feat: improve metadata parsing and visualizer stability

- Enhance metadata extraction in `AudioHelper` by adding `VorbisComment` support and improving "Artist - Title" parsing for Icy streams.
- Implement thread safety in `ExtrasHelper` using a synchronization lock for native visualization and surface lifecycle management.
- Refactor visualizer update logic in `VisualizerFragment` to improve performance and error resilience.
- Remove redundant buffer position calls in `NativeAudioProcessor`.
- Clean up `AudioHelper` logic using Kotlin idiomatic patterns for string building and property access.

app/src/main/java/com/michatec/radio/VisualizerFragment.kt

@@ -99,15 +99,15 @@ class VisualizerFragment : PreferenceFragmentCompat() {
                             if (data != null && data.isNotEmpty()) {
                                 visualizerPref?.update(data)
                             }
-                        } else {
-                            Log.e(TAG, "Custom command failed with result code: ${result.resultCode}")
                         }
-                    } catch (e: Exception) {
+                    } catch (_: Exception) {
-                        Log.e(TAG, "Error fetching visualizer data", e)
+                    } finally {
+                        handler.postDelayed(this, 20)
                     }
                 }, MoreExecutors.directExecutor())
+            } else {
+                handler.postDelayed(this, 100)
             }
-            handler.postDelayed(this, 18) // ~60 FPS
         }
     }
 

app/src/main/java/com/michatec/radio/helpers/AudioHelper.kt

@@ -8,8 +8,9 @@ import androidx.media3.extractor.metadata.icy.IcyHeaders
 import androidx.media3.extractor.metadata.icy.IcyInfo
 import androidx.media3.extractor.metadata.id3.Id3Frame
 import androidx.media3.extractor.metadata.id3.TextInformationFrame
+import androidx.media3.extractor.metadata.vorbis.VorbisComment
 import com.michatec.radio.Keys
-import kotlin.math.min
+import java.util.Locale
 
 
 /*
@@ -28,30 +29,44 @@ object AudioHelper {
         var title = ""
         var artist = ""
         var album = ""
+
         for (i in 0 until metadata.length()) {
-            // extract IceCast metadata
+            // extract metadata
             when (val entry = metadata.get(i)) {
                 is IcyInfo -> {
-                    title = entry.title.toString()
+                    val streamTitle = entry.title
+                    if (!streamTitle.isNullOrEmpty()) {
+                        if (streamTitle.contains(" - ")) {
+                            artist = streamTitle.substringBefore(" - ").trim()
+                            title = streamTitle.substringAfter(" - ").trim()
+                        } else {
+                            title = streamTitle
+                        }
+                    }
                 }
 
                 is IcyHeaders -> {
-                    Log.i(TAG, "icyHeaders:" + entry.name + " - " + entry.genre)
+                    Log.i(TAG, "icyHeaders: ${entry.name} - ${entry.genre}")
                 }
 
                 is Id3Frame -> {
-                    when (entry) {
+                    if (entry is TextInformationFrame) {
-                        is TextInformationFrame -> {
                         when (entry.id) {
-                                "TIT2" -> title = entry.values.getOrNull(0) ?: "" // Title
+                            "TIT2" -> entry.values.getOrNull(0)?.let { if (it.isNotEmpty()) title = it.trim() } // Title
-                                "TPE1" -> artist = entry.values.getOrNull(0) ?: "" // Artist
+                            "TPE1" -> entry.values.getOrNull(0)?.let { if (it.isNotEmpty()) artist = it.trim() } // Artist
-                                "TALB" -> album = entry.values.getOrNull(0) ?: "" // Album
+                            "TALB" -> entry.values.getOrNull(0)?.let { if (it.isNotEmpty()) album = it.trim() } // Album
                         }
-                        }
+                    } else {
-                        else -> {
                         Log.d(TAG, "Unhandled ID3 frame: ${entry.javaClass.simpleName}")
                     }
                 }
+
+                is VorbisComment -> {
+                    when (entry.key.uppercase(Locale.ROOT)) {
+                        "TITLE" -> if (entry.value.isNotEmpty()) title = entry.value.trim()
+                        "ARTIST" -> if (entry.value.isNotEmpty()) artist = entry.value.trim()
+                        "ALBUM" -> if (entry.value.isNotEmpty()) album = entry.value.trim()
+                    }
                 }
 
                 else -> {
@@ -59,19 +74,21 @@ object AudioHelper {
                 }
             }
         }
+
         // Build metadata string
-        var metadataString = title
+        var metadataString = when {
-        if (artist.isNotEmpty() && title.isNotEmpty()) {
+            artist.isNotEmpty() && title.isNotEmpty() -> "$artist - $title"
-            metadataString = "$artist - $title"
+            artist.isNotEmpty() -> artist
+            title.isNotEmpty() -> title
+            else -> ""
         }
+
         if (album.isNotEmpty() && metadataString.isNotEmpty()) {
             metadataString += " ($album)"
         }
+
         // ensure a max length of the metadata string
-        if (metadataString.isNotEmpty()) {
+        return metadataString.take(Keys.DEFAULT_MAX_LENGTH_OF_METADATA_ENTRY)
-            metadataString = metadataString.take(min(metadataString.length, Keys.DEFAULT_MAX_LENGTH_OF_METADATA_ENTRY))
-        }
-        return metadataString
     }
 
 

app/src/main/java/com/michatec/radio/helpers/ExtrasHelper.kt

@@ -27,7 +27,11 @@ class ExtrasHelper {
         @JvmStatic
         private external fun visualize(surface: Surface, data: FloatArray)
 
-        fun render(surface: Surface, data: FloatArray) {
+        private val renderLock = Any()
+
+        fun render(surface: Surface?, data: FloatArray) {
+            if (surface == null) return
+            synchronized(renderLock) {
                 if (!surface.isValid) return
                 try {
                     visualize(surface, data)
@@ -36,6 +40,7 @@ class ExtrasHelper {
                 }
             }
         }
+    }
 
     class VisualizerPreference(context: Context, attrs: AttributeSet? = null) : Preference(context, attrs) {
         private var visualizerView: VisualizerView? = null
@@ -97,22 +102,25 @@ class ExtrasHelper {
         }
 
         fun update(data: FloatArray) {
-            val s = surface
+            render(surface, data)
-            if (s != null && s.isValid) {
-                render(s, data)
-            }
         }
 
         override fun surfaceCreated(holder: SurfaceHolder) {
+            synchronized(renderLock) {
                 surface = holder.surface
             }
+        }
 
         override fun surfaceChanged(holder: SurfaceHolder, format: Int, width: Int, height: Int) {
+            synchronized(renderLock) {
                 surface = holder.surface
             }
+        }
 
         override fun surfaceDestroyed(holder: SurfaceHolder) {
+            synchronized(renderLock) {
                 surface = null
             }
         }
+    }
 }

app/src/main/java/com/michatec/radio/helpers/NativeAudioProcessor.kt

@@ -74,7 +74,6 @@ class NativeAudioProcessor : BaseAudioProcessor() {
                 directBuffer = ByteBuffer.allocateDirect(size).order(ByteOrder.nativeOrder())
             }
             directBuffer!!.clear()
-            inputBuffer.position()
             directBuffer!!.put(inputBuffer)
             directBuffer!!.flip()
             bufferToProcess = directBuffer!!
@@ -84,7 +83,6 @@ class NativeAudioProcessor : BaseAudioProcessor() {
 
         val out = replaceOutputBuffer(size)
         out.order(ByteOrder.nativeOrder())
-        bufferToProcess.position(0)
         out.put(bufferToProcess)
         out.flip()
     }