mirror of
https://github.com/markqvist/Sideband.git
synced 2024-10-01 03:15:37 -04:00
142 lines
4.9 KiB
Python
142 lines
4.9 KiB
Python
import ctypes
|
|
from itertools import chain
|
|
|
|
from . import flac
|
|
from .pyogg_error import PyOggError
|
|
|
|
def _to_char_p(string):
|
|
try:
|
|
return ctypes.c_char_p(string.encode("utf-8"))
|
|
except:
|
|
return ctypes.c_char_p(string)
|
|
|
|
def _resize_array(array, new_size):
|
|
return (array._type_*new_size).from_address(ctypes.addressof(array))
|
|
|
|
|
|
class FlacFileStream:
|
|
def write_callback(self,decoder, frame, buffer, client_data):
|
|
multi_channel_buf = _resize_array(buffer.contents, self.channels)
|
|
arr_size = frame.contents.header.blocksize
|
|
if frame.contents.header.channels >= 2:
|
|
arrays = []
|
|
for i in range(frame.contents.header.channels):
|
|
arr = ctypes.cast(multi_channel_buf[i], ctypes.POINTER(flac.FLAC__int32*arr_size)).contents
|
|
arrays.append(arr[:])
|
|
|
|
arr = list(chain.from_iterable(zip(*arrays)))
|
|
|
|
self.buffer = (flac.FLAC__int16*len(arr))(*arr)
|
|
self.bytes_written = len(arr) * 2
|
|
|
|
else:
|
|
arr = ctypes.cast(multi_channel_buf[0], ctypes.POINTER(flac.FLAC__int32*arr_size)).contents
|
|
self.buffer = (flac.FLAC__int16*len(arr))(*arr[:])
|
|
self.bytes_written = arr_size * 2
|
|
return 0
|
|
|
|
def metadata_callback(self,decoder, metadata, client_data):
|
|
self.total_samples = metadata.contents.data.stream_info.total_samples
|
|
self.channels = metadata.contents.data.stream_info.channels
|
|
self.frequency = metadata.contents.data.stream_info.sample_rate
|
|
|
|
def error_callback(self,decoder, status, client_data):
|
|
raise PyOggError("An error occured during the process of decoding. Status enum: {}".format(flac.FLAC__StreamDecoderErrorStatusEnum[status]))
|
|
|
|
def __init__(self, path):
|
|
self.decoder = flac.FLAC__stream_decoder_new()
|
|
|
|
self.client_data = ctypes.c_void_p()
|
|
|
|
#: Number of channels in audio file.
|
|
self.channels = None
|
|
|
|
#: Number of samples per second (per channel). For
|
|
# example, 44100.
|
|
self.frequency = None
|
|
|
|
self.total_samples = None
|
|
|
|
self.buffer = None
|
|
|
|
self.bytes_written = None
|
|
|
|
self.write_callback_ = flac.FLAC__StreamDecoderWriteCallback(self.write_callback)
|
|
|
|
self.metadata_callback_ = flac.FLAC__StreamDecoderMetadataCallback(self.metadata_callback)
|
|
|
|
self.error_callback_ = flac.FLAC__StreamDecoderErrorCallback(self.error_callback)
|
|
|
|
init_status = flac.FLAC__stream_decoder_init_file(self.decoder,
|
|
_to_char_p(path),
|
|
self.write_callback_,
|
|
self.metadata_callback_,
|
|
self.error_callback_,
|
|
self.client_data)
|
|
|
|
if init_status: # error
|
|
raise PyOggError("An error occured when trying to open '{}': {}".format(path, flac.FLAC__StreamDecoderInitStatusEnum[init_status]))
|
|
|
|
metadata_status = (flac.FLAC__stream_decoder_process_until_end_of_metadata(self.decoder))
|
|
if not metadata_status: # error
|
|
raise PyOggError("An error occured when trying to decode the metadata of {}".format(path))
|
|
|
|
#: Bytes per sample
|
|
self.bytes_per_sample = 2
|
|
|
|
def get_buffer(self):
|
|
"""Returns the buffer.
|
|
|
|
Returns buffer (a bytes object) or None if all data has
|
|
been read from the file.
|
|
|
|
"""
|
|
# Attempt to read a single frame of audio
|
|
stream_status = (flac.FLAC__stream_decoder_process_single(self.decoder))
|
|
if not stream_status: # error
|
|
raise PyOggError("An error occured when trying to decode the audio stream of {}".format(path))
|
|
|
|
# Check if we encountered the end of the stream
|
|
if (flac.FLAC__stream_decoder_get_state(self.decoder) == 4): # end of stream
|
|
return None
|
|
|
|
buffer_as_bytes = bytes(self.buffer)
|
|
return buffer_as_bytes
|
|
|
|
def clean_up(self):
|
|
flac.FLAC__stream_decoder_finish(self.decoder)
|
|
|
|
def get_buffer_as_array(self):
|
|
"""Provides the buffer as a NumPy array.
|
|
|
|
Note that the underlying data type is 16-bit signed
|
|
integers.
|
|
|
|
Does not copy the underlying data, so the returned array
|
|
should either be processed or copied before the next call
|
|
to get_buffer() or get_buffer_as_array().
|
|
|
|
"""
|
|
import numpy # type: ignore
|
|
|
|
# Read the next samples from the stream
|
|
buf = self.get_buffer()
|
|
|
|
# Check if we've come to the end of the stream
|
|
if buf is None:
|
|
return None
|
|
|
|
# Convert the bytes buffer to a NumPy array
|
|
array = numpy.frombuffer(
|
|
buf,
|
|
dtype=numpy.int16
|
|
)
|
|
|
|
# Reshape the array
|
|
return array.reshape(
|
|
(len(buf)
|
|
// self.bytes_per_sample
|
|
// self.channels,
|
|
self.channels)
|
|
)
|