493 lines
14 KiB
Python
493 lines
14 KiB
Python
# SPDX-License-Identifier: MIT
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from __future__ import annotations
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import array
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import ctypes
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import ctypes.util
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import logging
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import math
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import os.path
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import struct
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import sys
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from typing import (
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TYPE_CHECKING,
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Any,
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Callable,
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List,
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Literal,
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Optional,
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Tuple,
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Type,
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TypedDict,
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TypeVar,
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overload,
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)
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from .errors import DiscordException
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from .utils import MISSING
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if TYPE_CHECKING:
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T = TypeVar("T")
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BAND_CTL = Literal["narrow", "medium", "wide", "superwide", "full"]
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SIGNAL_CTL = Literal["auto", "voice", "music"]
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class BandCtl(TypedDict):
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narrow: int
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medium: int
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wide: int
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superwide: int
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full: int
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class SignalCtl(TypedDict):
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auto: int
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voice: int
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music: int
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__all__ = (
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"Encoder",
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"OpusError",
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"OpusNotLoaded",
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)
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_log = logging.getLogger(__name__)
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c_int_ptr = ctypes.POINTER(ctypes.c_int)
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c_int16_ptr = ctypes.POINTER(ctypes.c_int16)
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c_float_ptr = ctypes.POINTER(ctypes.c_float)
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_lib: Any = MISSING
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class EncoderStruct(ctypes.Structure):
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pass
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class DecoderStruct(ctypes.Structure):
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pass
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EncoderStructPtr = ctypes.POINTER(EncoderStruct)
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DecoderStructPtr = ctypes.POINTER(DecoderStruct)
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## Some constants from opus_defines.h
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# Error codes
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OK = 0
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BAD_ARG = -1
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# Encoder CTLs
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APPLICATION_AUDIO = 2049
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APPLICATION_VOIP = 2048
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APPLICATION_LOWDELAY = 2051
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CTL_SET_BITRATE = 4002
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CTL_SET_BANDWIDTH = 4008
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CTL_SET_FEC = 4012
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CTL_SET_PLP = 4014
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CTL_SET_SIGNAL = 4024
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# Decoder CTLs
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CTL_SET_GAIN = 4034
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CTL_LAST_PACKET_DURATION = 4039
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band_ctl: BandCtl = {
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"narrow": 1101,
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"medium": 1102,
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"wide": 1103,
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"superwide": 1104,
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"full": 1105,
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}
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signal_ctl: SignalCtl = {
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"auto": -1000,
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"voice": 3001,
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"music": 3002,
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}
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def _err_lt(result: int, func: Callable, args: List) -> int:
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if result < OK:
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_log.info("error has happened in %s", func.__name__)
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raise OpusError(result)
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return result
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def _err_ne(result: T, func: Callable, args: List) -> T:
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ret = args[-1]._obj
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if ret.value != OK:
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_log.info("error has happened in %s", func.__name__)
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raise OpusError(ret.value)
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return result
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# A list of exported functions.
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# The first argument is obviously the name.
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# The second one are the types of arguments it takes.
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# The third is the result type.
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# The fourth is the error handler.
