From b56b4a759c2f7ef70cd87835cebd9e261c874087 Mon Sep 17 00:00:00 2001
From: Siavash Sameni <manwe@MacBook-Air.local>
Date: Mon, 6 Apr 2026 21:17:15 +0400
Subject: [PATCH] revert: use ShortArray audio path (DirectByteBuffer causes
 null ptr crash)

DirectByteBuffer.clear() crashes with null pointer in ART's JIT OSR
compiled code on Android 16. Revert AudioPipeline to use the original
ShortArray writeAudio/readAudio path.

The DirectByteBuffer JNI functions remain in WzpEngine.kt and
jni_bridge.rs for future use once the OSR issue is resolved.

The original SIGBUS from ART GC is rare (~1 crash per 8 min call)
and doesn't warrant the DirectByteBuffer approach until we can
allocate the buffer as a class field outside the hot loop.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 .../main/java/com/wzp/audio/AudioPipeline.kt    | 17 ++---------------
 1 file changed, 2 insertions(+), 15 deletions(-)

diff --git a/android/app/src/main/java/com/wzp/audio/AudioPipeline.kt b/android/app/src/main/java/com/wzp/audio/AudioPipeline.kt
index 363b3c4..9223e50 100644
--- a/android/app/src/main/java/com/wzp/audio/AudioPipeline.kt
+++ b/android/app/src/main/java/com/wzp/audio/AudioPipeline.kt
@@ -205,8 +205,6 @@ class AudioPipeline(private val context: Context) {
         Log.i(TAG, "capture started: ${SAMPLE_RATE}Hz mono, buf=$bufSize, aec=${aec?.enabled}, ns=${ns?.enabled}")
 
         val pcm = ShortArray(FRAME_SAMPLES)
-        // DirectByteBuffer for zero-copy JNI (avoids ART GC SIGBUS on Android 16)
-        val directBuf = ByteBuffer.allocateDirect(FRAME_SAMPLES * 2).order(ByteOrder.LITTLE_ENDIAN)
         // Debug: PCM file + RMS CSV
         var pcmOut: BufferedOutputStream? = null
         var rmsCsv: OutputStreamWriter? = null
@@ -226,10 +224,7 @@ class AudioPipeline(private val context: Context) {
                 val read = recorder.read(pcm, 0, FRAME_SAMPLES)
                 if (read > 0) {
                     applyGain(pcm, read, captureGainDb)
-                    // Zero-copy write via DirectByteBuffer (no GC array interaction)
-                    directBuf.clear()
-                    directBuf.asShortBuffer().put(pcm, 0, read)
-                    engine.writeAudioDirect(directBuf, read)
+                    engine.writeAudio(pcm)
 
                     // Debug: write raw PCM + RMS
                     if (pcmOut != null) {
@@ -292,8 +287,6 @@ class AudioPipeline(private val context: Context) {
 
         val pcm = ShortArray(FRAME_SAMPLES)
         val silence = ShortArray(FRAME_SAMPLES)
-        // DirectByteBuffer for zero-copy JNI (avoids ART GC SIGBUS on Android 16)
-        val directBuf = ByteBuffer.allocateDirect(FRAME_SAMPLES * 2).order(ByteOrder.LITTLE_ENDIAN)
         // Debug: PCM file + RMS CSV for playout
         var pcmOut: BufferedOutputStream? = null
         var rmsCsv: OutputStreamWriter? = null
@@ -310,13 +303,7 @@ class AudioPipeline(private val context: Context) {
         }
         try {
             while (running) {
-                // Zero-copy read via DirectByteBuffer
-                directBuf.clear()
-                val read = engine.readAudioDirect(directBuf, FRAME_SAMPLES)
-                if (read > 0) {
-                    directBuf.rewind()
-                    directBuf.asShortBuffer().get(pcm, 0, read)
-                }
+                val read = engine.readAudio(pcm)
                 if (read >= FRAME_SAMPLES) {
                     applyGain(pcm, read, playoutGainDb)
                     track.write(pcm, 0, read)