diff --git a/composeApp/src/androidMain/kotlin/mg/dot/feufaro/midi/MidiWriterKotlin.kt b/composeApp/src/androidMain/kotlin/mg/dot/feufaro/midi/MidiWriterKotlin.kt
index cbdabe7..f38d731 100644
--- a/composeApp/src/androidMain/kotlin/mg/dot/feufaro/midi/MidiWriterKotlin.kt
+++ b/composeApp/src/androidMain/kotlin/mg/dot/feufaro/midi/MidiWriterKotlin.kt
@@ -20,7 +20,7 @@ actual class MidiWriterKotlin actual constructor(private val fileRepository: Fil
             finalNote -= 12
         }
         if (lastPitch.size > voiceNumber && lastPitch[voiceNumber] > 0) {
-            sequence.addNote(channel, lastPitch[voiceNumber], tick)
+            sequence.addSequence(channel, lastPitch[voiceNumber], tick)
         }
         var finalVelocity = velocity
         var midiNote = finalNote
@@ -28,7 +28,7 @@ actual class MidiWriterKotlin actual constructor(private val fileRepository: Fil
             midiNote = 40
             finalVelocity = 0
         }
-        sequence.addNote(channel, midiNote, tick, 90, finalVelocity)
+        sequence.addSequence(channel, midiNote, tick, 90, finalVelocity)
 
         while(lastPitch.size <= voiceNumber) {
             lastPitch.add(0)
@@ -44,9 +44,7 @@ actual class MidiWriterKotlin actual constructor(private val fileRepository: Fil
         }
     }
     actual fun addMetaMessage(type: Int, tick: Int, nbData: Int, metaByteString: String) {
-        /*val byteArray = metaByteString.toByteArray()
-        val metaMessage = MetaMessage(type, byteArray, nbData)
-        track.add(MidiEvent(metaMessage, tick.toLong()))*/
+        sequence.addMeta( type, tick, nbData, metaByteString)
     }
     actual fun process(pitches: List<MidiPitch>) {
         val lastTick = 0
diff --git a/composeApp/src/commonMain/kotlin/mg/dot/feufaro/midi/MidiSequence.kt b/composeApp/src/commonMain/kotlin/mg/dot/feufaro/midi/MidiSequence.kt
index 8555fbc..fe8e8d7 100644
--- a/composeApp/src/commonMain/kotlin/mg/dot/feufaro/midi/MidiSequence.kt
+++ b/composeApp/src/commonMain/kotlin/mg/dot/feufaro/midi/MidiSequence.kt
@@ -5,16 +5,11 @@ class MidiSequence(val resolution: Int = 60) {
     // Une liste de pistes, où chaque piste est une liste d'octets (ByteArray)
     val tracks = mutableListOf<MutableList<Byte>>()
     val out: MutableList<Byte> = mutableListOf<Byte>()
-    private var lastTick = mutableListOf<Long>()
+    private var lastTick = 0L
 
     fun getDeltaAndSync(channel: Int, currentTick: Long): Long {
-        // Si le canal demandé dépasse la taille actuelle, on remplit de 0L
-        while (lastTick.size <= channel) {
-            lastTick.add(0L)
-        }
-
-        val delta = currentTick - lastTick[channel]
-        lastTick[channel] = currentTick
+        val delta = currentTick - lastTick
+        lastTick = currentTick
         return delta
     }
     fun createTrack(): MutableList<Byte> {
@@ -44,15 +39,11 @@ class MidiSequence(val resolution: Int = 60) {
         }
     }
 
-    fun addNote(channel: Int, pitch: Int, currentTick: Long, type: Int = 80, finalVelocity: Int = 80) {
-        while (tracks.size <= channel) {
-            tracks.add(mutableListOf<Byte>(0))
-        }
-
-        val myTrack = tracks[channel]
+    fun addSequence(channel: Int, pitch: Int, currentTick: Long, type: Int = 80, finalVelocity: Int = 100) {
+        val myTrack = tracks[0]
         myTrack.addNote(channel, pitch, currentTick, type, finalVelocity)
     }
-    fun MutableList<Byte>.addNote(channel: Int, pitch: Int, currentTick: Long, type: Int = 80, finalVelocity: Int = 80) {
+    fun MutableList<Byte>.addNote(channel: Int, pitch: Int, currentTick: Long, type: Int = 80, finalVelocity: Int = 100) {
         // Calcul du Delta-Time
         val delta = getDeltaAndSync(channel, currentTick)
 
@@ -92,7 +83,7 @@ class MidiSequence(val resolution: Int = 60) {
         out.write16Bit(1)
 
         // 4. Nombre de pistes (16 bits)
-        out.write16Bit(trackCount) // trackCount = 4 is wrong, why?
+        out.write16Bit(trackCount) 
 
         // 5. Division / Résolution (16 bits)
         // Ticks par noire (votre variable 'resolution')
@@ -125,4 +116,19 @@ class MidiSequence(val resolution: Int = 60) {
             writeTrackChunk( track)
         }
     }
+    fun addMeta(type: Int, tick: Int, nbData: Int, metaByteString: String) {
+        val data = metaByteString.encodeToByteArray()
+        if (tracks.isEmpty()) {
+            tracks.add(mutableListOf<Byte>(0))
+        }
+        val outTrack = tracks[0]
+        // Un Meta Message commence toujours par FF, puis le type, puis la longueur
+        outTrack.add(0x00.toByte())        // Status byte
+        outTrack.add(0xFF.toByte())        // Status byte
+        outTrack.add(type.toByte())        // Meta-event type
+        outTrack.addAll(nbData.toLong().toVLQList())
+        // Ajout des données
+        outTrack.addAll(data.toList().take(nbData))
+
+    }
 }
diff --git a/composeApp/src/desktopMain/kotlin/mg/dot/feufaro/midi/MidiWriterKotlin.kt b/composeApp/src/desktopMain/kotlin/mg/dot/feufaro/midi/MidiWriterKotlin.kt
index 74c7302..21e39a7 100644
--- a/composeApp/src/desktopMain/kotlin/mg/dot/feufaro/midi/MidiWriterKotlin.kt
+++ b/composeApp/src/desktopMain/kotlin/mg/dot/feufaro/midi/MidiWriterKotlin.kt
@@ -10,7 +10,6 @@ actual class MidiWriterKotlin actual constructor(private val fileRepository: Fil
     private val sequence = Sequence(Sequence.PPQ, 60)
     private val track    = sequence.createTrack()
     private var tick: Long = 0
-    //private var nextTick: MidiPitch<Int> = mutableListOf()
     private var nextTick: MutableList<MidiPitch> = mutableListOf()
     private val noteOn   = ShortMessage()
     private val noteOff = ShortMessage()