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python: Add PLC interface for the python wrapper

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This commit is contained in:
Antoine Soulier
2025-05-12 15:48:01 -07:00
parent 9f1e206b34
commit 081d5e46a4
1 changed files with 21 additions and 13 deletions
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34
python/lc3.py
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@@ -472,14 +472,14 @@ class Decoder(_Base):
@typing.overload @typing.overload
def decode( def decode(
self, data: bytes | bytearray | memoryview, bit_depth: None = None self, data: bytes | bytearray | memoryview | None, bit_depth: None = None
) -> array.array[float]: ... ) -> array.array[float]: ...
@typing.overload @typing.overload
def decode(self, data: bytes | bytearray | memoryview, bit_depth: int) -> bytes: ... def decode(self, data: bytes | bytearray | memoryview | None, bit_depth: int) -> bytes: ...
def decode( def decode(
self, data: bytes | bytearray | memoryview, bit_depth: int | None = None self, data: bytes | bytearray | memoryview | None, bit_depth: int | None = None
) -> bytes | array.array[float]: ) -> bytes | array.array[float]:
""" """
Decodes an LC3 frame. Decodes an LC3 frame.
@@ -487,6 +487,8 @@ class Decoder(_Base):
The input `data` is the channels concatenation of LC3 frames in a The input `data` is the channels concatenation of LC3 frames in a
byte-like object. Interleaved PCM samples are returned according to byte-like object. Interleaved PCM samples are returned according to
the `bit_depth` indication. the `bit_depth` indication.
Setting `data` to `None` enables PLC (Packet Loss Concealment)
reconstruction for the block of LC3 frames.
When no `bit_depth` is defined, it's a vector of floating point values When no `bit_depth` is defined, it's a vector of floating point values
from -1 to 1, coding the sample levels. When `bit_depth` is defined, from -1 to 1, coding the sample levels. When `bit_depth` is defined,
it returns a byte array, each sample coded on `bit_depth` bits. it returns a byte array, each sample coded on `bit_depth` bits.
@@ -500,22 +502,28 @@ class Decoder(_Base):
pcm_len = num_channels * self.get_frame_samples() pcm_len = num_channels * self.get_frame_samples()
pcm_buffer = (pcm_t * pcm_len)() pcm_buffer = (pcm_t * pcm_len)()
data_buffer = bytearray(data) if data is not None:
data_offset = 0 data_buffer = bytearray(data)
data_offset = 0
for ich, decoder in enumerate(self.__decoders): for ich, decoder in enumerate(self.__decoders):
pcm_offset = ich * ctypes.sizeof(pcm_t) pcm_offset = ich * ctypes.sizeof(pcm_t)
pcm = (pcm_t * (pcm_len - ich)).from_buffer(pcm_buffer, pcm_offset) pcm = (pcm_t * (pcm_len - ich)).from_buffer(pcm_buffer, pcm_offset)
data_size = len(data_buffer) // num_channels + int( if data is None:
ich < len(data_buffer) % num_channels ret = self.lib.lc3_decode(
) decoder, None, 0, pcm_fmt, pcm, self.num_channels
buf = (c_byte * data_size).from_buffer(data_buffer, data_offset) )
data_offset += data_size else:
data_size = len(data_buffer) // num_channels + int(
ich < len(data_buffer) % num_channels
)
buf = (c_byte * data_size).from_buffer(data_buffer, data_offset)
data_offset += data_size
ret = self.lib.lc3_decode(
decoder, buf, len(buf), pcm_fmt, pcm, self.num_channels
)
ret = self.lib.lc3_decode(
decoder, buf, len(buf), pcm_fmt, pcm, self.num_channels
)
if ret < 0: if ret < 0:
raise InvalidArgumentError("Bad parameters") raise InvalidArgumentError("Bad parameters")