[#176] Seekable recording review + m4a remux (merge after PR 158)

.cursor/rules/project-overview.mdc

@@ -11,7 +11,7 @@ Offline-first **Expo SDK 56** (React Native **0.85**, React **19.2.3**) companio
 
 - Entry: `App.tsx` → `initializeDatabase()` → `syncAllData()` → `AppNavigator`
 - App config: `app.config.ts` (EAS project ID, plugins, package id)
-- Screens: `src/app/tabs/` (`ProjectList`, `ViewProject`, `ViewChapter`)
+- Screens: `src/app/tabs/` (`ProjectList`, `ViewProject`, `drafting/DraftingPage` + `RecordTab`)
 - API: `src/services/api.ts` (`FluentAPI`)
 - Sync: `src/services/sync.ts`
 - DB writes: `src/db/repository.ts` | reads: `src/db/queries.ts`

app.config.ts

@@ -74,6 +74,14 @@ const config: ExpoConfig = {
     ],
     './plugins/withRNScreensFragmentFactory',
     'expo-secure-store',
+    'expo-asset',
+    [
+      'expo-audio',
+      {
+        microphonePermission:
+          'Fluent needs access to your microphone so translators can record verse drafts.',
+      },
+    ],
   ],
 };
 

docs/AGENT_ONBOARDING.md

@@ -32,7 +32,7 @@ Quick map for Cursor agents, other coding tools, and new contributors. Verified
 | Path | Purpose |
 |------|---------|
 | [`App.tsx`](../App.tsx) | Root: DB init + initial `syncAllData`, then navigator |
-| [`src/app/tabs/`](../src/app/tabs/) | Screens: `ProjectList`, `ViewProject`, `ViewChapter` |
+| [`src/app/tabs/`](../src/app/tabs/) | Screens: `ProjectList`, `ViewProject`, `drafting/DraftingPage` (parent shell stub for #47) with `RecordTab` (#49) |
 | [`src/navigation/`](../src/navigation/) | Stack navigator |
 | [`src/services/api.ts`](../src/services/api.ts) | HTTP client (`FluentAPI`) — see [api-client-standard.md](guides/api-client-standard.md) |
 | [`src/services/sync.ts`](../src/services/sync.ts) | Sync orchestration, retries, KV counts |
@@ -209,7 +209,9 @@ When adding features: mock `op-sqlite`, navigation, and sync in screen tests fol
 - [x] Dependabot reviewers: `eten-tech-foundation/fluent-admin`
 - [x] Mock or gate `fluent-api.test.ts` for offline CI
 - [ ] Align `format:check` glob with `format` or document intentionally narrow check
-- [ ] Wire `recordings` table to actual audio capture/upload
+- [x] Wire `recordings` table to actual audio capture (issue #49 — upload still pending)
+- [ ] Upload/sync draft recordings to the Fluent server (`sync_status='pending'` rows)
+- [ ] Replace parent drafting shell stub with full #47 implementation (chapter audio player, tab persistence)
 
 ## Related docs
 

modules/aac-remux/android/build.gradle

@@ -0,0 +1,18 @@
+plugins {
+  id 'com.android.library'
+  id 'expo-module-gradle-plugin'
+}
+
+group = 'expo.modules.aacremux'
+version = '0.1.0'
+
+android {
+  namespace "expo.modules.aacremux"
+  defaultConfig {
+    versionCode 1
+    versionName "0.1.0"
+  }
+  lintOptions {
+    abortOnError false
+  }
+}

