From eb5a25fe0a3d1e862a22c006486d0c0197565e7f Mon Sep 17 00:00:00 2001
From: Victor Giers <mail@victorgiers.com>
Date: Mon, 13 Jul 2026 05:29:26 +0200
Subject: [PATCH] Improve Ableton automation export for filters and add
 dedicated filter building function

---
 src/lib/exporters/ableton/automation.ts |  4 +-
 src/lib/exporters/ableton/builders.ts   | 64 +++++++++++++++++--------
 2 files changed, 46 insertions(+), 22 deletions(-)

diff --git a/src/lib/exporters/ableton/automation.ts b/src/lib/exporters/ableton/automation.ts
index 25936f2..dc659c3 100644
--- a/src/lib/exporters/ableton/automation.ts
+++ b/src/lib/exporters/ableton/automation.ts
@@ -47,9 +47,9 @@ export function convertFaderValue(
     case FaderParam.PTC:
       return (value - 0.5) * 10;
     case FaderParam.LPF:
-      return filterFreqFromNormalized(value * 0.9);
+      return 20 + value * 0.9 * 115;
     case FaderParam.HPF:
-      return filterFreqFromNormalized(value * 0.7);
+      return 20 + value * 0.7 * 115;
     case FaderParam.FX:
       return value;
     case FaderParam.ATK:
diff --git a/src/lib/exporters/ableton/builders.ts b/src/lib/exporters/ableton/builders.ts
index 7a89d05..63e1a42 100644
--- a/src/lib/exporters/ableton/builders.ts
+++ b/src/lib/exporters/ableton/builders.ts
@@ -122,6 +122,25 @@ function findSimplers(node: any, result: any[] = []): any[] {
   return result;
 }
 
+function findAutoFilters(node: any, result: any[] = []): any[] {
+  if (Array.isArray(node)) {
+    node.forEach((item) => {
+      findAutoFilters(item, result);
+    });
+    return result;
+  }
+  if (!node || typeof node !== 'object') {
+    return result;
+  }
+  if (node.AutoFilter) {
+    result.push(node.AutoFilter);
+  }
+  Object.values(node).forEach((value) => {
+    findAutoFilters(value, result);
+  });
+  return result;
+}
+
 function addTarget(
   targets: AbletonAutomationTargets,
   parameter: FaderParam,
@@ -157,13 +176,17 @@ function trackAutomationTargets(midiTrack: any, includeArrangementMixer: boolean
   findSimplers(midiTrack.DeviceChain.DeviceChain.Devices).forEach((simpler) => {
     addTarget(targets, FaderParam.PTC, targetFor(simpler.Pitch.TransposeKey));
     addTarget(targets, FaderParam.TUNE, targetFor(simpler.Pitch.TransposeFine));
-    addTarget(targets, FaderParam.LPF, targetFor(simpler.Filter.Slot.Value.SimplerFilter.Freq));
-    addTarget(targets, FaderParam.HPF, targetFor(simpler.Filter.Slot.Value.SimplerFilter.Freq));
     addTarget(targets, FaderParam.ATK, targetFor(simpler.VolumeAndPan.Envelope.AttackTime));
     addTarget(targets, FaderParam.REL, targetFor(simpler.VolumeAndPan.Envelope.ReleaseTime));
     addTarget(targets, FaderParam.MOD, targetFor(simpler.Pitch.PitchLfoAmount));
   });
 
+  findAutoFilters(midiTrack.DeviceChain.DeviceChain.Devices).forEach((filter) => {
+    const parameter =
+      Number(filter.FilterType.Manual['@Value']) === 1 ? FaderParam.HPF : FaderParam.LPF;
+    addTarget(targets, parameter, targetFor(filter.Cutoff));
+  });
+
   return targets;
 }
 
@@ -395,24 +418,6 @@ async function buildSimplerDevice(koTrack: AblTrack, abletonVersion: AbletonVers
     device.Lfo.Slot.Value.SimplerLfo.RateType.Manual['@Value'] = 1; // tempo synced 1/16
   }
 
-  if (koTrack.faderParams[FaderParam.LPF] !== -1 && koTrack.faderParams[FaderParam.LPF] !== 1) {
-    device.Filter.IsOn.Manual['@Value'] = 'true';
-    device.Filter.Slot.Value.SimplerFilter.Type.Manual['@Value'] = 0; // Low Pass
-    device.Filter.Slot.Value.SimplerFilter.Slope.Manual['@Value'] = 'true'; // 24db/oct
-    device.Filter.Slot.Value.SimplerFilter.Freq.Manual['@Value'] = filterFreqFromNormalized(
-      koTrack.faderParams[FaderParam.LPF] * 0.9, // lowering max freq to match KO behavior
-    );
-  }
-
-  if (koTrack.faderParams[FaderParam.HPF] !== -1 && koTrack.faderParams[FaderParam.HPF] !== 0) {
-    device.Filter.IsOn.Manual['@Value'] = 'true';
-    device.Filter.Slot.Value.SimplerFilter.Type.Manual['@Value'] = 1; // High Pass
-    device.Filter.Slot.Value.SimplerFilter.Slope.Manual['@Value'] = 'false'; // 12db/oct
-    device.Filter.Slot.Value.SimplerFilter.Freq.Manual['@Value'] = filterFreqFromNormalized(
-      koTrack.faderParams[FaderParam.HPF] * 0.7, // lowering max freq to match KO behavior
-    );
-  }
-
   // TODO: add bandpass filter
 
   if (koTrack.timeStretch === 'bars') {
@@ -471,6 +476,25 @@ async function buildSimplerDevice(koTrack: AblTrack, abletonVersion: AbletonVers
   };
 }
 
+async function buildFaderFilterDevice(
+  parameter: FaderParam.LPF | FaderParam.HPF,
+  value: number,
+  abletonVersion: AbletonVersion,
+) {
+  const filterTemplate = await loadTemplate<ALSFilter>('effectFilter', abletonVersion);
+  const filter = structuredClone(filterTemplate.AutoFilter);
+  const highPass = parameter === FaderParam.HPF;
+  filter.LastPresetRef.Value = {};
+  filter.UserName['@Value'] = highPass ? 'EP HPF' : 'EP LPF';
+  filter.FilterType.Manual['@Value'] = highPass ? 1 : 0;
+  filter.LegacyFilterType.Manual['@Value'] = highPass ? 1 : 0;
+  filter.Slope.Manual['@Value'] = highPass ? 'false' : 'true';
+  filter.Cutoff.Manual['@Value'] = highPass
+    ? 20 + value * 0.7 * 115
+    : 20 + value * 0.9 * 115;
+  return { AutoFilter: filter };
+}
+
 async function buildDrumRackDevice(koTrack: AblTrack, abletonVersion: AbletonVersion) {
   const [drumRackTemplate, drumBranchTemplate] = await Promise.all([
     loadTemplate<ALSDrumRack>('drumRack', abletonVersion),