Memory Safety: Medium
In the fallback code path when spa-plugins support is not compiled in,
calloc() for the output sample buffer was not checked for NULL. If the
allocation fails (e.g., due to a large n_samples value from filter
configuration), spa_memcpy would dereference a NULL pointer.
Fixed by adding a NULL check and returning NULL on allocation failure.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>