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python: Add python library wrapper

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Antoine Soulier
2024-01-04 14:12:54 -08:00
parent 10999c6c58
commit 8e0bd81fe4
9 changed files with 905 additions and 170 deletions
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19
README.md
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@@ -17,6 +17,7 @@ The directory layout is as follows :
- include: Library interface
- src: Source files
- tools: Standalone encoder/decoder tools
- python: Python wrapper
- test: Unit testing framework
- fuzz: Roundtrip fuzz testing harness
- build: Building outputs
@@ -62,7 +63,7 @@ Compiled library will be found in `bin` directory.
## Tools
Tools can be all compiled, while involking `make` as follows :
Tools can be all compiled, while invoking `make` as follows :
```sh
$ make tools
@@ -138,6 +139,7 @@ The conformance reports can be found [here](conformance/README.md)
The codec was [_here_](https://hydrogenaud.io/index.php/topic,122575.0.html)
subjectively evaluated in a blind listening test.
## Meson build system
Meson build system is also available to build and install lc3 codec in Linux
@@ -148,3 +150,18 @@ $ meson build
$ cd build && meson install
```
## Python wrapper
A python wrapper, installed as follows, is available in the `python` directory.
```sh
$ python3 -m pip install ./python
```
Decoding and encoding tools are provided in `python/tools`, like C tools,
you can easly test encoding / decoding loop with :
```sh
$ python3 ./python/tools/encoder.py <in.wav> --bitrate <bitrate> | \
python3 ./python/tools/decoder.py > <out.wav>
```

202
python/LICENSE Normal file
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@@ -0,0 +1,202 @@
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393
python/lc3.py Normal file
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@@ -0,0 +1,393 @@
#
# Copyright 2024 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import array
import ctypes
import enum
from ctypes import c_bool, c_byte, c_int, c_uint, c_size_t, c_void_p
from ctypes.util import find_library
class _Base:
def __init__(self, frame_duration, samplerate, nchannels, **kwargs):
self.hrmode = False
self.dt_us = int(frame_duration * 1000)
self.sr_hz = int(samplerate)
self.sr_pcm_hz = self.sr_hz
self.nchannels = nchannels
libpath = None
for k in kwargs.keys():
if k == 'hrmode':
self.hrmode = bool(kwargs[k])
elif k == 'pcm_samplerate':
self.sr_pcm_hz = int(kwargs[k])
elif k == 'libpath':
libpath = kwargs[k]
else:
raise ValueError("Invalid keyword argument: " + k)
if self.dt_us not in [2500, 5000, 7500, 10000]:
raise ValueError(
"Invalid frame duration: %.1f ms" % frame_duration)
allowed_samplerate = [8000, 16000, 24000, 32000, 48000] \
if not self.hrmode else [48000, 96000]
if self.sr_hz not in allowed_samplerate:
raise ValueError("Invalid sample rate: %d Hz" % samplerate)
if libpath is None:
libpath = find_library("lc3")
if not libpath:
raise Exception("LC3 library not found")
lib = ctypes.cdll.LoadLibrary(libpath)
try:
lib.lc3_hr_frame_samples \
and lib.lc3_hr_frame_block_bytes \
and lib.lc3_hr_resolve_bitrate \
and lib.lc3_hr_delay_samples
except AttributeError:
if self.hrmode:
raise Exception('High-Resolution interface not available')
lib.lc3_hr_frame_samples = \
lambda hrmode, dt_us, sr_hz: \
lib.lc3_frame_samples(dt_us, sr_hz)
lib.lc3_hr_frame_block_bytes = \
lambda hrmode, dt_us, sr_hz, nchannels, bitrate: \
nchannels * lib.lc3_frame_bytes(dt_us, bitrate // 2)
lib.lc3_hr_resolve_bitrate = \
lambda hrmode, dt_us, sr_hz, nbytes: \
lib.lc3_resolve_bitrate(dt_us, nbytes)
lib.lc3_hr_delay_samples = \
lambda hrmode, dt_us, sr_hz: \
lib.lc3_delay_samples(dt_us, sr_hz)
lib.lc3_hr_frame_samples.argtypes = [c_bool, c_int, c_int]
lib.lc3_hr_frame_block_bytes.argtypes = \
[c_bool, c_int, c_int, c_int, c_int]
lib.lc3_hr_resolve_bitrate.argtypes = [c_bool, c_int, c_int, c_int]
lib.lc3_hr_delay_samples.argtypes = [c_bool, c_int, c_int]
self.lib = lib
libc = ctypes.cdll.LoadLibrary(find_library("c"))
self.malloc = libc.malloc
self.malloc.argtypes = [c_size_t]
self.malloc.restype = c_void_p
self.free = libc.free
self.free.argtypes = [c_void_p]
def get_frame_samples(self):
"""
Returns the number of PCM samples in an LC3 frame
"""
ret = self.lib.lc3_hr_frame_samples(
self.hrmode, self.dt_us, self.sr_pcm_hz)
if ret < 0:
raise ValueError("Bad parameters")
return ret
def get_frame_bytes(self, bitrate):
"""
Returns the size of LC3 frame blocks, from bitrate in bit per seconds.
