mirror of
https://github.com/liberatedsystems/openCom-Companion.git
synced 2024-11-23 05:50:36 +01:00
408 lines
15 KiB
Python
408 lines
15 KiB
Python
|
import copy
|
||
|
|
import ctypes
|
||
|
|
from typing import Optional, ByteString, List, Tuple, Callable
|
||
|
|
import warnings
|
||
|
|
|
||
|
|
from . import opus
|
||
|
|
from .opus_encoder import OpusEncoder
|
||
|
|
from .pyogg_error import PyOggError
|
||
|
|
|
||
|
|
class OpusBufferedEncoder(OpusEncoder):
|
||
|
|
# TODO: This could be made more efficient. We don't need a
|
||
|
|
# deque. Instead, we need only sufficient PCM storage for one
|
||
|
|
# whole packet. We know the size of the packet thanks to
|
||
|
|
# set_frame_size().
|
||
|
|
|
||
|
|
def __init__(self) -> None:
|
||
|
|
super().__init__()
|
||
|
|
|
||
|
|
self._frame_size_ms: Optional[float] = None
|
||
|
|
self._frame_size_bytes: Optional[int] = None
|
||
|
|
|
||
|
|
# Buffer contains the bytes required for the next
|
||
|
|
# frame.
|
||
|
|
self._buffer: Optional[ctypes.Array] = None
|
||
|
|
|
||
|
|
# Location of the next free byte in the buffer
|
||
|
|
self._buffer_index = 0
|
||
|
|
|
||
|
|
|
||
|
|
def set_frame_size(self, frame_size: float) -> None:
|
||
|
|
""" Set the desired frame duration (in milliseconds).
|
||
|
|
|
||
|
|
Valid options are 2.5, 5, 10, 20, 40, or 60ms.
|
||
|
|
|
||
|
|
"""
|
||
|
|
|
||
|
|
# Ensure the frame size is valid. Compare frame size in
|
||
|
|
# units of 0.1ms to avoid floating point comparison
|
||
|
|
if int(frame_size*10) not in [25, 50, 100, 200, 400, 600]:
|
||
|
|
raise PyOggError(
|
||
|
|
"Frame size ({:f}) not one of ".format(frame_size)+
|
||
|
|
"the acceptable values"
|
||
|
|
)
|
||
|
|
|
||
|
|
self._frame_size_ms = frame_size
|
||
|
|
|
||
|
|
self._calc_frame_size()
|
||
|
|
|
||
|
|
|
||
|
|
def set_sampling_frequency(self, samples_per_second: int) -> None:
|
||
|
|
super().set_sampling_frequency(samples_per_second)
|
||
|
|
self._calc_frame_size()
|
||
|
|
|
||
|
|
|
||
|
|
def buffered_encode(self,
|
||
|
|
pcm_bytes: memoryview,
|
||
|
|
flush: bool = False,
|
||
|
|
callback: Callable[[memoryview,int,bool],None] = None
|
||
|
|
) -> List[Tuple[memoryview, int, bool]]:
|
||
|
|
"""Gets encoded packets and their number of samples.
|
||
|
|
|
||
|
|
This method returns a list, where each item in the list is
|
||
|
|
a tuple. The first item in the tuple is an Opus-encoded
|
||
|
|
frame stored as a bytes-object. The second item in the
|
||
|
|
tuple is the number of samples encoded (excluding
|
||
|
|
silence).
|
||
|
|
|
||
|
|
If `callback` is supplied then this method will instead
|
||
|
|
return an empty list but call the callback for every
|
||
|
|
Opus-encoded frame that would have been returned as a
|
||
|
|
list. This option has the desireable property of
|
||
|
|
eliminating the copying of the encoded packets, which is
|
||
|
|
required in order to form a list. The callback should
|
||
|
|
take two arguments, the encoded frame (a Python bytes
|
||
|
|
object) and the number of samples encoded per channel (an
|
||
|
|
int). The user must either process or copy the data as
|
||
|
|
the data may be overwritten once the callback terminates.
|
||
|
|
|
||
|
|
"""
|
||
|
|
# If there's no work to do return immediately
|
||
|
|
if len(pcm_bytes) == 0 and flush == False:
|
||
|
|
return [] # no work to do
|
||
|
|
|
||
|
|
# Sanity checks
|
||
|
|
if self._frame_size_ms is None:
|
||
|
|
raise PyOggError("Frame size must be set before encoding")
|
||
|
|
assert self._frame_size_bytes is not None
|
||
|
|
assert self._channels is not None
|
||
|
|
assert self._buffer is not None
|
||
|
|
assert self._buffer_index is not None
|
||
|
|
|
||
|
|
# Local variable initialisation
|
||
|
|
results = []
|
||
|
|
pcm_index = 0
|
||
|
|
pcm_len = len(pcm_bytes)
|
||
|
|
|
||
|
|
# 'Cast' memoryview of PCM to ctypes Array
|
||
|
|
Buffer = ctypes.c_ubyte * len(pcm_bytes)
|
||
|
|
try:
|
||
|
|
pcm_ctypes = Buffer.from_buffer(pcm_bytes)
|
||
|
|
except TypeError:
|
||
|
|
warnings.warn(
|
||
|
|
"Because PCM was read-only, an extra memory "+
|
||
|
|
"copy was required; consider storing PCM in "+
|
||
|
|
"writable memory (for example, bytearray "+
|
||
|
|
"rather than bytes)."