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exported_functions: List[
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Tuple[str, Optional[List[Type[ctypes._CData]]], Optional[Type[ctypes._CData]], Any]
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] = [
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# Generic
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("opus_get_version_string", [], ctypes.c_char_p, None),
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("opus_strerror", [ctypes.c_int], ctypes.c_char_p, None),
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# Encoder functions
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("opus_encoder_get_size", [ctypes.c_int], ctypes.c_int, None),
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(
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"opus_encoder_create",
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[ctypes.c_int, ctypes.c_int, ctypes.c_int, c_int_ptr],
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EncoderStructPtr,
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_err_ne,
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),
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(
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"opus_encode",
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[EncoderStructPtr, c_int16_ptr, ctypes.c_int, ctypes.c_char_p, ctypes.c_int32],
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ctypes.c_int32,
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_err_lt,
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),
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(
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"opus_encode_float",
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[EncoderStructPtr, c_float_ptr, ctypes.c_int, ctypes.c_char_p, ctypes.c_int32],
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ctypes.c_int32,
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_err_lt,
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),
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("opus_encoder_ctl", [EncoderStructPtr, ctypes.c_int], ctypes.c_int32, _err_lt),
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("opus_encoder_destroy", [EncoderStructPtr], None, None),
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# Decoder functions
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("opus_decoder_get_size", [ctypes.c_int], ctypes.c_int, None),
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("opus_decoder_create", [ctypes.c_int, ctypes.c_int, c_int_ptr], DecoderStructPtr, _err_ne),
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(
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"opus_decode",
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[
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DecoderStructPtr,
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ctypes.c_char_p,
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ctypes.c_int32,
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c_int16_ptr,
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ctypes.c_int,
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ctypes.c_int,
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],
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ctypes.c_int,
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_err_lt,
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),
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(
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"opus_decode_float",
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[
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DecoderStructPtr,
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ctypes.c_char_p,
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ctypes.c_int32,
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c_float_ptr,
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ctypes.c_int,
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ctypes.c_int,
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],
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ctypes.c_int,
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_err_lt,
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),
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("opus_decoder_ctl", [DecoderStructPtr, ctypes.c_int], ctypes.c_int32, _err_lt),
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("opus_decoder_destroy", [DecoderStructPtr], None, None),
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(
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"opus_decoder_get_nb_samples",
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[DecoderStructPtr, ctypes.c_char_p, ctypes.c_int32],
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ctypes.c_int,
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_err_lt,
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),
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# Packet functions
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("opus_packet_get_bandwidth", [ctypes.c_char_p], ctypes.c_int, _err_lt),
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("opus_packet_get_nb_channels", [ctypes.c_char_p], ctypes.c_int, _err_lt),
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("opus_packet_get_nb_frames", [ctypes.c_char_p, ctypes.c_int], ctypes.c_int, _err_lt),
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("opus_packet_get_samples_per_frame", [ctypes.c_char_p, ctypes.c_int], ctypes.c_int, _err_lt),
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]
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def libopus_loader(name: str) -> Any:
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# create the library...
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lib = ctypes.cdll.LoadLibrary(name)
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# register the functions...
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for item in exported_functions:
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func: ctypes._NamedFuncPointer = getattr(lib, item[0])
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try:
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if item[1]:
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func.argtypes = item[1]
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func.restype = item[2]
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except KeyError:
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pass
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try:
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if item[3]:
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func.errcheck = item[3]
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except KeyError:
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_log.exception("Error assigning check function to %s", func)
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return lib
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def _load_default() -> bool:
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global _lib # noqa: PLW0603
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try:
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if sys.platform == "win32":
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_basedir = os.path.dirname(os.path.abspath(__file__))
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_bitness = struct.calcsize("P") * 8
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_target = "x64" if _bitness > 32 else "x86"
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_filename = os.path.join(_basedir, "bin", f"libopus-0.{_target}.dll")
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_lib = libopus_loader(_filename) # noqa: PLW0603
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else:
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path = ctypes.util.find_library("opus")
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if not path:
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raise AssertionError("could not find the opus library")
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_lib = libopus_loader(path) # noqa: PLW0603
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except Exception:
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_lib = MISSING
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return _lib is not MISSING
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def load_opus(name: str) -> None:
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"""Loads the libopus shared library for use with voice.
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If this function is not called then the library uses the function
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:func:`ctypes.util.find_library` and then loads that one if available.
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Not loading a library and attempting to use PCM based AudioSources will
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lead to voice not working.
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This function propagates the exceptions thrown.
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.. warning::
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The bitness of the library must match the bitness of your python
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interpreter. If the library is 64-bit then your python interpreter
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must be 64-bit as well. Usually if there's a mismatch in bitness then
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the load will throw an exception.
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.. note::
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On Windows, this function should not need to be called as the binaries
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are automatically loaded.
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.. note::
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On Windows, the .dll extension is not necessary. However, on Linux
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the full extension is required to load the library, e.g. ``libopus.so.1``.
