b, f)
return r
# lookup the frame that contains msu_repeat_pos
if repeat:
play_ranges = [(0, songlength, False), (msu_repeat_pos, songlength, True)]
else:
play_ranges = [(0, songlength, False)]
play_ranges = calc_play_ranges(play_ranges)
header = serialize_header(play_ranges)
if filename.endswith('.pcm'):
filename = filename[:-4]
open(filename + '.opuz', 'wb').write(header + result)
kMsuTracksWithRepeat = [
1,0,1,1,1,1,1,1,0,1,0,1,1,1,1,0,
1,1,1,0,1,1,1,1,1,1,1,1,1,0,1,1,
1,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,
]
def task(i):
convert_to_opuz(r"../../msu/ALttP-msu-Deluxe-%d.pcm" % i, i >= 48 or kMsuTracksWithRepeat[i])
with concurrent.futures.ThreadPoolExecutor() as executor:
results = [executor.submit(task, i) for i in range(1, 115)]
for future in concurrent.futures.as_completed(results):
result = future.result()