A target `bitrate` equals 0 or `INT32_MAX` returns respectively
the minimum and maximum allowed size.
"""
ret = self.lib.lc3_hr_frame_block_bytes(
self.hrmode, self.dt_us, self.sr_hz, self.nchannels, bitrate)
if ret < 0:
raise ValueError("Bad parameters")
return ret
def resolve_bitrate(self, nbytes):
"""
Returns the bitrate in bits per seconds, from the size of LC3 frames.
"""
ret = self.lib.lc3_hr_resolve_bitrate(
self.hrmode, self.dt_us, self.sr_hz, nbytes)
if ret < 0:
raise ValueError("Bad parameters")
return ret
def get_delay_samples(self):
"""
Returns the algorithmic delay, as a number of samples.
"""
ret = self.lib.lc3_hr_delay_samples(
self.hrmode, self.dt_us, self.sr_pcm_hz)
if ret < 0:
raise ValueError("Bad parameters")
return ret
@staticmethod
def _resolve_pcm_format(bitdepth):
PCM_FORMAT_S16 = 0
PCM_FORMAT_S24 = 1
PCM_FORMAT_S24_3LE = 2
PCM_FORMAT_FLOAT = 3
match bitdepth:
case 16: return (PCM_FORMAT_S16, ctypes.c_int16)
case 24: return (PCM_FORMAT_S24_3LE, 3 * ctypes.c_byte)
case None: return (PCM_FORMAT_FLOAT, ctypes.c_float)
case _: raise ValueError("Could not interpret PCM bitdepth")
class Encoder(_Base):
"""
LC3 Encoder wrapper
The `frame_duration` expressed in milliseconds is any of 2.5, 5.0, 7.5
or 10.0. The `samplerate`, in Hertz, is any of 8000, 16000, 24000, 32000
or 48000, unless High-Resolution mode is enabled. In High-Resolution mode,
the `samplerate` is 48000 or 96000.
By default, one channel is processed. When `nchannels` is greater than one,
the PCM input stream is read interleaved and consecutives LC3 frames are
output, for each channel.
Keyword arguments:
hrmode : Enable High-Resolution mode, default is `False`.
sr_pcm_hz : Input PCM samplerate, enable downsampling of input.