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On Linux however, :func:`ctypes.util.find_library` will usually find the library automatically
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without you having to call this.
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Parameters
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----------
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name: :class:`str`
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The filename of the shared library.
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"""
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global _lib # noqa: PLW0603
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_lib = libopus_loader(name)
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def is_loaded() -> bool:
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"""Function to check if opus lib is successfully loaded either
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via the :func:`ctypes.util.find_library` call of :func:`load_opus`.
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This must return ``True`` for voice to work.
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Returns
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-------
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:class:`bool`
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Indicates if the opus library has been loaded.
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"""
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return _lib is not MISSING
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class OpusError(DiscordException):
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"""An exception that is thrown for libopus related errors.
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Attributes
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----------
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code: :class:`int`
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The error code returned.
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"""
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def __init__(self, code: int) -> None:
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self.code: int = code
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msg = _lib.opus_strerror(self.code).decode("utf-8")
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_log.info('"%s" has happened', msg)
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super().__init__(msg)
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class OpusNotLoaded(DiscordException):
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"""An exception that is thrown for when libopus is not loaded."""
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pass
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class _OpusStruct:
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SAMPLING_RATE = 48000
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CHANNELS = 2
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FRAME_LENGTH = 20 # in milliseconds
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SAMPLE_SIZE = struct.calcsize("h") * CHANNELS
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SAMPLES_PER_FRAME = int(SAMPLING_RATE / 1000 * FRAME_LENGTH)
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FRAME_SIZE = SAMPLES_PER_FRAME * SAMPLE_SIZE
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@staticmethod
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def get_opus_version() -> str:
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if not is_loaded() and not _load_default():
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raise OpusNotLoaded
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return _lib.opus_get_version_string().decode("utf-8")
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class Encoder(_OpusStruct):
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def __init__(self, application: int = APPLICATION_AUDIO) -> None:
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_OpusStruct.get_opus_version()
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self.application: int = application
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self._state: EncoderStruct = self._create_state()
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self.set_bitrate(128)
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self.set_fec(True)
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self.set_expected_packet_loss_percent(0.15)
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self.set_bandwidth("full")
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self.set_signal_type("auto")
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def __del__(self) -> None:
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if hasattr(self, "_state"):
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_lib.opus_encoder_destroy(self._state)
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# This is a destructor, so it's okay to assign None
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self._state = None # type: ignore
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def _create_state(self) -> EncoderStruct:
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ret = ctypes.c_int()
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return _lib.opus_encoder_create(
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self.SAMPLING_RATE, self.CHANNELS, self.application, ctypes.byref(ret)
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)
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def set_bitrate(self, kbps: int) -> int:
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kbps = min(512, max(16, int(kbps)))
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_lib.opus_encoder_ctl(self._state, CTL_SET_BITRATE, kbps * 1024)
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return kbps
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def set_bandwidth(self, req: BAND_CTL) -> None:
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if req not in band_ctl:
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raise KeyError(
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f'{req!r} is not a valid bandwidth setting. Try one of: {",".join(band_ctl)}'
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)
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k = band_ctl[req]
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_lib.opus_encoder_ctl(self._state, CTL_SET_BANDWIDTH, k)
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def set_signal_type(self, req: SIGNAL_CTL) -> None:
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if req not in signal_ctl:
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raise KeyError(
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f'{req!r} is not a valid bandwidth setting. Try one of: {",".join(signal_ctl)}'
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)
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k = signal_ctl[req]
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_lib.opus_encoder_ctl(self._state, CTL_SET_SIGNAL, k)
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def set_fec(self, enabled: bool = True) -> None:
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_lib.opus_encoder_ctl(self._state, CTL_SET_FEC, 1 if enabled else 0)
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def set_expected_packet_loss_percent(self, percentage: float) -> None:
