From e3d561fb842fa9ea986064a9a73001a5889f15d8 Mon Sep 17 00:00:00 2001
From: Fernando Sahmkow <fsahmkow27@gmail.com>
Date: Fri, 29 May 2020 17:37:57 -0400
Subject: [PATCH] Audio: Correct buffer release for host timing.

---
 src/audio_core/stream.cpp | 15 ++++++++++++++-
 src/audio_core/stream.h   |  3 +++
 src/core/core_timing.h    |  5 +++++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/audio_core/stream.cpp b/src/audio_core/stream.cpp
index 6d5539b6bd..dfc4805d97 100644
--- a/src/audio_core/stream.cpp
+++ b/src/audio_core/stream.cpp
@@ -66,6 +66,15 @@ s64 Stream::GetBufferReleaseNS(const Buffer& buffer) const {
     return ns.count();
 }
 
+s64 Stream::GetBufferReleaseNSHostTiming(const Buffer& buffer) const {
+    const std::size_t num_samples{buffer.GetSamples().size() / GetNumChannels()};
+    /// DSP signals before playing the last sample, in HLE we emulate this in this way
+    s64 base_samples = std::max<s64>(static_cast<s64>(num_samples) - 1, 0);
+    const auto ns =
+        std::chrono::nanoseconds((static_cast<u64>(base_samples) * 1000000000ULL) / sample_rate);
+    return ns.count();
+}
+
 static void VolumeAdjustSamples(std::vector<s16>& samples, float game_volume) {
     const float volume{std::clamp(Settings::Volume() - (1.0f - game_volume), 0.0f, 1.0f)};
 
@@ -105,7 +114,11 @@ void Stream::PlayNextBuffer() {
 
     sink_stream.EnqueueSamples(GetNumChannels(), active_buffer->GetSamples());
 
-    core_timing.ScheduleEvent(GetBufferReleaseNS(*active_buffer), release_event, {});
+    if (core_timing.IsHostTiming()) {
+        core_timing.ScheduleEvent(GetBufferReleaseNSHostTiming(*active_buffer), release_event, {});
+    } else {
+        core_timing.ScheduleEvent(GetBufferReleaseNS(*active_buffer), release_event, {});
+    }
 }
 
 void Stream::ReleaseActiveBuffer() {
diff --git a/src/audio_core/stream.h b/src/audio_core/stream.h
index 0663ce4354..e309d60fe3 100644
--- a/src/audio_core/stream.h
+++ b/src/audio_core/stream.h
@@ -98,6 +98,9 @@ private:
     /// Gets the number of core cycles when the specified buffer will be released
     s64 GetBufferReleaseNS(const Buffer& buffer) const;
 
+    /// Gets the number of core cycles when the specified buffer will be released
+    s64 GetBufferReleaseNSHostTiming(const Buffer& buffer) const;
+
     u32 sample_rate;                  ///< Sample rate of the stream
     Format format;                    ///< Format of the stream
     float game_volume = 1.0f;         ///< The volume the game currently has set
diff --git a/src/core/core_timing.h b/src/core/core_timing.h
index ed5de9b97a..72faaab647 100644
--- a/src/core/core_timing.h
+++ b/src/core/core_timing.h
@@ -72,6 +72,11 @@ public:
         this->is_multicore = is_multicore;
     }
 
+    /// Check if it's using host timing.
+    bool IsHostTiming() const {
+        return is_multicore;
+    }
+
     /// Pauses/Unpauses the execution of the timer thread.
     void Pause(bool is_paused);