|
||
|
|
)
|
||
|
|
pcm_ctypes = Buffer.from_buffer(pcm_bytes)
|
||
|
|
|
||
|
|
# Either store the encoded packet to return at the end of the
|
||
|
|
# method or immediately call the callback with the encoded
|
||
|
|
# packet.
|
||
|
|
def store_or_callback(encoded_packet: memoryview,
|
||
|
|
samples: int,
|
||
|
|
end_of_stream: bool = False) -> None:
|
||
|
|
if callback is None:
|
||
|
|
# Store the result
|
||
|
|
results.append((
|
||
|
|
encoded_packet,
|
||
|
|
samples,
|
||
|
|
end_of_stream
|
||
|
|
))
|
||
|
|
else:
|
||
|
|
# Call the callback
|
||
|
|
callback(
|
||
|
|
encoded_packet,
|
||
|
|
samples,
|
||
|
|
end_of_stream
|
||
|
|
)
|
||
|
|
|
||
|
|
# Fill the remainder of the buffer with silence and encode it.
|
||
|
|
# The associated number of samples are only that of actual
|
||
|
|
# data, not the added silence.
|
||
|
|
def flush_buffer() -> None:
|
||
|
|
# Sanity checks to satisfy mypy
|
||
|
|
assert self._buffer_index is not None
|
||
|
|
assert self._channels is not None
|
||
|
|
assert self._buffer is not None
|
||
|
|
|
||
|
|
# If the buffer is already empty, we have no work to do
|
||
|
|
if self._buffer_index == 0:
|
||
|
|
return
|
||
|
|
|
||
|
|
# Store the number of samples currently in the buffer
|
||
|
|
samples = (
|
||
|
|
self._buffer_index
|
||
|
|
// self._channels
|
||
|
|
// ctypes.sizeof(opus.opus_int16)
|
||
|
|
)
|
||
|
|
|
||
|
|
# Fill the buffer with silence
|
||
|
|
ctypes.memset(
|
||
|
|
# destination
|
||
|
|
ctypes.byref(self._buffer, self._buffer_index),
|
||
|
|
# value
|
||
|
|
0,
|
||
|
|
# count
|
||
|
|
len(self._buffer) - self._buffer_index
|
||
|
|
)
|
||
|
|
|
||
|
|
# Encode the PCM
|
||
|
|
# As at 2020-11-05, mypy is unaware that ctype Arrays
|
||
|
|
# support the buffer protocol.
|
||
|
|
encoded_packet = self.encode(memoryview(self._buffer)) # type: ignore
|
||
|
|
|
||
|
|
# Either store the encoded packet or call the
|
||
|
|
# callback
|
||
|
|
store_or_callback(encoded_packet, samples, True)
|
||
|
|
|
||
|
|
|
||
|
|
# Copy the data remaining from the provided PCM into the
|
||
|
|
# buffer. Flush if required.
|
||
|
|
def copy_insufficient_data() -> None:
|
||
|
|
# Sanity checks to satisfy mypy
|
||
|
|
assert self._buffer is not None
|
||
|
|
|
||
|
|
# Calculate remaining data
|
||
|
|
remaining_data = len(pcm_bytes) - pcm_index
|
||
|
|
|
||
|
|
# Copy the data into the buffer.
|
||
|
|
ctypes.memmove(
|
||
|
|
# destination
|
||
|
|
ctypes.byref(self._buffer, self._buffer_index),
|
||
|
|
# source
|
||
|
|
ctypes.byref(pcm_ctypes, pcm_index),
|
||
|
|
# count
|
||
|
|
remaining_data
|
||
|
|
)
|
||
|
|
|
||
|
|
self._buffer_index += remaining_data
|
||
|
|
|
||
|
|
# If we've been asked to flush the buffer then do so
|
||
|
|
if flush:
|
||
|
|
flush_buffer()
