audio_core: Only perform audio stretching if below full speed. (#7201)

src/audio_core/dsp_interface.cpp

@@ -13,7 +13,8 @@
 
 namespace AudioCore {
 
-DspInterface::DspInterface() = default;
+DspInterface::DspInterface(Core::System& system_) : system(system_) {}
+
 DspInterface::~DspInterface() = default;
 
 void DspInterface::SetSink(AudioCore::SinkType sink_type, std::string_view audio_device) {
@@ -32,13 +33,7 @@ Sink& DspInterface::GetSink() {
 }
 
 void DspInterface::EnableStretching(bool enable) {
-    if (perform_time_stretching == enable)
-        return;
-
-    if (!enable) {
-        flushing_time_stretcher = true;
-    }
-    perform_time_stretching = enable;
+    enable_time_stretching = enable;
 }
 
 void DspInterface::OutputFrame(StereoFrame16 frame) {
@@ -47,7 +42,7 @@ void DspInterface::OutputFrame(StereoFrame16 frame) {
 
     fifo.Push(frame.data(), frame.size());
 
-    auto video_dumper = Core::System::GetInstance().GetVideoDumper();
+    auto video_dumper = system.GetVideoDumper();
     if (video_dumper && video_dumper->IsDumping()) {
         video_dumper->AddAudioFrame(std::move(frame));
     }
@@ -59,15 +54,24 @@ void DspInterface::OutputSample(std::array<s16, 2> sample) {
 
     fifo.Push(&sample, 1);
 
-    auto video_dumper = Core::System::GetInstance().GetVideoDumper();
+    auto video_dumper = system.GetVideoDumper();
     if (video_dumper && video_dumper->IsDumping()) {
         video_dumper->AddAudioSample(std::move(sample));
     }
 }
 
 void DspInterface::OutputCallback(s16* buffer, std::size_t num_frames) {
+    // Determine if we should stretch based on the current emulation speed.
+    const auto perf_stats = system.GetLastPerfStats();
+    const auto should_stretch = enable_time_stretching && perf_stats.emulation_speed <= 95;
+    if (performing_time_stretching && !should_stretch) {
+        // If we just stopped stretching, flush the stretcher before returning to normal output.
+        flushing_time_stretcher = true;
+    }
+    performing_time_stretching = should_stretch;
+
     std::size_t frames_written = 0;
-    if (perform_time_stretching) {
+    if (performing_time_stretching) {
         const std::vector<s16> in{fifo.Pop()};
         const std::size_t num_in{in.size() / 2};
         frames_written = time_stretcher.Process(in.data(), num_in, buffer, num_frames);

src/audio_core/dsp_interface.h

@@ -13,6 +13,10 @@
 #include "common/ring_buffer.h"
 #include "core/memory.h"
 
+namespace Core {
+class System;
+} // namespace Core
+
 namespace Service::DSP {
 enum class InterruptType : u32;
 } // namespace Service::DSP
@@ -24,7 +28,7 @@ enum class SinkType : u32;
 
 class DspInterface {
 public:
-    DspInterface();
+    DspInterface(Core::System& system_);
     virtual ~DspInterface();
 
     DspInterface(const DspInterface&) = delete;
@@ -110,7 +114,10 @@ private:
     void FlushResidualStretcherAudio();
     void OutputCallback(s16* buffer, std::size_t num_frames);
 
-    std::atomic<bool> perform_time_stretching = false;
+    Core::System& system;
+
+    std::atomic<bool> enable_time_stretching = false;
+    std::atomic<bool> performing_time_stretching = false;
     std::atomic<bool> flushing_time_stretcher = false;
     Common::RingBuffer<s16, 0x2000, 2> fifo;
     std::array<s16, 2> last_frame{};

src/audio_core/hle/hle.cpp

@@ -31,7 +31,10 @@ using InterruptType = Service::DSP::InterruptType;
 namespace AudioCore {
 
 DspHle::DspHle()
-    : DspHle(Core::System::GetInstance().Memory(), Core::System::GetInstance().CoreTiming()) {}
+    : DspHle(Core::System::GetInstance(), Core::System::GetInstance().Memory(),
+             Core::System::GetInstance().CoreTiming()) {}
+
+DspHle::DspHle(Core::System& system) : DspHle(system, system.Memory(), system.CoreTiming()) {}
 
 template <class Archive>
 void DspHle::serialize(Archive& ar, const unsigned int) {
@@ -442,8 +445,8 @@ void DspHle::Impl::AudioTickCallback(s64 cycles_late) {
     core_timing.ScheduleEvent(audio_frame_ticks - cycles_late, tick_event);
 }
 
-DspHle::DspHle(Memory::MemorySystem& memory, Core::Timing& timing)
-    : impl(std::make_unique<Impl>(*this, memory, timing)) {}
+DspHle::DspHle(Core::System& system, Memory::MemorySystem& memory, Core::Timing& timing)
+    : DspInterface(system), impl(std::make_unique<Impl>(*this, memory, timing)) {}
 DspHle::~DspHle() = default;
 
 u16 DspHle::RecvData(u32 register_number) {

src/audio_core/hle/hle.h

@@ -14,6 +14,10 @@
 #include "core/hle/service/dsp/dsp_dsp.h"
 #include "core/memory.h"
 
+namespace Core {
+class Timing;
+}
+
 namespace Memory {
 class MemorySystem;
 }
@@ -22,7 +26,8 @@ namespace AudioCore {
 
 class DspHle final : public DspInterface {
 public:
-    explicit DspHle(Memory::MemorySystem& memory, Core::Timing& timing);
+    explicit DspHle(Core::System& system);
+    explicit DspHle(Core::System& system, Memory::MemorySystem& memory, Core::Timing& timing);
     ~DspHle();
 
     u16 RecvData(u32 register_number) override;

src/audio_core/lle/lle.cpp

@@ -468,8 +468,12 @@ void DspLle::UnloadComponent() {
     impl->UnloadComponent();
 }
 
-DspLle::DspLle(Memory::MemorySystem& memory, Core::Timing& timing, bool multithread)
-    : impl(std::make_unique<Impl>(timing, multithread)) {
+DspLle::DspLle(Core::System& system, bool multithread)
+    : DspLle(system, system.Memory(), system.CoreTiming(), multithread) {}
+
+DspLle::DspLle(Core::System& system, Memory::MemorySystem& memory, Core::Timing& timing,
+               bool multithread)
+    : DspInterface(system), impl(std::make_unique<Impl>(timing, multithread)) {
     Teakra::AHBMCallback ahbm;
     ahbm.read8 = [&memory](u32 address) -> u8 {
         return *memory.GetFCRAMPointer(address - Memory::FCRAM_PADDR);

src/audio_core/lle/lle.h

@@ -11,11 +11,17 @@ namespace Core {
 class Timing;
 }
 
+namespace Memory {
+class MemorySystem;
+}
+
 namespace AudioCore {
 
 class DspLle final : public DspInterface {
 public:
-    explicit DspLle(Memory::MemorySystem& memory, Core::Timing& timing, bool multithread);
+    explicit DspLle(Core::System& system, bool multithread);
+    explicit DspLle(Core::System& system, Memory::MemorySystem& memory, Core::Timing& timing,
+                    bool multithread);
     ~DspLle() override;
 
     u16 RecvData(u32 register_number) override;