fix(audio): Refactor ParameterVersion2 to match ParameterVersion1 structure

- Change ParameterVersion2 to use fixed-point coefficients (s16) instead of float
- Replace enable bool with ParameterState enum for consistency
- Update validation logic to use state field instead of enable
- Add state validation in Update() method
- Update UpdateForCommandGeneration() to handle both versions

Signed-off-by: Zephyron <zephyron@citron-emu.org>

src/audio_core/renderer/effect/biquad_filter.cpp

@@ -1,6 +1,9 @@
 // SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
+// SPDX-FileCopyrightText: Copyright 2025 citron Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#include <algorithm>
+
 #include "audio_core/renderer/effect/biquad_filter.h"
 
 namespace AudioCore::Renderer {
@@ -11,9 +14,45 @@ void BiquadFilterInfo::Update(BehaviorInfo::ErrorInfo& error_info,
     auto params{reinterpret_cast<ParameterVersion1*>(parameter.data())};
 
     std::memcpy(params, in_specific, sizeof(ParameterVersion1));
+
+    // Check for corrupted parameters - if detected, disable the effect to prevent audio issues
+    bool parameters_valid = true;
+
+    // Validate channel_count
+    if (params->channel_count < 0 || static_cast<u32>(params->channel_count) > MaxChannels) {
+        LOG_WARNING(Service_Audio, "BiquadFilterInfo: Invalid channel_count {}, disabling effect",
+                    params->channel_count);
+        parameters_valid = false;
+    }
+
+    // Validate parameter state
+    if (static_cast<u8>(params->state) > static_cast<u8>(EffectInfoBase::ParameterState::Updated)) {
+        LOG_WARNING(Service_Audio, "BiquadFilterInfo: Invalid parameter state {}, disabling effect",
+                    static_cast<u8>(params->state));
+        parameters_valid = false;
+    }
+
+    // Validate input/output buffer indices
+    for (s8 i = 0; static_cast<u32>(i) < MaxChannels && parameters_valid; i++) {
+        // Negative values are allowed (indicate unused channels), but check for out-of-range values
+        if (params->inputs[i] < -1 || params->inputs[i] >= static_cast<s8>(MaxChannels * 2)) {
+            LOG_WARNING(Service_Audio, "BiquadFilterInfo: Invalid input buffer index {} for channel {}, disabling effect",
+                        params->inputs[i], i);
+            parameters_valid = false;
+            break;
+        }
+        if (params->outputs[i] < -1 || params->outputs[i] >= static_cast<s8>(MaxChannels * 2)) {
+            LOG_WARNING(Service_Audio, "BiquadFilterInfo: Invalid output buffer index {} for channel {}, disabling effect",
+                        params->outputs[i], i);
+            parameters_valid = false;
+            break;
+        }
+    }
+
     mix_id = in_params.mix_id;
     process_order = in_params.process_order;
-    enabled = in_params.enabled;
+    // Disable effect if parameters are corrupted to prevent audio issues
+    enabled = in_params.enabled && parameters_valid;
 
     error_info.error_code = ResultSuccess;
     error_info.address = CpuAddr(0);
@@ -25,9 +64,48 @@ void BiquadFilterInfo::Update(BehaviorInfo::ErrorInfo& error_info,
     auto params{reinterpret_cast<ParameterVersion2*>(parameter.data())};
 
     std::memcpy(params, in_specific, sizeof(ParameterVersion2));
+
+    // Check for corrupted parameters - if detected, disable the effect to prevent audio issues
+    bool parameters_valid = true;
+
+    // Validate channel_count
+    if (params->channel_count < 0 || static_cast<u32>(params->channel_count) > MaxChannels) {
+        LOG_WARNING(Service_Audio, "BiquadFilterInfo: Invalid channel_count {}, disabling effect",
+                    params->channel_count);
+        parameters_valid = false;
+    }
+
+    // Validate input/output buffer indices only for active channels
+    const s8 active_channels = parameters_valid ? params->channel_count : 0;
+    for (s8 i = 0; static_cast<u32>(i) < MaxChannels && i < active_channels && parameters_valid; i++) {
+        // Negative values are allowed (indicate unused channels), but check for out-of-range values
+        if (params->inputs[i] < -1 || params->inputs[i] >= static_cast<s8>(MaxChannels * 2)) {
+            LOG_WARNING(Service_Audio, "BiquadFilterInfo: Invalid input buffer index {} for channel {}, disabling effect",
+                        params->inputs[i], i);
+            parameters_valid = false;
+            break;
+        }
+        if (params->outputs[i] < -1 || params->outputs[i] >= static_cast<s8>(MaxChannels * 2)) {
+            LOG_WARNING(Service_Audio, "BiquadFilterInfo: Invalid output buffer index {} for channel {}, disabling effect",
+                        params->outputs[i], i);
+            parameters_valid = false;
+            break;
+        }
+    }
+
+    // Validate parameter state
+    if (static_cast<u8>(params->state) > static_cast<u8>(EffectInfoBase::ParameterState::Updated)) {
+        LOG_WARNING(Service_Audio, "BiquadFilterInfo: Invalid parameter state {}, disabling effect",
+                    static_cast<u8>(params->state));
+        parameters_valid = false;
+    }
+
     mix_id = in_params.mix_id;
     process_order = in_params.process_order;
-    enabled = in_params.enabled;
+    // ParameterVersion2 uses state field similar to v1
+    // Effect is enabled if in_params.enabled, parameters are valid, and state is within valid range
+    enabled = in_params.enabled && parameters_valid &&
+              static_cast<u8>(params->state) <= static_cast<u8>(EffectInfoBase::ParameterState::Updated);
 
     error_info.error_code = ResultSuccess;
     error_info.address = CpuAddr(0);
@@ -40,8 +118,12 @@ void BiquadFilterInfo::UpdateForCommandGeneration() {
         usage_state = UsageState::Disabled;
     }
 
+    // Both v1 and v2 have the same structure with state field, so we can update using either cast
     auto params{reinterpret_cast<ParameterVersion1*>(parameter.data())};
+    if (params->state == ParameterState::Initialized ||
+        params->state == ParameterState::Updating) {
         params->state = ParameterState::Updated;
+    }
 }
 
 void BiquadFilterInfo::InitializeResultState(EffectResultState& result_state) {}