libpath : LC3 library path and name
"""
class c_encoder_t(c_void_p):
pass
def __init__(self, frame_duration, samplerate, nchannels=1, **kwargs):
super().__init__(frame_duration, samplerate, nchannels, **kwargs)
lib = self.lib
try:
lib.lc3_hr_encoder_size \
and lib.lc3_hr_setup_encoder
except AttributeError:
assert not self.hrmode
lib.lc3_hr_encoder_size = \
lambda hrmode, dt_us, sr_hz: \
lib.lc3_encoder_size(dt_us, sr_hz)
lib.lc3_hr_setup_encoder = \
lambda hrmode, dt_us, sr_hz, sr_pcm_hz, mem: \
lib.lc3_setup_encoder(dt_us, sr_hz, sr_pcm_hz, mem)
lib.lc3_hr_encoder_size.argtypes = [c_bool, c_int, c_int]
lib.lc3_hr_encoder_size.restype = c_uint
lib.lc3_hr_setup_encoder.argtypes = \
[c_bool, c_int, c_int, c_int, c_void_p]
lib.lc3_hr_setup_encoder.restype = self.c_encoder_t
lib.lc3_encode.argtypes = \
[self.c_encoder_t, c_int, c_void_p, c_int, c_int, c_void_p]
def new_encoder(): return lib.lc3_hr_setup_encoder(
self.hrmode, self.dt_us, self.sr_hz, self.sr_pcm_hz,
self.malloc(lib.lc3_hr_encoder_size(
self.hrmode, self.dt_us, self.sr_pcm_hz)))
self.__encoders = [new_encoder() for i in range(nchannels)]
def __del__(self):
try:
(self.free(encoder) for encoder in self.__encoders)
finally:
return
def encode(self, pcm, nbytes, bitdepth=None):
"""
Encode LC3 frame(s), for each channel.
The `pcm` input is given in two ways. When no `bitdepth` is defined,
it's a vector of floating point values from -1 to 1, coding the sample
levels. When `bitdepth` is defined, `pcm` is interpreted as a byte-like
object, each sample coded on `bitdepth` bits (16 or 24).
The machine endianness, or little endian, is used for 16 or 24 bits
width, respectively.
In both cases, the `pcm` vector data is padded with zeros when
its length is less than the required input samples for the encoder.
Channels concatenation of encoded LC3 frames, of `nbytes`, is returned.
"""
nchannels = self.nchannels
frame_samples = self.get_frame_samples()
(pcm_fmt, pcm_t) = self._resolve_pcm_format(bitdepth)
pcm_len = nchannels * frame_samples
if bitdepth is None:
pcm_buffer = array.array('f', pcm)
# Invert test to catch NaN
if not abs(sum(pcm)) / frame_samples < 2:
raise ValueError("Out of range PCM input")
padding = max(pcm_len - frame_samples, 0)
pcm_buffer.extend(array.array('f', [0] * padding))
else:
padding = max(pcm_len * ctypes.sizeof(pcm_t) - len(pcm), 0)
pcm_buffer = bytearray(pcm) + bytearray(padding)
data_buffer = (c_byte * nbytes)()
data_offset = 0
for (ich, encoder) in enumerate(self.__encoders):
pcm_offset = ich * ctypes.sizeof(pcm_t)
pcm = (pcm_t * (pcm_len - ich)).from_buffer(pcm_buffer, pcm_offset)
data_size = nbytes // nchannels + int(ich < nbytes % nchannels)
data = (c_byte * data_size).from_buffer(data_buffer, data_offset)
data_offset += data_size
ret = self.lib.lc3_encode(
encoder, pcm_fmt, pcm, nchannels, len(data), data)
if ret < 0:
raise ValueError("Bad parameters")
return bytes(data_buffer)
class Decoder(_Base):
"""
LC3 Decoder wrapper
The `frame_duration` expressed in milliseconds is any of 2.5, 5.0, 7.5
or 10.0. The `samplerate`, in Hertz, is any of 8000, 16000, 24000, 32000
or 48000, unless High-Resolution mode is enabled. In High-Resolution
mode, the `samplerate` is 48000 or 96000.
By default, one channel is processed. When `nchannels` is greater than one,
the PCM input stream is read interleaved and consecutives LC3 frames are
output, for each channel.
Keyword arguments:
hrmode : Enable High-Resolution mode, default is `False`.
sr_pcm_hz : Output PCM samplerate, enable upsampling of output.