|
||
|
|
|
||
|
|
# Loop through the provided PCM and the current buffer,
|
||
|
|
# encoding as we have full packets.
|
||
|
|
while True:
|
||
|
|
# There are two possibilities at this point: either we
|
||
|
|
# have previously unencoded data still in the buffer or we
|
||
|
|
# do not
|
||
|
|
if self._buffer_index == 0:
|
||
|
|
# We do not have unencoded data
|
||
|
|
|
||
|
|
# We are free to progress through the PCM that has
|
||
|
|
# been provided encoding frames without copying any
|
||
|
|
# bytes. Once there is insufficient data remaining
|
||
|
|
# for a complete frame, that data should be copied
|
||
|
|
# into the buffer and we have finished.
|
||
|
|
if pcm_len - pcm_index > self._frame_size_bytes:
|
||
|
|
# We have enough data remaining in the provided
|
||
|
|
# PCM to encode more than an entire frame without
|
||
|
|
# copying any data. Unfortunately, splicing a
|
||
|
|
# ctypes array copies the array. To avoid the
|
||
|
|
# copy we use memoryview see
|
||
|
|
# https://mattgwwalker.wordpress.com/2020/12/12/python-ctypes-slicing/
|
||
|
|
frame_data = memoryview(pcm_bytes)[
|
||
|
|
pcm_index:pcm_index+self._frame_size_bytes
|
||
|
|
]
|
||
|
|
|
||
|
|
# Update the PCM index
|
||
|
|
pcm_index += self._frame_size_bytes
|
||
|
|
|
||
|
|
# Store number of samples (per channel) of actual
|
||
|
|
# data
|
||
|
|
samples = (
|
||
|
|
len(frame_data)
|
||
|
|
// self._channels
|
||
|
|
// ctypes.sizeof(opus.opus_int16)
|
||
|
|
)
|
||
|
|
|
||
|
|
# Encode the PCM
|
||
|
|
encoded_packet = super().encode(frame_data)
|
||
|
|
|
||
|
|
# Either store the encoded packet or call the
|
||
|
|
# callback
|
||
|
|
store_or_callback(encoded_packet, samples)
|
||
|
|
|
||
|
|
else:
|
||
|
|
# We do not have enough data to fill a frame while
|
||
|
|
# still having data left over. Copy the data into
|
||
|
|
# the buffer.
|
||
|
|
copy_insufficient_data()
|
||
|
|
return results
|
||
|
|
|
||
|
|
else:
|
||
|
|
# We have unencoded data.
|
||
|
|
|
||
|
|
# Copy the provided PCM into the buffer (up until the
|
||
|
|
# buffer is full). If we can fill it, then we can
|
||
|
|
# encode the filled buffer and continue. If we can't
|
||
|
|
# fill it then we've finished.
|
||
|
|
data_required = len(self._buffer) - self._buffer_index
|
||
|
|
if pcm_len > data_required:
|
||
|
|
# We have sufficient data to fill the buffer and
|
||
|
|
# have data left over. Copy data into the buffer.
|
||
|
|
assert pcm_index == 0
|
||
|
|
remaining = len(self._buffer) - self._buffer_index
|
||
|
|
ctypes.memmove(
|
||
|
|
# destination
|
||
|
|
ctypes.byref(self._buffer, self._buffer_index),
|
||
|
|
# source
|
||
|
|
pcm_ctypes,
|
||
|
|
# count
|
||
|
|
remaining
|
||
|
|
)
|
||
|
|
pcm_index += remaining
|
||
|
|
self._buffer_index += remaining
|
||
|
|
assert self._buffer_index == len(self._buffer)
|
||
|
|
|
||
|
|
# Encode the PCM
|
||
|
|
encoded_packet = super().encode(
|
||
|
|
# Memoryviews of ctypes do work, even though
|
||
|
|
# mypy complains.
|
||
|
|
memoryview(self._buffer) # type: ignore
|
||
|
|
)
|
||
|
|
|
||
|
|
# Store number of samples (per channel) of actual
|
||
|
|
# data
|
||
|
|
samples = (
|
||
|
|
self._buffer_index
|
||
|
|
// self._channels
|
||
|
|
// ctypes.sizeof(opus.opus_int16)
|
||
|
|
)
|
||
|
|
|
||
|
|
# We've now processed the buffer
|
||
|
|
self._buffer_index = 0
|
||
|
|
|
||
|
|
# Either store the encoded packet or call the
|
||
|
|
# callback
|
||
|
|
store_or_callback(encoded_packet, samples)
|
||
|
|
else:
|
||
|
|
# We have insufficient data to fill the buffer
|
||
|
|
# while still having data left over. Copy the
|
||
|
|
# data into the buffer.
|
||
|
|
copy_insufficient_data()
|
||
|
|
return results
|
||
|
|
|
||
|
|
|
||
|
|
def _calc_frame_size(self):
|
||
|
|
"""Calculates the number of bytes in a frame.
|
||
|
|
|
||
|
|
If the frame size (in milliseconds) and the number of
|
||
|
|
samples per seconds have already been specified, then the
|
||
|
|
frame size in bytes is set. Otherwise, this method does
|
||
|
|
nothing.
