support sliced memoryviews in AudioFrame and VideoFrame

Author: theomonnom

livekit-rtc/livekit/rtc/_utils.py

@@ -40,28 +40,29 @@ def task_done_logger(task: asyncio.Task) -> None:
         return
 
 
-def _buffer_supported_or_raise(
+def _ensure_compatible_buffer(
     data: Union[bytes, bytearray, memoryview],
-) -> None:
-    """Validate a buffer for FFI use.
+) -> Union[bytes, bytearray, memoryview]:
+    """Validate and normalize a buffer for FFI use.
 
-    Raises clear errors for non-contiguous or sliced memoryviews.
+    Sliced memoryviews are materialized because get_address cannot
+    reliably resolve their offset for all buffer types.
     """
     if isinstance(data, memoryview):
         if not data.contiguous:
             raise ValueError("memoryview must be contiguous")
         if data.nbytes != len(data.obj):  # type: ignore[arg-type]
-            raise ValueError("sliced memoryviews are not supported")
+            return bytearray(data) if not data.readonly else bytes(data)
     elif not isinstance(data, (bytes, bytearray)):
         raise TypeError(f"expected bytes, bytearray, or memoryview, got {type(data)}")
+    return data
 
 
-def get_address(data) -> int:
+def get_address(data: Union[bytes, bytearray, memoryview]) -> int:
     if isinstance(data, memoryview):
-        _buffer_supported_or_raise(data)
         if not data.readonly:
             return ctypes.addressof(ctypes.c_char.from_buffer(data))
-        data = data.obj
+        data = data.obj  # type: ignore[assignment]
     if isinstance(data, bytearray):
         return ctypes.addressof(ctypes.c_char.from_buffer(data))
     if isinstance(data, bytes):

livekit-rtc/livekit/rtc/audio_frame.py

@@ -15,7 +15,7 @@
 import ctypes
 from ._ffi_client import FfiHandle
 from ._proto import audio_frame_pb2 as proto_audio
-from ._utils import _buffer_supported_or_raise, get_address
+from ._utils import _ensure_compatible_buffer, get_address
 from typing import Any, Union
 
 
@@ -49,7 +49,7 @@ def __init__(
         Raises:
             ValueError: If the length of `data` is smaller than the required size.
         """
-        _buffer_supported_or_raise(data)
+        data = _ensure_compatible_buffer(data)
 
         min_size = num_channels * samples_per_channel * ctypes.sizeof(ctypes.c_int16)
         data_len = len(data)

livekit-rtc/livekit/rtc/video_frame.py

@@ -18,7 +18,7 @@
 from ._proto import ffi_pb2 as proto
 from typing import List, Optional
 from ._ffi_client import FfiClient, FfiHandle
-from ._utils import _buffer_supported_or_raise, get_address
+from ._utils import _ensure_compatible_buffer, get_address
 
 from typing import Any
 
@@ -48,7 +48,7 @@ def __init__(
                 (e.g., RGBA, BGRA, RGB24, etc.).
             data (Union[bytes, bytearray, memoryview]): The raw pixel data for the video frame.
         """
-        _buffer_supported_or_raise(data)
+        data = _ensure_compatible_buffer(data)
 
         self._width = width
         self._height = height