Reject AudioFifo frames with a different channel layout

CHANGELOG.rst

@@ -52,6 +52,7 @@ Fixes:
 - Filters added or linked after ``Graph.configure()`` are now configured on the next push or pull instead of segfaulting.
 - ``SubtitleCodecContext.decode(None)`` flushes the decoder instead of raising ``RuntimeError``, so delayed decoders such as EIA-608 closed captions return their final subtitle.
 - ``AudioFrame.planes`` no longer counts one plane too many for 8-channel planar audio (e.g. ``fltp`` with ``7.1``), which made ``planes``, ``to_ndarray()``, and ``from_ndarray()`` raise ``ValueError``, and no longer reads past the end of ``extended_data`` for more channels. By :gh-user:`ChandraChaan` in (:pr:`2502`).
+- ``AudioFifo.write()`` now raises ``ValueError`` for a frame whose channel layout differs from the first frame's, instead of reading the wrong number of channels and scrambling or over-reading the samples. By :gh-user:`ChandraChaan` in (:pr:`2505`).
 
 v19.0.2
 -------

av/audio/fifo.py

@@ -76,6 +76,10 @@ def write(self, frame: AudioFrame | None):
         elif (
             frame.ptr.format != self.template.ptr.format
             or frame.ptr.sample_rate != self.template.ptr.sample_rate
+            or lib.av_channel_layout_compare(
+                cython.address(frame.ptr.ch_layout),
+                cython.address(self.template.ptr.ch_layout),
+            )
             or (
                 frame._time_base.num
                 and self.template._time_base.num

tests/test_audiofifo.py

@@ -1,5 +1,7 @@
 from fractions import Fraction
 
+import pytest
+
 import av
 
 from .common import TestCase, fate_suite
@@ -115,3 +117,14 @@ def test_missing_time_base(self) -> None:
         assert oframe is not None
         assert oframe.pts is None and not oframe.time_base
         assert oframe.sample_rate == iframe.sample_rate
+
+    def test_layout_mismatch(self) -> None:
+        fifo = av.AudioFifo()
+        fifo.write(av.AudioFrame(format="s16", layout="mono", samples=1024))
+
+        # The FIFO was allocated for one channel, so a stereo frame would be
+        # read as mono and its samples scrambled.
+        with pytest.raises(ValueError):
+            fifo.write(av.AudioFrame(format="s16", layout="stereo", samples=1024))
+
+        assert fifo.samples == 1024