libpath : LC3 library path and name
"""
class c_decoder_t(c_void_p):
pass
def __init__(self, frame_duration, samplerate, nchannels=1, **kwargs):
super().__init__(frame_duration, samplerate, nchannels, **kwargs)
lib = self.lib
try:
lib.lc3_hr_decoder_size \
and lib.lc3_hr_setup_decoder
except AttributeError:
assert not self.hrmode
lib.lc3_hr_decoder_size = \
lambda hrmode, dt_us, sr_hz: \
lib.lc3_decoder_size(dt_us, sr_hz)
lib.lc3_hr_setup_decoder = \
lambda hrmode, dt_us, sr_hz, sr_pcm_hz, mem: \
lib.lc3_setup_decoder(dt_us, sr_hz, sr_pcm_hz, mem)
lib.lc3_hr_decoder_size.argtypes = [c_bool, c_int, c_int]
lib.lc3_hr_decoder_size.restype = c_uint
lib.lc3_hr_setup_decoder.argtypes = \
[c_bool, c_int, c_int, c_int, c_void_p]
lib.lc3_hr_setup_decoder.restype = self.c_decoder_t
lib.lc3_decode.argtypes = \
[self.c_decoder_t, c_void_p, c_int, c_int, c_void_p, c_int]
def new_decoder(): return lib.lc3_hr_setup_decoder(
self.hrmode, self.dt_us, self.sr_hz, self.sr_pcm_hz,
self.malloc(lib.lc3_hr_decoder_size(
self.hrmode, self.dt_us, self.sr_pcm_hz)))
self.__decoders = [new_decoder() for i in range(nchannels)]
def __del__(self):
try:
(self.free(decoder) for decoder in self.__decoders)
finally:
return
def decode(self, data, bitdepth=None):
"""
Decode an LC3 frame
The input `data` is the channels concatenation of LC3 frames in a
byte-like object. Interleaved PCM samples are returned according to
the `bitdepth` indication.
When no `bitdepth` is defined, it's a vector of floating point values
from -1 to 1, coding the sample levels. When `bitdepth` is defined,
it returns a byte array, each sample coded on `bitdepth` bits.
The machine endianness, or little endian, is used for 16 or 24 bits
width, respectively.
"""
nchannels = self.nchannels
frame_samples = self.get_frame_samples()
(pcm_fmt, pcm_t) = self._resolve_pcm_format(bitdepth)
pcm_len = nchannels * self.get_frame_samples()
pcm_buffer = (pcm_t * pcm_len)()
data_buffer = bytearray(data)
data_offset = 0
for (ich, decoder) in enumerate(self.__decoders):
pcm_offset = ich * ctypes.sizeof(pcm_t)
pcm = (pcm_t * (pcm_len - ich)).from_buffer(pcm_buffer, pcm_offset)
data_size = len(data_buffer) // nchannels + \
int(ich < len(data_buffer) % nchannels)
data = (c_byte * data_size).from_buffer(data_buffer, data_offset)
data_offset += data_size
ret = self.lib.lc3_decode(
decoder, data, len(data), pcm_fmt, pcm, self.nchannels)
if ret < 0:
raise ValueError("Bad parameters")
return array.array('f', pcm_buffer) \
if bitdepth is None else bytes(pcm_buffer)

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python/pyproject.toml Normal file
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[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"
[project]
name = "lc3"
version = "0.0.1"
license = "Apache-2.0"
authors = [
{ name="Antoine Soulier", email="asoulier@google.com" },
]
description = "LC3 Codec library wrapper"
requires-python = ">=3.10"
[project.urls]
Homepage = "https://github.com/google/liblc3"

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python/tools/decoder.py Executable file
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#!/usr/bin/env python3
#
# Copyright 2024 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import argparse
import lc3
import struct
import sys
import wave
parser = argparse.ArgumentParser(description='LC3 Decoder')
parser.add_argument(
'lc3_file', nargs='?',
help='Input bitstream file, default is stdin',
type=argparse.FileType('rb'), default=sys.stdin.buffer)
parser.add_argument(
'wav_file', nargs='?',