|
||
|
|
|
||
|
|
The frame size is measured in bytes required to store the
|
||
|
|
sample.
|
||
|
|
|
||
|
|
"""
|
||
|
|
if (self._frame_size_ms is None
|
||
|
|
or self._samples_per_second is None):
|
||
|
|
return
|
||
|
|
|
||
|
|
self._frame_size_bytes = (
|
||
|
|
self._frame_size_ms
|
||
|
|
* self._samples_per_second
|
||
|
|
// 1000
|
||
|
|
* ctypes.sizeof(opus.opus_int16)
|
||
|
|
* self._channels
|
||
|
|
)
|
||
|
|
|
||
|
|
# Allocate space for the buffer
|
||
|
|
Buffer = ctypes.c_ubyte * self._frame_size_bytes
|
||
|
|
self._buffer = Buffer()
|
||
|
|
|
||
|
|
|
||
|
|
def _get_next_frame(self, add_silence=False):
|
||
|
|
"""Gets the next Opus-encoded frame.
|
||
|
|
|
||
|
|
Returns a tuple where the first item is the Opus-encoded
|
||
|
|
frame and the second item is the number of encoded samples
|
||
|
|
(per channel).
|
||
|
|
|
||
|
|
Returns None if insufficient data is available.
|
||
|
|
|
||
|
|
"""
|
||
|
|
next_frame = bytes()
|
||
|
|
samples = 0
|
||
|
|
|
||
|
|
# Ensure frame size has been specified
|
||
|
|
if self._frame_size_bytes is None:
|
||
|
|
raise PyOggError(
|
||
|
|
"Desired frame size hasn't been set. Perhaps "+
|
||
|
|
"encode() was called before set_frame_size() "+
|
||
|
|
"and set_sampling_frequency()?"
|
||
|
|
)
|
||
|
|
|
||
|
|
# Check if there's insufficient data in the buffer to fill
|
||
|
|
# a frame.
|
||
|
|
if self._frame_size_bytes > self._buffer_size:
|
||
|
|
if len(self._buffer) == 0:
|
||
|
|
# No data at all in buffer
|
||
|
|
return None
|
||
|
|
if add_silence:
|
||
|
|
# Get all remaining data
|
||
|
|
while len(self._buffer) != 0:
|
||
|
|
next_frame += self._buffer.popleft()
|
||
|
|
self._buffer_size = 0
|
||
|
|
# Store number of samples (per channel) of actual
|
||
|
|
# data
|
||
|
|
samples = (
|
||
|
|
len(next_frame)
|
||
|
|
// self._channels
|
||
|
|
// ctypes.sizeof(opus.opus_int16)
|
||
|
|
)
|
||
|
|
# Fill remainder of frame with silence
|
||
|
|
bytes_remaining = self._frame_size_bytes - len(next_frame)
|
||
|
|
next_frame += b'\x00' * bytes_remaining
|
||
|
|
return (next_frame, samples)
|
||
|
|
else:
|
||
|
|
# Insufficient data to fill a frame and we're not
|
||
|
|
# adding silence
|
||
|
|
return None
|
||
|
|
|
||
|
|
bytes_remaining = self._frame_size_bytes
|
||
|
|
while bytes_remaining > 0:
|
||
|
|
if len(self._buffer[0]) <= bytes_remaining:
|
||
|
|
# Take the whole first item
|
||
|
|
buffer_ = self._buffer.popleft()
|
||
|
|
next_frame += buffer_
|
||
|
|
bytes_remaining -= len(buffer_)
|
||
|
|
self._buffer_size -= len(buffer_)
|
||
|
|
else:
|
||
|
|
# Take only part of the buffer
|
||
|
|
|
||
|
|
# TODO: This could be more efficiently
|
||
|
|
# implemented. Rather than appending back the
|
||
|
|
# remaining data, we could just update an index
|
||
|
|
# saying where we were up to in regards to the
|
||
|
|
# first entry of the buffer.
|
||
|
|
buffer_ = self._buffer.popleft()
|
||
|
|
next_frame += buffer_[:bytes_remaining]
|
||
|
|
self._buffer_size -= bytes_remaining
|
||
|
|
# And put the unused part back into the buffer
|
||
|
|
self._buffer.appendleft(buffer_[bytes_remaining:])
|
||
|
|
bytes_remaining = 0
|
||
|
|
|
||
|
|
# Calculate number of samples (per channel)
|
||
|
|
samples = (
|
||
|
|
len(next_frame)
|
||
|
|
// self._channels
|
||
|
|
// ctypes.sizeof(opus.opus_int16)
|
||
|
|
)
|
||
|
|
|
||
|
|
return (next_frame, samples)
|