Changeset 89512 in vbox for trunk/src/VBox/Devices

Timestamp:

Jun 4, 2021 3:27:51 PM (4 years ago)

Author:

vboxsync

Message:

DrvAudio: Reduced the pre-buffering to 50% for output as well. Then we have the same for both input and output, and it's 50ms less by default (150ms). bugref:9890

File:

• trunk/src/VBox/Devices/Audio/DrvAudio.cpp (modified) (1 diff)

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

@@ -1139 +1139 @@
         if (pCfg->Backend.cFramesPreBuffering == UINT32_MAX) /* Set default pre-buffering size if nothing explicitly is set. */
         {
-            /* Pre-buffer 66% of the buffer for output streams, but only 50% for input. Capping both at 200ms. */
-            if (pCfg->enmDir == PDMAUDIODIR_OUT)
-                pCfg->Backend.cFramesPreBuffering = pCfg->Backend.cFramesBufferSize * 2 / 3;
-            else
-                pCfg->Backend.cFramesPreBuffering = pCfg->Backend.cFramesBufferSize / 2;
+            /* Pre-buffer 50% for both output & input. Capping both at 200ms.
+               The 50% reasoning being that we need to have sufficient slack space
+               in both directions as the guest DMA timer might be delayed by host
+               scheduling as well as sped up afterwards because of TM catch-up. */
             uint32_t const cFramesMax = PDMAudioPropsMilliToFrames(&pCfg->Props, 200);
+            pCfg->Backend.cFramesPreBuffering = pCfg->Backend.cFramesBufferSize / 2;
             pCfg->Backend.cFramesPreBuffering = RT_MIN(pCfg->Backend.cFramesPreBuffering, cFramesMax);
             pszWhat = "default";