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_lib.opus_encoder_ctl(self._state, CTL_SET_PLP, min(100, max(0, int(percentage * 100))))
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def encode(self, pcm: bytes, frame_size: int) -> bytes:
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max_data_bytes = len(pcm)
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# bytes can be used to reference pointer
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pcm_ptr = ctypes.cast(pcm, c_int16_ptr) # type: ignore
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data = (ctypes.c_char * max_data_bytes)()
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ret = _lib.opus_encode(self._state, pcm_ptr, frame_size, data, max_data_bytes)
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return array.array("b", data[:ret]).tobytes()
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class Decoder(_OpusStruct):
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def __init__(self) -> None:
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_OpusStruct.get_opus_version()
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self._state: DecoderStruct = self._create_state()
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def __del__(self) -> None:
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if hasattr(self, "_state"):
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_lib.opus_decoder_destroy(self._state)
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# This is a destructor, so it's okay to assign None
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self._state = None # type: ignore
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def _create_state(self) -> DecoderStruct:
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ret = ctypes.c_int()
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return _lib.opus_decoder_create(self.SAMPLING_RATE, self.CHANNELS, ctypes.byref(ret))
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@staticmethod
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def packet_get_nb_frames(data: bytes) -> int:
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"""Gets the number of frames in an Opus packet"""
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return _lib.opus_packet_get_nb_frames(data, len(data))
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@staticmethod
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def packet_get_nb_channels(data: bytes) -> int:
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"""Gets the number of channels in an Opus packet"""
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return _lib.opus_packet_get_nb_channels(data)
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@classmethod
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def packet_get_samples_per_frame(cls, data: bytes) -> int:
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"""Gets the number of samples per frame from an Opus packet"""
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return _lib.opus_packet_get_samples_per_frame(data, cls.SAMPLING_RATE)
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def _set_gain(self, adjustment: int) -> int:
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"""Configures decoder gain adjustment.
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Scales the decoded output by a factor specified in Q8 dB units.
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This has a maximum range of -32768 to 32767 inclusive, and returns
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OPUS_BAD_ARG (-1) otherwise. The default is zero indicating no adjustment.
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This setting survives decoder reset (irrelevant for now).
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gain = 10**x/(20.0*256)
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(from opus_defines.h)
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"""
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return _lib.opus_decoder_ctl(self._state, CTL_SET_GAIN, adjustment)
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def set_gain(self, dB: float) -> int:
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"""Sets the decoder gain in dB, from -128 to 128."""
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dB_Q8 = max(-32768, min(32767, round(dB * 256))) # dB * 2^n where n is 8 (Q8)
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return self._set_gain(dB_Q8)
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def set_volume(self, mult: float) -> int:
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"""Sets the output volume as a float percent, i.e. 0.5 for 50%, 1.75 for 175%, etc."""
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return self.set_gain(20 * math.log10(mult)) # amplitude ratio
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def _get_last_packet_duration(self) -> int:
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"""Gets the duration (in samples) of the last packet successfully decoded or concealed."""
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ret = ctypes.c_int32()
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_lib.opus_decoder_ctl(self._state, CTL_LAST_PACKET_DURATION, ctypes.byref(ret))
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return ret.value
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@overload
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def decode(self, data: bytes, *, fec: bool) -> bytes:
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...
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@overload
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def decode(self, data: Literal[None], *, fec: Literal[False]) -> bytes:
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...
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def decode(self, data: Optional[bytes], *, fec: bool = False) -> bytes:
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if data is None and fec:
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raise TypeError("Invalid arguments: FEC cannot be used with null data")
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if data is None:
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frame_size = self._get_last_packet_duration() or self.SAMPLES_PER_FRAME
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channel_count = self.CHANNELS
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else:
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frames = self.packet_get_nb_frames(data)
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channel_count = self.packet_get_nb_channels(data)
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samples_per_frame = self.packet_get_samples_per_frame(data)
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frame_size = frames * samples_per_frame
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pcm = (ctypes.c_int16 * (frame_size * channel_count))()
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pcm_ptr = ctypes.cast(pcm, c_int16_ptr)
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ret = _lib.opus_decode(
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self._state, data, len(data) if data else 0, pcm_ptr, frame_size, fec
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)
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return array.array("h", pcm[: ret * channel_count]).tobytes()
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