af_rubberband: add af-command and option to change the pitch

This allows both fixed and dynamic control over the audio pitch using
librubberband, which was previously not exposed to the user.

1 files changed, 13 insertions, 2 deletions

diff --git a/DOCS/man/af.rst b/DOCS/man/af.rst
index 71b5bbf975..31d365722f 100644
--- a/DOCS/man/af.rst
+++ b/DOCS/man/af.rst
@@ -413,9 +413,13 @@ Available filters are:
 ``rubberband``
     High quality pitch correction with librubberband. This can be used in place
     of ``scaletempo``, and will be used to adjust audio pitch when playing
-    at speed different from normal.
+    at speed different from normal. It can also be used to adjust audio pitch
+    without changing playback speed.
 
-    This filter has a number of sub-options. You can list them with
+    ``<pitch-scale>``
+        Sets the pitch scaling factor. Frequencies are multiplied by this value.
+
+    This filter has a number of additional sub-options. You can list them with
     ``mpv --af=rubberband=help``. This will also show the default values
     for each option. The options are not documented here, because they are
     merely passed to librubberband. Look at the librubberband documentation
@@ -424,6 +428,13 @@ Available filters are:
     (The mapping of the mpv rubberband filter sub-option names and values to
     those of librubberband follows a simple pattern: ``"Option" + Name + Value``.)
 
+    This filter supports the following ``af-command`` commands:
+
+    ``set-pitch``
+        Set the ``<pitch-scale>`` argument dynamically. This can be used to
+        change the playback pitch at runtime. Note that speed is controlled
+        using the standard ``speed`` property, not ``af-command``.
+
 ``lavfi=graph``
     Filter audio using FFmpeg's libavfilter.