From bb9a4123b0b819ab27a09a25cad95d80d18395bb Mon Sep 17 00:00:00 2001
From: rdkartono <rdkartono@galva.co.id>
Date: Thu, 31 Jul 2025 12:06:02 +0700
Subject: [PATCH] Commit 31/07/2025

---
 src/Main.kt                      |  1 +
 src/somecodes/Codes.kt           | 25 ++++++++++++++++++
 src/zello/Event_OnStreamStart.kt | 44 ++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)

diff --git a/src/Main.kt b/src/Main.kt
index cf2673f..02f618a 100644
--- a/src/Main.kt
+++ b/src/Main.kt
@@ -5,6 +5,7 @@ import zello.ZelloEvent
 //TIP To <b>Run</b> code, press <shortcut actionId="Run"/> or
 // click the <icon src="AllIcons.Actions.Execute"/> icon in the gutter.
 fun main() {
+
     val z = ZelloClient.fromConsumerZello()
     z.Start(object : ZelloEvent {
         override fun onChannelStatus(
diff --git a/src/somecodes/Codes.kt b/src/somecodes/Codes.kt
index 2040bc2..715a027 100644
--- a/src/somecodes/Codes.kt
+++ b/src/somecodes/Codes.kt
@@ -1,10 +1,35 @@
 package somecodes
 
+@Suppress("unused")
 class Codes {
 
     companion object{
         fun ValidString(s : String?) : Boolean {
             return s != null && s.isNotEmpty() && s.isNotBlank()
         }
+
+        /**
+         * Codec header for Zello audio packet is base64 encoded string from {samplingrate (16 Little Endian), frames_per_packet, frame_size_ms}
+         * @param samplingrate Sampling rate in Hz (e.g., 8000, 16000, 32000, etc.)
+         * @param frames_per_packet Number of frames per packet (usually 1 or 2)
+         * @param frame_size_ms Size of each frame in milliseconds (e.g., 20, 30, 40, etc.)
+         */
+        fun toCodecHeader(samplingrate: Int, frames_per_packet: Byte, frame_size_ms: Byte) : String{
+            val xx = ByteArray(4)
+            xx[0] = (samplingrate and 0xFF).toByte() // Little Endian
+            xx[1] = ((samplingrate shr 8) and 0xFF).toByte()
+            xx[2] = frames_per_packet
+            xx[3] = frame_size_ms
+            return java.util.Base64.getEncoder().encodeToString(xx)
+        }
+
+        fun fromCodecHeader(header: String) : Triple<Int, Byte, Byte>? {
+            val decoded = java.util.Base64.getDecoder().decode(header)
+            if (decoded.size != 4) return null
+            val samplingrate = (decoded[0].toInt() and 0xFF) or ((decoded[1].toInt() and 0xFF) shl 8)
+            val frames_per_packet = decoded[2]
+            val frame_size_ms = decoded[3]
+            return Triple(samplingrate, frames_per_packet, frame_size_ms)
+        }
     }
 }
\ No newline at end of file
diff --git a/src/zello/Event_OnStreamStart.kt b/src/zello/Event_OnStreamStart.kt
index 6455729..39c9a1f 100644
--- a/src/zello/Event_OnStreamStart.kt
+++ b/src/zello/Event_OnStreamStart.kt
@@ -1,6 +1,8 @@
 package zello
 
 import com.fasterxml.jackson.annotation.JsonPropertyOrder
+import somecodes.Codes.Companion.ValidString
+import somecodes.Codes.Companion.fromCodecHeader
 
 @Suppress("unused")
 @JsonPropertyOrder(value = ["command", "type", "codec", "codec_header", "packet_duration", "stream_id", "channel", "from", "for"])
@@ -14,4 +16,46 @@ class Event_OnStreamStart {
     var channel: String=""
     var from: String = "" // the user who started the stream
     var For: String = ""    // the user who is receiving the stream, should be "for" not "For"
+
+    /**
+     * Get Sampling Rate from codec_header.
+     * @return sampling rate in Hz, or 0 if codec_header is not valid.
+     */
+    fun getSamplingRate() : Int{
+        if (ValidString(codec_header)){
+            val triple = fromCodecHeader(codec_header)
+            if (triple!=null){
+                return triple.first
+            }
+        }
+        return 0
+    }
+
+    /**
+     * Get number of frames per packet, either 1 or 2
+     * @return number of frames per packet, or 0 if codec_header is not valid.
+     */
+    fun getFramesPerSecond() : Byte{
+        if (ValidString(codec_header)){
+            val triple = fromCodecHeader(codec_header)
+            if (triple!=null){
+                return triple.second
+            }
+        }
+        return 0
+    }
+
+    /**
+     * Get audio frame size in miliseconds
+     * @return audio frame size in milliseconds, or 0 if codec_header is not valid.
+     */
+    fun getFrameSizePerMs() : Byte{
+        if (ValidString(codec_header)){
+            val triple = fromCodecHeader(codec_header)
+            if (triple!=null){
+                return triple.third
+            }
+        }
+        return 0
+    }
 }
\ No newline at end of file