Changeset 76700 in vbox

Timestamp:

Jan 8, 2019 10:14:41 AM (6 years ago)

Author:

vboxsync

Message:

Audio/AC97: Added support for adaptive device scheduling rates based on the stream's given Hz rate.

File:

• trunk/src/VBox/Devices/Audio/DevIchAc97.cpp (modified) (2 diffs)

trunk/src/VBox/Devices/Audio/DevIchAc97.cpp

@@ -1963 +1963 @@
     PAUDMIXSINK pMixSink = NULL;
 
-    /* Set scheduling hint (if available). */
-    if (pThis->uTimerHz)
-        Cfg.Device.uSchedulingHintMs = 1000 /* ms */ / pThis->uTimerHz;
-
     Cfg.Props.cChannels = 2;
     Cfg.Props.cBytes    = 2 /* 16-bit */;
@@ -2044 +2040 @@
 
                 /*
-                 * Set the stream's timer Hz rate.
-                 *
-                 * Currently we simply apply the global Hz rate.
-                 * This might needs tweaking as we add surround support and/or channel striping later. */
-                pStream->State.uTimerHz = pThis->uTimerHz;
+                 * Set the stream's timer Hz rate, based on the PCM properties Hz rate.
+                 */
+                if (pThis->uTimerHz == AC97_TIMER_HZ_DEFAULT) /* Make sure that we don't have any custom Hz rate set we want to enforce */
+                {
+                    if (Cfg.Props.uHz > 44100) /* E.g. 48000 Hz. */
+                        pStream->State.uTimerHz = 200;
+                    else /* Just take the global Hz rate otherwise. */
+                        pStream->State.uTimerHz = pThis->uTimerHz;
+                }
+                else
+                    pStream->State.uTimerHz = pThis->uTimerHz;
+
+                /* Set scheduling hint (if available). */
+                if (pStream->State.uTimerHz)
+                    Cfg.Device.uSchedulingHintMs = 1000 /* ms */ / pStream->State.uTimerHz;
 
                 /*