ao_wasapi: add `--wasapi-exclusive-buffer` option

This allows users to set buffer duration in exclusive mode. We have
been using the default device period as the buffer size and it is
robust enough in most cases. However, on some devices there are
horrible glitches after a stream reset. Unfortunately, the issue is not
consistently reproducible, but using a smaller buffer size (e.g., the
minimum device period) seems to resolve the problem.

Fixes #13715.

1 files changed, 15 insertions, 0 deletions

diff --git a/DOCS/man/ao.rst b/DOCS/man/ao.rst
index 4ac1cc52ee..78dfed3b51 100644
--- a/DOCS/man/ao.rst
+++ b/DOCS/man/ao.rst
@@ -297,3 +297,18 @@ Available audio output drivers are:
 
 ``wasapi``
     Audio output to the Windows Audio Session API.
+
+    The following global options are supported by this audio output:
+
+    ``--wasapi-exclusive-buffer=<default|min|1-2000000>``
+        Set buffer duration in exclusive mode (i.e., with
+        ``--audio-exclusive=yes``). ``default`` and ``min`` use the default and
+        minimum device period reported by WASAPI, respectively. You can also
+        directly specify the buffer duration in microseconds, in which case a
+        duration shorter than the minimum device period will be rounded up to
+        the minimum period.
+
+        The default buffer duration should provide robust playback in most
+        cases, but reportedly on some devices there are glitches following
+        stream resets under the default setting. In such cases, specifying a
+        shorter duration might help.