[audio] correct biquad filter v2 parameters (#3142)

We had the same struct for v1 and v2 - this was tested only with MP4, should output correct sounds now and boot it.

Co-authored-by: MaranBr <maranbr@outlook.com>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3142
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: crueter <crueter@eden-emu.dev>
Co-authored-by: Maufeat <sahyno1996@gmail.com>
Co-committed-by: Maufeat <sahyno1996@gmail.com>

2 files changed, 92 insertions, 18 deletions

diff --git a/src/audio_core/renderer/command/command_buffer.cpp b/src/audio_core/renderer/command/command_buffer.cpp
index a0a574fc64..804aba438d 100644
--- a/src/audio_core/renderer/command/command_buffer.cpp
+++ b/src/audio_core/renderer/command/command_buffer.cpp
@@ -21,6 +21,15 @@
 
 namespace AudioCore::Renderer {
 
+namespace {
+constexpr f32 BiquadParameterFixedScaleQ14 = 16384.0f; // 1 << 14
+
+[[nodiscard]] inline s16 ToQ14Clamped(f32 v) {
+    const f32 scaled = std::clamp(v * BiquadParameterFixedScaleQ14, -32768.0f, 32767.0f);
+    return static_cast<s16>(scaled);
+}
+} // namespace
+
 template <typename T, CommandId Id>
 T& CommandBuffer::GenerateStart(const s32 node_id) {
     if (size + sizeof(T) >= command_list.size_bytes()) {
@@ -259,18 +268,42 @@ void CommandBuffer::GenerateBiquadFilterCommand(const s32 node_id, EffectInfoBas
                                                 const bool use_float_processing) {
     auto& cmd{GenerateStart<BiquadFilterCommand, CommandId::BiquadFilter>(node_id)};
 
-    const auto& parameter{
-        *reinterpret_cast<BiquadFilterInfo::ParameterVersion1*>(effect_info.GetParameter())};
     const auto state{reinterpret_cast<VoiceState::BiquadFilterState*>(
         effect_info.GetStateBuffer() + channel * sizeof(VoiceState::BiquadFilterState))};
 
-    cmd.input = buffer_offset + parameter.inputs[channel];
-    cmd.output = buffer_offset + parameter.outputs[channel];
+    if (behavior->IsEffectInfoVersion2Supported()) {
+        const auto& p{
+            *reinterpret_cast<BiquadFilterInfo::ParameterVersion2*>(effect_info.GetParameter())};
 
-    cmd.biquad.b = parameter.b;
-    cmd.biquad.a = parameter.a;
+        if (!IsChannelCountValid(p.channel_count) || channel < 0 || channel >= p.channel_count) {
+            return;
+        }
+
+        cmd.input = buffer_offset + p.inputs[channel];
+        cmd.output = buffer_offset + p.outputs[channel];
+
+        // 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 {
+        const auto& p{
+            *reinterpret_cast<BiquadFilterInfo::ParameterVersion1*>(effect_info.GetParameter())};
 
-    // Effects use legacy fixed-point format
+        if (!IsChannelCountValid(p.channel_count) || channel < 0 || channel >= p.channel_count) {
+            return;
+        }
+
+        cmd.input = buffer_offset + p.inputs[channel];
+        cmd.output = buffer_offset + p.outputs[channel];
+
+        cmd.biquad.b = p.b;
+        cmd.biquad.a = p.a;
+    }
+
+    // Effects always use the fixed-point coefficient path on the DSP.
     cmd.use_float_coefficients = false;
 
     cmd.state = memory_pool->Translate(CpuAddr(state),
@@ -595,6 +628,15 @@ void CommandBuffer::GenerateCopyMixBufferCommand(const s32 node_id, EffectInfoBa
                                                  const s16 buffer_offset, const s8 channel) {
     auto& cmd{GenerateStart<CopyMixBufferCommand, CommandId::CopyMixBuffer>(node_id)};
 
+    if (behavior->IsEffectInfoVersion2Supported()) {
+        const auto& parameter_v2{
+            *reinterpret_cast<BiquadFilterInfo::ParameterVersion2*>(effect_info.GetParameter())};
+        cmd.input_index = buffer_offset + parameter_v2.inputs[channel];
+        cmd.output_index = buffer_offset + parameter_v2.outputs[channel];
+        GenerateEnd<CopyMixBufferCommand>(cmd);
+        return;
+    }
+
     const auto& parameter{
         *reinterpret_cast<BiquadFilterInfo::ParameterVersion1*>(effect_info.GetParameter())};
     cmd.input_index = buffer_offset + parameter.inputs[channel];
diff --git a/src/audio_core/renderer/command/command_generator.cpp b/src/audio_core/renderer/command/command_generator.cpp
index f97db5899e..bec6abbaf9 100644
--- a/src/audio_core/renderer/command/command_generator.cpp
+++ b/src/audio_core/renderer/command/command_generator.cpp
@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -361,12 +364,37 @@ void CommandGenerator::GenerateAuxCommand(const s16 buffer_offset, EffectInfoBas
 void CommandGenerator::GenerateBiquadFilterEffectCommand(const s16 buffer_offset,
                                                          EffectInfoBase& effect_info,
                                                          const s32 node_id) {
-    const auto& parameter{
-        *reinterpret_cast<BiquadFilterInfo::ParameterVersion1*>(effect_info.GetParameter())};
+    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;
+        }
+        param_state = parameter->state;
+        channel_count = parameter->channel_count;
+    } else {
+        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;
+        channel_count = parameter->channel_count;
+    }
+
+    if (channel_count <= 0) {
+        return;
+    }
+
     if (effect_info.IsEnabled()) {
         bool needs_init{false};
 
-        switch (parameter.state) {
+        switch (param_state) {
         case EffectInfoBase::ParameterState::Initialized:
             needs_init = true;
             break;
@@ -375,22 +403,26 @@ void CommandGenerator::GenerateBiquadFilterEffectCommand(const s16 buffer_offset
             if (render_context.behavior->IsBiquadFilterEffectStateClearBugFixed()) {
                 needs_init = false;
             } else {
-                needs_init = parameter.state == EffectInfoBase::ParameterState::Updating;
+                needs_init = param_state == EffectInfoBase::ParameterState::Updating;
             }
             break;
         default:
-            LOG_ERROR(Service_Audio, "Invalid biquad parameter state {}",
-                      static_cast<u32>(parameter.state));
+            LOG_ERROR(Service_Audio,
+                      "Invalid biquad parameter state {}, treating as uninitialized",
+                      static_cast<u32>(param_state));
+            needs_init = true;
             break;
         }
 
-        for (s8 channel = 0; channel < parameter.channel_count; channel++) {
-            command_buffer.GenerateBiquadFilterCommand(
-                node_id, effect_info, buffer_offset, channel, needs_init,
-                render_context.behavior->UseBiquadFilterFloatProcessing());
+        const bool use_float_processing =
+            render_context.behavior->UseBiquadFilterFloatProcessing();
+
+        for (s8 channel = 0; channel < channel_count; channel++) {
+            command_buffer.GenerateBiquadFilterCommand(node_id, effect_info, buffer_offset, channel,
+                                                       needs_init, use_float_processing);
         }
     } else {
-        for (s8 channel = 0; channel < parameter.channel_count; channel++) {
+        for (s8 channel = 0; channel < channel_count; channel++) {
             command_buffer.GenerateCopyMixBufferCommand(node_id, effect_info, buffer_offset,
                                                         channel);
         }