diff --git a/src/sfizz/MidiState.cpp b/src/sfizz/MidiState.cpp
index 6e8ccac3..a5b40576 100644
--- a/src/sfizz/MidiState.cpp
+++ b/src/sfizz/MidiState.cpp
@@ -20,7 +20,7 @@ void sfz::MidiState::noteOnEvent(int delay, int noteNumber, float velocity) noex
 
     if (noteNumber >= 0 && noteNumber < 128) {
         lastNoteVelocities[noteNumber] = velocity;
-        noteOnTimes[noteNumber] = std::chrono::steady_clock::now();
+        noteOnTimes[noteNumber] = internalClock + static_cast<unsigned>(delay);
         activeNotes++;
     }
 
@@ -28,6 +28,7 @@ void sfz::MidiState::noteOnEvent(int delay, int noteNumber, float velocity) noex
 
 void sfz::MidiState::noteOffEvent(int delay, int noteNumber, float velocity) noexcept
 {
+    ASSERT(delay >= 0);
     ASSERT(noteNumber >= 0 && noteNumber <= 127);
     ASSERT(velocity >= 0.0 && velocity <= 1.0);
     UNUSED(velocity);
@@ -38,14 +39,30 @@ void sfz::MidiState::noteOffEvent(int delay, int noteNumber, float velocity) noe
 
 }
 
-float sfz::MidiState::getNoteDuration(int noteNumber) const
+void sfz::MidiState::setSampleRate(float sampleRate) noexcept
 {
-    ASSERT(noteNumber >= 0 && noteNumber <= 127);
+    this->sampleRate = sampleRate;
+    internalClock = 0;
+    absl::c_fill(noteOnTimes, 0);
+}
+
+void sfz::MidiState::advanceTime(int numSamples) noexcept
+{
+    internalClock += numSamples;
+}
+
+void sfz::MidiState::setSamplesPerBlock(int samplesPerBlock) noexcept
+{
+    this->samplesPerBlock = samplesPerBlock;
+}
+
+float sfz::MidiState::getNoteDuration(int noteNumber, int delay) const
+{
+    ASSERT(noteNumber >= 0 && noteNumber < 128);
 
     if (noteNumber >= 0 && noteNumber < 128) {
-        const auto noteOffTime = std::chrono::steady_clock::now();
-        const auto duration = std::chrono::duration_cast<std::chrono::duration<float>>(noteOffTime - noteOnTimes[noteNumber]);
-        return duration.count();
+        const unsigned timeInSamples = internalClock + static_cast<unsigned>(delay) - noteOnTimes[noteNumber];
+        return static_cast<float>(timeInSamples) / sampleRate;
     }
 
     return 0.0f;
@@ -95,6 +112,8 @@ void sfz::MidiState::reset(int delay) noexcept
 
     pitchBend = 0;
     activeNotes = 0;
+    internalClock = 0;
+    absl::c_fill(noteOnTimes, 0);
 }
 
 void sfz::MidiState::resetAllControllers(int delay) noexcept
diff --git a/src/sfizz/MidiState.h b/src/sfizz/MidiState.h
index 09c4ce78..d127d1de 100644
--- a/src/sfizz/MidiState.h
+++ b/src/sfizz/MidiState.h
@@ -5,7 +5,6 @@
 // If not, contact the sfizz maintainers at https://github.com/sfztools/sfizz
 
 #pragma once
-#include <chrono>
 #include <array>
 #include "CCMap.h"
 #include "Range.h"
@@ -42,13 +41,29 @@ public:
     int getActiveNotes() const noexcept { return activeNotes; }
 
     /**
-     * @brief Register a note off and get the note duration
+     * @brief Get the note duration since note on
      *
      * @param noteNumber
+     * @param delay
      * @return float
      */
-	float getNoteDuration(int noteNumber) const;
+	float getNoteDuration(int noteNumber, int delay = 0) const;
 
+    /**
+     * @brief Set the maximum size of the blocks for the callback. The actual
+     * size can be lower in each callback but should not be larger
+     * than this value.
+     *
+     * @param samplesPerBlock
+     */
+    void setSamplesPerBlock(int samplesPerBlock) noexcept;
+    /**
+     * @brief Set the sample rate. If you do not call it it is initialized
+     * to sfz::config::defaultSampleRate.
+     *
+     * @param sampleRate
+     */
+    void setSampleRate(float sampleRate) noexcept;
     /**
      * @brief Get the note on velocity for a given note
      *
@@ -79,6 +94,13 @@ public:
      */
     void ccEvent(int delay, int ccNumber, float ccValue) noexcept;
 
