From 25a1d2b50842e767ddefb6447ccda0793cae73a4 Mon Sep 17 00:00:00 2001
From: John <john@eden-emu.dev>
Date: Sun, 28 Dec 2025 06:21:30 +0100
Subject: [PATCH] EdenEmulator-13-39-06.patch

Credit: Forrest Mark X
---
 .../renderer/command/command_buffer.cpp       | 36 +++++++++++------
 .../renderer/command/command_generator.cpp    | 40 ++++++++++++-------
 2 files changed, 48 insertions(+), 28 deletions(-)

diff --git a/src/audio_core/renderer/command/command_buffer.cpp b/src/audio_core/renderer/command/command_buffer.cpp
index 804aba438d..8ee00e873d 100644
--- a/src/audio_core/renderer/command/command_buffer.cpp
+++ b/src/audio_core/renderer/command/command_buffer.cpp
@@ -271,24 +271,34 @@ void CommandBuffer::GenerateBiquadFilterCommand(const s32 node_id, EffectInfoBas
     const auto state{reinterpret_cast<VoiceState::BiquadFilterState*>(
         effect_info.GetStateBuffer() + channel * sizeof(VoiceState::BiquadFilterState))};
 
+    // This is a simple fix for Metroid Prime Remastered as it can throw the emulator both a v1 and v2 parameter. I wasn't sure a proper way to use this so did a simple heuristic check.
+    // This should mostly work as since the binary data is misaligned state and channel_count should almost always be a corrupted value
+    bool is_version2_active = false;
     if (behavior->IsEffectInfoVersion2Supported()) {
-        const auto& p{
+        const auto& p2{
             *reinterpret_cast<BiquadFilterInfo::ParameterVersion2*>(effect_info.GetParameter())};
 
-        if (!IsChannelCountValid(p.channel_count) || channel < 0 || channel >= p.channel_count) {
-            return;
-        }
+        if (p2.state <= EffectInfoBase::ParameterState::Updated &&
+            p2.channel_count > 0) {
+            is_version2_active = true;
 
-        cmd.input = buffer_offset + p.inputs[channel];
-        cmd.output = buffer_offset + p.outputs[channel];
+            if (!IsChannelCountValid(p2.channel_count) || channel < 0 || channel >= p2.channel_count) {
+                return;
+            }
 
-        // Convert float coefficients to Q2.14 fixed-point as expected by the legacy DSP path.
-        cmd.biquad.b[0] = ToQ14Clamped(p.b[0]);
-        cmd.biquad.b[1] = ToQ14Clamped(p.b[1]);
-        cmd.biquad.b[2] = ToQ14Clamped(p.b[2]);
-        cmd.biquad.a[0] = ToQ14Clamped(p.a[0]);
-        cmd.biquad.a[1] = ToQ14Clamped(p.a[1]);
-    } else {
+            cmd.input = buffer_offset + p2.inputs[channel];
+            cmd.output = buffer_offset + p2.outputs[channel];
+
+            // Convert float coefficients to Q2.14 fixed-point as expected by the legacy DSP path.
+            cmd.biquad.b[0] = ToQ14Clamped(p2.b[0]);
+            cmd.biquad.b[1] = ToQ14Clamped(p2.b[1]);
+            cmd.biquad.b[2] = ToQ14Clamped(p2.b[2]);
+            cmd.biquad.a[0] = ToQ14Clamped(p2.a[0]);
+            cmd.biquad.a[1] = ToQ14Clamped(p2.a[1]);
+        }
+    }
+
+    if (!is_version2_active) {
         const auto& p{
             *reinterpret_cast<BiquadFilterInfo::ParameterVersion1*>(effect_info.GetParameter())};
 
diff --git a/src/audio_core/renderer/command/command_generator.cpp b/src/audio_core/renderer/command/command_generator.cpp
index bec6abbaf9..b150d48c75 100644
--- a/src/audio_core/renderer/command/command_generator.cpp
+++ b/src/audio_core/renderer/command/command_generator.cpp
@@ -367,23 +367,33 @@ void CommandGenerator::GenerateBiquadFilterEffectCommand(const s16 buffer_offset
     EffectInfoBase::ParameterState param_state{};
     s8 channel_count = 0;
 
-    if (render_context.behavior->IsEffectInfoVersion2Supported()) {
-        const auto* parameter =
-            reinterpret_cast<const BiquadFilterInfo::ParameterVersion2*>(effect_info.GetParameter());
-        if (!parameter) {
-            LOG_ERROR(Service_Audio, "Biquad filter parameter is null");
-            return;
+    const void* raw_data = effect_info.GetParameter();
+    if (!raw_data) {
+        LOG_ERROR(Service_Audio, "Biquad filter parameter is null");
+        return;
+    }
+
+    // This is a simple fix for Metroid Prime Remastered as it can throw the emulator both a v1 and v2 parameter. I wasn't sure a proper way to use this so did a simple heuristic check.
+    // This should mostly work as since the binary data is misaligned state and channel_count should almost always be a corrupted value
+    bool is_version2_active = false;
+    if (render_context.behavior->IsEffectInfoVersion2Supported() ) {
+        const auto* parameter_v2 =
+            reinterpret_cast<const BiquadFilterInfo::ParameterVersion2*>(raw_data);
+
+        if (parameter_v2->state <= EffectInfoBase::ParameterState::Updated &&
+            parameter_v2->channel_count > 0) {
+            is_version2_active = true;
+
+            state = parameter_v2->state;
+            channel_count = parameter_v2->channel_count;
         }
-        param_state = parameter->state;
-        channel_count = parameter->channel_count;
-    } else {
+    }
+
+    if (!is_version2_active) {
         const auto* parameter =
-            reinterpret_cast<const BiquadFilterInfo::ParameterVersion1*>(effect_info.GetParameter());
-        if (!parameter) {
-            LOG_ERROR(Service_Audio, "Biquad filter parameter is null");
-            return;
-        }
-        param_state = parameter->state;
+            reinterpret_cast<const BiquadFilterInfo::ParameterVersion1*>(raw_data);
+
+        state = parameter->state;
         channel_count = parameter->channel_count;
     }