help='Output wave file, default is stdout',
type=argparse.FileType('wb'), default=sys.stdout.buffer)
parser.add_argument(
'--bitdepth',
help='Output bitdepth, default is 16 bits',
type=int, choices=[16, 24], default=16)
parser.add_argument(
'--libpath', help='LC3 Library path')
args = parser.parse_args()
# --- LC3 File input ---
f_lc3 = args.lc3_file
header = struct.unpack('=HHHHHHHI', f_lc3.read(18))
if header[0] != 0xcc1c:
raise ValueError('Invalid bitstream file')
samplerate = header[2] * 100
nchannels = header[4]
frame_duration = header[5] / 100
stream_length = header[7]
# --- Setup output ---
bitdepth = args.bitdepth
pcm_size = nchannels * (bitdepth // 8)
f_wav = args.wav_file
wavfile = wave.open(f_wav)
wavfile.setnchannels(nchannels)
wavfile.setsampwidth(bitdepth // 8)
wavfile.setframerate(samplerate)
wavfile.setnframes(stream_length)
# --- Setup decoder ---
dec = lc3.Decoder(
frame_duration, samplerate, nchannels, libpath=args.libpath)
frame_length = dec.get_frame_samples()
encoded_length = stream_length + dec.get_delay_samples()
# --- Decoding loop ---
for i in range(0, encoded_length, frame_length):
lc3_frame_size = struct.unpack('=H', f_lc3.read(2))[0]
pcm = dec.decode(f_lc3.read(lc3_frame_size), bitdepth=bitdepth)
pcm = pcm[max(encoded_length - stream_length - i, 0) * pcm_size:
min(encoded_length - i, frame_length) * pcm_size]
wavfile.writeframesraw(pcm)
# --- Cleanup ---
wavfile.close()
for f in (f_lc3, f_wav):
if f is not sys.stdout.buffer:
f.close()

88
python/tools/encoder.py Executable file
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@@ -0,0 +1,88 @@
#!/usr/bin/env python3
#
# Copyright 2024 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import argparse
import lc3
import struct
import sys
import wave
parser = argparse.ArgumentParser(description='LC3 Encoder')
parser.add_argument(
'wav_file', nargs='?',
help='Input wave file, default is stdin',
type=argparse.FileType('rb'), default=sys.stdin.buffer)
parser.add_argument(
'lc3_file', nargs='?',
help='Output bitstream file, default is stdout',
type=argparse.FileType('wb'), default=sys.stdout.buffer)
parser.add_argument(
'--bitrate', help='Bitrate in bps', type=int, required=True)
parser.add_argument(
'--frame_duration', help='Frame duration in ms', type=float, default=10)
parser.add_argument(
'--libpath', help='LC3 Library path')
args = parser.parse_args()
# --- WAV File input ---
f_wav = args.wav_file
wavfile = wave.open(f_wav, 'rb')
samplerate = wavfile.getframerate()
nchannels = wavfile.getnchannels()
bitdepth = wavfile.getsampwidth() * 8
stream_length = wavfile.getnframes()
# --- Setup encoder ---
enc = lc3.Encoder(
args.frame_duration, samplerate, nchannels, libpath=args.libpath)
frame_size = enc.get_frame_bytes(args.bitrate)
frame_length = enc.get_frame_samples()
bitrate = enc.resolve_bitrate(frame_size)
# --- Setup output ---
f_lc3 = args.lc3_file
f_lc3.write(struct.pack(
'=HHHHHHHI', 0xcc1c, 18,
samplerate // 100, bitrate // 100, nchannels,
int(args.frame_duration * 100), 0, stream_length))
# --- Encoding loop ---
for i in range(0, stream_length, frame_length):
f_lc3.write(struct.pack('=H', frame_size))
pcm = wavfile.readframes(frame_length)
f_lc3.write(enc.encode(pcm, frame_size, bitdepth=bitdepth))
# --- Cleanup ---
wavfile.close()
for f in (f_wav, f_lc3):
if f is not sys.stdout.buffer:
f.close()

92
python/tools/specgram.py Executable file
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@@ -0,0 +1,92 @@
#!/usr/bin/env python3
#
# Copyright 2024 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import argparse
import lc3