+    /**
+     * @brief Advances the internal clock of a given amount of samples.
+     * You should call this at each callback.
+     *
+     * @param numSamples the number of samples of clock advance
+     */
+    void advanceTime(int numSamples) noexcept;
     /**
      * @brief Get the CC value for CC number
      *
@@ -121,13 +143,13 @@ public:
 private:
     template<class T>
     using MidiNoteArray = std::array<T, 128>;
-    using NoteOnTime = std::chrono::steady_clock::time_point;
 	int activeNotes { 0 };
+
     /**
      * @brief Stores the note on times.
      *
      */
-	MidiNoteArray<NoteOnTime> noteOnTimes;
+	MidiNoteArray<unsigned> noteOnTimes {};
     /**
      * @brief Stores the velocity of the note ons for currently
      * depressed notes.
@@ -143,5 +165,8 @@ private:
      * Pitch bend status
      */
     int pitchBend { 0 };
+    double sampleRate { config::defaultSampleRate };
+    int samplesPerBlock { config::defaultSamplesPerBlock };
+    unsigned internalClock { 0 };
 };
 }
diff --git a/src/sfizz/Synth.cpp b/src/sfizz/Synth.cpp
index a3efca3e..6882030c 100644
--- a/src/sfizz/Synth.cpp
+++ b/src/sfizz/Synth.cpp
@@ -483,6 +483,7 @@ void sfz::Synth::setSamplesPerBlock(int samplesPerBlock) noexcept
     this->tempMixNodeBuffer.resize(samplesPerBlock);
     for (auto& voice : voices)
         voice->setSamplesPerBlock(samplesPerBlock);
+    resources.midiState.setSamplesPerBlock(samplesPerBlock);
 
     for (auto& bus : effectBuses) {
         if (bus)
@@ -503,6 +504,7 @@ void sfz::Synth::setSampleRate(float sampleRate) noexcept
 
     resources.filterPool.setSampleRate(sampleRate);
     resources.eqPool.setSampleRate(sampleRate);
+    resources.midiState.setSampleRate(sampleRate);
 
     for (auto& bus : effectBuses) {
         if (bus)
@@ -525,6 +527,8 @@ void sfz::Synth::renderBlock(AudioSpan<float> buffer) noexcept
     auto temp = AudioSpan<float>(tempBuffer).first(numFrames);
     auto tempMixNode = AudioSpan<float>(tempMixNodeBuffer).first(numFrames);
 
+    resources.midiState.advanceTime(buffer.getNumFrames());
+
     CallbackBreakdown callbackBreakdown;
 
     { // Prepare the effect inputs. They are mixes of per-region outputs.
diff --git a/tests/RegionValueComputationsT.cpp b/tests/RegionValueComputationsT.cpp
index 31566e76..0f760b06 100644
--- a/tests/RegionValueComputationsT.cpp
+++ b/tests/RegionValueComputationsT.cpp
@@ -262,20 +262,21 @@ TEST_CASE("[Region] Velocity bug for extreme values - negative veltrack")
 TEST_CASE("[Region] rt_decay")
 {
     sfz::MidiState midiState;
+    midiState.setSampleRate(1000);
     sfz::Region region { midiState };
     region.parseOpcode({ "sample", "*sine" });
     region.parseOpcode({ "trigger", "release" });
     region.parseOpcode({ "rt_decay", "10" });
     midiState.noteOnEvent(0, 64, 64_norm);
-    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+    midiState.advanceTime(100);
     REQUIRE( region.getBaseVolumedB(64) == Approx(sfz::Default::volume - 1.0f).margin(0.1) );
     region.parseOpcode({ "rt_decay", "20" });
     midiState.noteOnEvent(0, 64, 64_norm);
-    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+    midiState.advanceTime(100);
     REQUIRE( region.getBaseVolumedB(64) == Approx(sfz::Default::volume - 2.0f).margin(0.1) );
     region.parseOpcode({ "trigger", "attack" });
     midiState.noteOnEvent(0, 64, 64_norm);
-    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+    midiState.advanceTime(100);
     REQUIRE( region.getBaseVolumedB(64) == Approx(sfz::Default::volume).margin(0.1) );
 }