Add --audio-output-buffer

On some systems, the SDL audio callback is not called frequently enough
(for example it requests 5ms of samples every 10ms), because the output
buffer is too small.

By default, we want to use a small value (5ms) to minimize latency, but
if it does not work well, users need a way to increase it.

Refs #3793 <https://github.com/Genymobile/scrcpy/issues/3793>

app/scrcpy.1

@@ -33,6 +33,14 @@ Lower values decrease the latency, but increase the likelyhood of buffer underru
 
 Default is 50.
 
+.TP
+.BI "\-\-audio\-output\-buffer ms
+Configure the size of the SDL audio output buffer (in milliseconds).
+
+If you get "robotic" audio playback, you should test with a higher value (10). Do not change this setting otherwise.
+
+Default is 5.
+
 .TP
 .BI "\-\-audio\-codec " name
 Select an audio codec (opus, aac or raw).