import matplotlib
import matplotlib.pyplot as plt
import numpy as np
import scipy.signal as signal
matplotlib.use('QtAgg')
parser = argparse.ArgumentParser(description='LC3 Encoder')
parser.add_argument(
'--frame_duration', help='Frame duration (ms)', type=float, default=10)
parser.add_argument(
'--sample_rate', help='Sampling frequency (Hz)', type=float, default=48000)
parser.add_argument(
'--hrmode', help='Enable high-resolution mode', action='store_true')
parser.add_argument(
'--bitrate', help='Bitrate (bps)', type=int, default=96000)
parser.add_argument(
'--libpath', help='LC3 Library path')
args = parser.parse_args()
# --- Setup encoder + decoder ---
fs = args.sample_rate
enc = lc3.Encoder(
args.frame_duration, fs, hrmode=args.hrmode, libpath=args.libpath)
dec = lc3.Decoder(
args.frame_duration, fs, hrmode=args.hrmode, libpath=args.libpath)
frame_len = enc.get_frame_samples()
delay_len = enc.get_delay_samples()
# --- Generate 10 seconds chirp ---
n = 10 * int(fs)
t = np.arange(n - (n % frame_len)) / fs
s = signal.chirp(t, f0=10, f1=fs/2, t1=t[-1], phi=-90, method='linear')
# --- Encoding / decoding loop ---
frame_size = enc.get_frame_bytes(args.bitrate)
bitrate = enc.resolve_bitrate(frame_size)
y = np.empty(len(s) + frame_len)
for i in range(0, len(s), frame_len):
y[i:i+frame_len] = dec.decode(enc.encode(s[i:i+frame_len], frame_size))
y[len(s):] = dec.decode(enc.encode(np.zeros(frame_len), frame_size))
y = y[delay_len:len(s)+delay_len]
# --- Plot spectrograms ---
fig, (ax1, ax2) = plt.subplots(nrows=2, sharex=True)
NFFT = 512
for (ax, s) in [(ax1, s), (ax2, y)]:
ax.specgram(s, Fs=fs, NFFT=NFFT, pad_to=4*NFFT, noverlap=NFFT//2,
vmin=-160, vmax=0)
ax1.set_title('Input signal')
ax1.set_ylabel('Frequency (Hz)')
ax2.set_title(('Processed signal (%.1f kbps)' % (bitrate/1000)))
ax2.set_ylabel('Frequency (Hz)')
plt.show()

81
test/decoder.py Executable file → Normal file
View File

@@ -1,4 +1,3 @@
#!/usr/bin/env python3
#
# Copyright 2022 Google LLC
#
@@ -27,8 +26,6 @@ import tables as T, appendix_c as C
import mdct, energy, bwdet, sns, tns, spec, ltpf
import bitstream
### ------------------------------------------------------------------------ ###
class Decoder:
def __init__(self, dt_ms, sr_hz):
@@ -96,8 +93,6 @@ class Decoder:
return x
### ------------------------------------------------------------------------ ###
def check_appendix_c(dt):
i0 = dt - T.DT_7M5
@@ -120,79 +115,3 @@ def check():
ok = ok and check_appendix_c(dt)
return ok
### ------------------------------------------------------------------------ ###
if __name__ == "__main__":
parser = argparse.ArgumentParser(description='LC3 Decoder Test Framework')
parser.add_argument('lc3_file',
help='Input bitstream file', type=argparse.FileType('r'))
parser.add_argument('--pyout',
help='Python output file', type=argparse.FileType('w'))
parser.add_argument('--cout',
help='C output file', type=argparse.FileType('w'))
args = parser.parse_args()
### File Header ###
f_lc3 = open(args.lc3_file.name, 'rb')
header = struct.unpack('=HHHHHHHI', f_lc3.read(18))
if header[0] != 0xcc1c:
raise ValueError('Invalid bitstream file')
if header[4] != 1:
raise ValueError('Unsupported number of channels')
sr_hz = header[2] * 100
bitrate = header[3] * 100
nchannels = header[4]
dt_ms = header[5] / 100
f_lc3.seek(header[1])
### Setup ###
dec = Decoder(dt_ms, sr_hz)
dec_c = lc3.setup_decoder(int(dt_ms * 1000), sr_hz)
pcm_c = np.empty(0).astype(np.int16)
pcm_py = np.empty(0).astype(np.int16)
### Decoding loop ###
nframes = 0