modules/aac-remux/android/src/main/AndroidManifest.xml

@@ -0,0 +1,2 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+</manifest>

modules/aac-remux/android/src/main/java/expo/modules/aacremux/AacRemuxModule.kt

@@ -0,0 +1,116 @@
+package expo.modules.aacremux
+
+import android.media.MediaCodec
+import android.media.MediaExtractor
+import android.media.MediaFormat
+import android.media.MediaMuxer
+import android.net.Uri
+import expo.modules.kotlin.exception.CodedException
+import expo.modules.kotlin.modules.Module
+import expo.modules.kotlin.modules.ModuleDefinition
+import java.nio.ByteBuffer
+
+/**
+ * Repackages a raw ADTS AAC (`.aac`) recording into an MP4/M4A container without
+ * re-encoding. ADTS is what we capture (self-framing, so it survives a process
+ * kill and concatenates by byte-append), but ExoPlayer cannot reliably seek a
+ * raw ADTS stream. Copying the AAC elementary stream into an MP4 container adds
+ * the sample table that makes review playback seekable — a lossless remux, not
+ * a transcode.
+ */
+class AacRemuxModule : Module() {
+  override fun definition() = ModuleDefinition {
+    Name("AacRemux")
+
+    AsyncFunction("remuxToMp4") { sourceUri: String, destUri: String ->
+      remux(toFilePath(sourceUri), toFilePath(destUri))
+      destUri
+    }
+  }
+
+  private fun toFilePath(uri: String): String =
+    if (uri.startsWith("file://")) {
+      Uri.parse(uri).path ?: uri.removePrefix("file://")
+    } else {
+      uri
+    }
+
+  private fun remux(srcPath: String, dstPath: String) {
+    val extractor = MediaExtractor()
+    var muxer: MediaMuxer? = null
+    var muxerStarted = false
+    try {
+      extractor.setDataSource(srcPath)
+
+      var audioTrackIndex = -1
+      var trackFormat: MediaFormat? = null
+      for (i in 0 until extractor.trackCount) {
+        val candidate = extractor.getTrackFormat(i)
+        val mime = candidate.getString(MediaFormat.KEY_MIME)
+        if (mime != null && mime.startsWith("audio/")) {
+          audioTrackIndex = i
+          trackFormat = candidate
+          break
+        }
+      }
+
+      val format = trackFormat
+        ?: throw CodedException("No audio track found in $srcPath")
+      extractor.selectTrack(audioTrackIndex)
+
+      // ADTS carries no container timestamps, so synthesize monotonically
+      // increasing presentation times from the fixed AAC frame length
+      // (1024 samples per frame). MP4 requires increasing timestamps.
+      val sampleRate = if (format.containsKey(MediaFormat.KEY_SAMPLE_RATE)) {
+        format.getInteger(MediaFormat.KEY_SAMPLE_RATE)
+      } else {
+        44100
+      }
+      val frameDurationUs = 1_000_000L * 1024L / sampleRate
+
+      muxer = MediaMuxer(dstPath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4)
+      val outputTrackIndex = muxer.addTrack(format)
+      muxer.start()
+      muxerStarted = true
+
+      val maxInputSize = if (format.containsKey(MediaFormat.KEY_MAX_INPUT_SIZE)) {
+        format.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE).coerceAtLeast(64 * 1024)
+      } else {
+        256 * 1024
+      }
+      val buffer = ByteBuffer.allocate(maxInputSize)
+      val bufferInfo = MediaCodec.BufferInfo()
+      var presentationTimeUs = 0L
+
+      while (true) {
+        val sampleSize = extractor.readSampleData(buffer, 0)
+        if (sampleSize < 0) {
+          break
+        }
+        bufferInfo.offset = 0
+        bufferInfo.size = sampleSize
+        bufferInfo.presentationTimeUs = presentationTimeUs
+        bufferInfo.flags = MediaCodec.BUFFER_FLAG_KEY_FRAME
+        muxer.writeSampleData(outputTrackIndex, buffer, bufferInfo)
+        presentationTimeUs += frameDurationUs
+        extractor.advance()
+      }
+    } catch (e: CodedException) {
+      throw e
+    } catch (e: Exception) {
+      throw CodedException("Failed to remux AAC to MP4: ${e.message}")
+    } finally {
+      if (muxerStarted) {
+        try {
+          muxer?.stop()
+        } catch (_: Exception) {
+        }
+      }
+      try {
+        muxer?.release()
+      } catch (_: Exception) {
+      }
+      extractor.release()
+    }
+  }
+}

modules/aac-remux/expo-module.config.json

@@ -0,0 +1,6 @@
+{
+  "platforms": ["android"],
+  "android": {
+    "modules": ["expo.modules.aacremux.AacRemuxModule"]
+  }
+}