From 9e4ee500b61462c205ed588c31a045bd95215cdc Mon Sep 17 00:00:00 2001
From: Chris Robinson <chris.kcat@gmail.com>
Date: Fri, 26 Apr 2019 18:04:22 -0700
Subject: Scale the update size with sample rate changes

---
 Alc/backends/pulseaudio.cpp | 15 +++++++++------
 Alc/backends/wasapi.cpp     | 15 ++++++---------
 2 files changed, 15 insertions(+), 15 deletions(-)

(limited to 'Alc/backends')

diff --git a/Alc/backends/pulseaudio.cpp b/Alc/backends/pulseaudio.cpp
index 29fd5ae9..9561407c 100644
--- a/Alc/backends/pulseaudio.cpp
+++ b/Alc/backends/pulseaudio.cpp
@@ -1026,15 +1026,18 @@ ALCboolean PulsePlayback::reset()
     if(mDevice->Frequency != mSpec.rate)
     {
         /* Server updated our playback rate, so modify the buffer attribs
-         * accordingly. */
-        double newlen{clampd(
-            static_cast<double>(mSpec.rate)/mDevice->Frequency*mDevice->BufferSize + 0.5,
-            mDevice->UpdateSize*2, std::numeric_limits<int>::max()/mFrameSize)};
+         * accordingly.
+         */
+        const auto scale = static_cast<double>(mSpec.rate) / mDevice->Frequency;
+        const ALuint perlen{static_cast<ALuint>(clampd(scale*mDevice->UpdateSize + 0.5, 64.0,
+            8192.0))};
+        const ALuint buflen{static_cast<ALuint>(clampd(scale*mDevice->BufferSize + 0.5, perlen*2,
+            std::numeric_limits<int>::max()/mFrameSize))};
 
         mAttr.maxlength = -1;
-        mAttr.tlength = static_cast<ALuint>(newlen) * mFrameSize;
+        mAttr.tlength = buflen * mFrameSize;
         mAttr.prebuf = 0;
-        mAttr.minreq = mDevice->UpdateSize * mFrameSize;
+        mAttr.minreq = perlen * mFrameSize;
 
         op = pa_stream_set_buffer_attr(mStream, &mAttr, stream_success_callback, mLoop);
         wait_for_operation(op, mLoop);
diff --git a/Alc/backends/wasapi.cpp b/Alc/backends/wasapi.cpp
index e1a5b278..e361b7bc 100644
--- a/Alc/backends/wasapi.cpp
+++ b/Alc/backends/wasapi.cpp
@@ -789,7 +789,8 @@ HRESULT WasapiPlayback::resetProxy()
     CoTaskMemFree(wfx);
     wfx = nullptr;
 
-    REFERENCE_TIME buf_time{mDevice->BufferSize * REFTIME_PER_SEC / mDevice->Frequency};
+    const REFERENCE_TIME per_time{mDevice->UpdateSize * REFTIME_PER_SEC / mDevice->Frequency};
+    const REFERENCE_TIME buf_time{mDevice->BufferSize * REFTIME_PER_SEC / mDevice->Frequency};
 
     if(!(mDevice->Flags&DEVICE_FREQUENCY_REQUEST))
         mDevice->Frequency = OutputType.Format.nSamplesPerSec;
@@ -986,18 +987,14 @@ HRESULT WasapiPlayback::resetProxy()
         return hr;
     }
 
-    min_len = (UINT32)ScaleCeil(min_per, mDevice->Frequency, REFTIME_PER_SEC);
     /* Find the nearest multiple of the period size to the update size */
-    if(min_len < mDevice->UpdateSize)
-        min_len *= maxu((mDevice->UpdateSize + min_len/2) / min_len, 1u);
+    if(min_per < per_time)
+        min_per *= maxu((per_time + min_per/2) / min_per, 1u);
+    min_len = (UINT32)ScaleCeil(min_per, mDevice->Frequency, REFTIME_PER_SEC);
+    min_len = minu(min_len, buffer_len/2);
 
     mDevice->UpdateSize = min_len;
     mDevice->BufferSize = buffer_len;
-    if(mDevice->BufferSize <= mDevice->UpdateSize)
-    {
-        ERR("Audio client returned buffer_len < period*2; expect break up\n");
-        mDevice->UpdateSize = buffer_len / 2;
-    }
 
     hr = mClient->SetEventHandle(mNotifyEvent);
     if(FAILED(hr))
-- 
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