while True:
data = f_lc3.read(2)
if len(data) != 2:
break
(frame_nbytes,) = struct.unpack('=H', data)
print('Decoding frame %d' % nframes, end='\r')
data = f_lc3.read(frame_nbytes)
x = dec.run(data)
pcm_py = np.append(pcm_py,
np.clip(np.round(x), -32768, 32767).astype(np.int16))
x_c = lc3.decode(dec_c, data)
pcm_c = np.append(pcm_c, x_c)
nframes += 1
print('done ! %16s' % '')
### Terminate ###
if args.pyout:
wavfile.write(args.pyout.name, sr_hz, pcm_py)
if args.cout:
wavfile.write(args.cout.name, sr_hz, pcm_c)
### ------------------------------------------------------------------------ ###

88
test/encoder.py Executable file → Normal file
View File

@@ -1,4 +1,3 @@
#!/usr/bin/env python3
#
# Copyright 2022 Google LLC
#
@@ -28,8 +27,6 @@ import attdet, ltpf
import mdct, energy, bwdet, sns, tns, spec
import bitstream
### ------------------------------------------------------------------------ ###
class Encoder:
def __init__(self, dt_ms, sr_hz):
@@ -104,8 +101,6 @@ class Encoder:
return data
### ------------------------------------------------------------------------ ###
def check_appendix_c(dt):
i0 = dt - T.DT_7M5
@@ -128,86 +123,3 @@ def check():
ok = ok and check_appendix_c(dt)
return ok
### ------------------------------------------------------------------------ ###
def dump(data):
for i in range(0, len(data), 20):
print(''.join('{:02x} '.format(x)
for x in data[i:min(i+20, len(data))] ))
if __name__ == "__main__":
parser = argparse.ArgumentParser(description='LC3 Encoder Test Framework')
parser.add_argument('wav_file',
help='Input wave file', type=argparse.FileType('r'))
parser.add_argument('--bitrate',
help='Bitrate in bps', type=int, required=True)
parser.add_argument('--dt',
help='Frame duration in ms', type=float, default=10)
parser.add_argument('--pyout',
help='Python output file', type=argparse.FileType('w'))
parser.add_argument('--cout',
help='C output file', type=argparse.FileType('w'))
args = parser.parse_args()
if args.bitrate < 16000 or args.bitrate > 320000:
raise ValueError('Invalid bitate %d bps' % args.bitrate)
if args.dt not in (7.5, 10):
raise ValueError('Invalid frame duration %.1f ms' % args.dt)
(sr_hz, pcm) = wavfile.read(args.wav_file.name)
if sr_hz not in (8000, 16000, 24000, 320000, 48000):
raise ValueError('Unsupported input samplerate: %d' % sr_hz)
if pcm.ndim != 1:
raise ValueError('Only single channel wav file supported')
### Setup ###
enc = Encoder(args.dt, sr_hz)
enc_c = lc3.setup_encoder(int(args.dt * 1000), sr_hz)
frame_samples = int((args.dt * sr_hz) / 1000)
frame_nbytes = int((args.bitrate * args.dt) / (1000 * 8))
### File Header ###
f_py = open(args.pyout.name, 'wb') if args.pyout else None
f_c = open(args.cout.name , 'wb') if args.cout else None
header = struct.pack('=HHHHHHHI', 0xcc1c, 18,
sr_hz // 100, args.bitrate // 100, 1, int(args.dt * 100), 0, len(pcm))
for f in (f_py, f_c):
if f: f.write(header)
### Encoding loop ###
if len(pcm) % frame_samples > 0:
pcm = np.append(pcm, np.zeros(frame_samples - (len(pcm) % frame_samples)))
for i in range(0, len(pcm), frame_samples):
print('Encoding frame %d' % (i // frame_samples), end='\r')
frame_pcm = pcm[i:i+frame_samples]
data = enc.run(frame_pcm, frame_nbytes)
data_c = lc3.encode(enc_c, frame_pcm, frame_nbytes)
for f in (f_py, f_c):
if f: f.write(struct.pack('=H', frame_nbytes))
if f_py: f_py.write(data)
if f_c: f_c.write(data_c)
print('done ! %16s' % '')
### Terminate ###
for f in (f_py, f_c):
if f: f.close()
### ------------------------------------------------------------------------ ###