From dd29365970e06a1e40b06714a8fed0fcfffbbd1d Mon Sep 17 00:00:00 2001
From: Gliniak <Gliniak93@gmail.com>
Date: Mon, 1 Dec 2025 23:57:53 +0100
Subject: [PATCH] [APU] Switched to New XMA decoder as default

- Added codepath for "consume only" pass. This should resolve constant clicking in Source engine games.
- Added smaller performance improvements to decoder
---
 src/xenia/apu/xma_context.h      |  6 ++++++
 src/xenia/apu/xma_context_new.cc | 12 +++++++++++-
 src/xenia/apu/xma_context_new.h  |  3 ++-
 src/xenia/apu/xma_decoder.cc     |  4 +++-
 src/xenia/base/cvar.h            |  2 +-
 5 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/xenia/apu/xma_context.h b/src/xenia/apu/xma_context.h
index d52f68897..d7dfa39c8 100644
--- a/src/xenia/apu/xma_context.h
+++ b/src/xenia/apu/xma_context.h
@@ -146,6 +146,12 @@ struct XMA_CONTEXT_DATA {
   const uint32_t GetCurrentInputBufferPacketCount() const {
     return GetInputBufferPacketCount(current_buffer);
   }
+  const bool IsStreamingContext() const {
+    return (input_buffer_0_packet_count | input_buffer_1_packet_count) == 1;
+  }
+  const bool IsConsumeOnlyContext() const {
+    return (input_buffer_0_packet_count | input_buffer_1_packet_count) == 0;
+  }
 };
 static_assert_size(XMA_CONTEXT_DATA, 64);
 
diff --git a/src/xenia/apu/xma_context_new.cc b/src/xenia/apu/xma_context_new.cc
index 4d7034c6c..6dad9704c 100644
--- a/src/xenia/apu/xma_context_new.cc
+++ b/src/xenia/apu/xma_context_new.cc
@@ -128,6 +128,15 @@ bool XmaContextNew::Work() {
 
   RingBuffer output_rb = PrepareOutputRingBuffer(&data);
 
+  if (data.IsConsumeOnlyContext()) {
+    Consume(&output_rb, &data);
+    if (data.output_buffer_read_offset == data.output_buffer_write_offset) {
+      Clear();
+    }
+    data.Store(context_ptr);
+    return true;
+  }
+
   const int32_t minimum_subframe_decode_count =
       (data.subframe_decode_count * 2) - 1;
 
@@ -257,7 +266,8 @@ void XmaContextNew::SwapInputBuffer(XMA_CONTEXT_DATA* data) {
   data->input_buffer_read_offset = kBitsPerPacketHeader;
 }
 
-void XmaContextNew::Consume(RingBuffer* output_rb, XMA_CONTEXT_DATA* data) {
+void XmaContextNew::Consume(RingBuffer* XE_RESTRICT output_rb,
+                            const XMA_CONTEXT_DATA* const XE_RESTRICT data) {
   if (!current_frame_remaining_subframes_) {
     return;
   }
diff --git a/src/xenia/apu/xma_context_new.h b/src/xenia/apu/xma_context_new.h
index 1d86c7af4..985b2ca9a 100644
--- a/src/xenia/apu/xma_context_new.h
+++ b/src/xenia/apu/xma_context_new.h
@@ -106,7 +106,8 @@ class XmaContextNew : public XmaContext {
   static uint32_t GetCurrentInputBufferSize(XMA_CONTEXT_DATA* data);
 
   void Decode(XMA_CONTEXT_DATA* data);
-  void Consume(RingBuffer* output_rb, XMA_CONTEXT_DATA* data);
+  void Consume(RingBuffer* XE_RESTRICT output_rb,
+               const XMA_CONTEXT_DATA* const XE_RESTRICT data);
 
   void UpdateLoopStatus(XMA_CONTEXT_DATA* data);
   int PrepareDecoder(int sample_rate, bool is_two_channel);
diff --git a/src/xenia/apu/xma_decoder.cc b/src/xenia/apu/xma_decoder.cc
index 07ff4c659..114885edd 100644
--- a/src/xenia/apu/xma_decoder.cc
+++ b/src/xenia/apu/xma_decoder.cc
@@ -54,7 +54,7 @@ extern "C" {
 DEFINE_bool(ffmpeg_verbose, false, "Verbose FFmpeg output (debug and above)",
             "APU");
 
-DEFINE_bool(use_new_decoder, false,
+DEFINE_bool(use_new_decoder, true,
             "Enables usage of new experimental XMA audio decoder.", "APU");
 
 DEFINE_bool(use_dedicated_xma_thread, true,
@@ -62,6 +62,8 @@ DEFINE_bool(use_dedicated_xma_thread, true,
             "better results, but decrease performance a bit.",
             "APU");
 
+UPDATE_from_bool(use_new_decoder, 2025, 12, 01, 23, false);
+
 namespace xe {
 namespace apu {
 
diff --git a/src/xenia/base/cvar.h b/src/xenia/base/cvar.h
index 6b139bda7..3c9581ba7 100644
--- a/src/xenia/base/cvar.h
+++ b/src/xenia/base/cvar.h
@@ -511,7 +511,7 @@ class IConfigVarUpdate {
   // If you're reviewing a pull request with a change here, check if 1) has been
   // done by the submitter before merging.
   static constexpr uint32_t kLastCommittedUpdateDate =
-      MakeConfigVarUpdateDate(2024, 9, 23, 9);
+      MakeConfigVarUpdateDate(2025, 12, 1, 23);
 
   virtual ~IConfigVarUpdate() = default;