fix: Add pasp box to declare square pixels (1:1) for web playback

The codec string fix caused videos to appear squished on web players
like Shaka. Adding an explicit pixel aspect ratio (pasp) box with
1:1 ratio tells the player not to apply any SAR scaling.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package/android/src/main/java/com/mrousavy/camera/core/CameraSession.kt

@@ -428,19 +428,21 @@ class CameraSession(private val context: Context, private val cameraManager: Cam
 
       // Get actual device rotation from WindowManager since the React Native orientation hook
       // doesn't update when rotating between landscape-left and landscape-right on Android.
-      // Map device rotation to the correct orientationHint for video recording:
-      // - Counter-clockwise (ROTATION_90) → 270° hint
-      // - Clockwise (ROTATION_270) → 90° hint
+      // Map device rotation to the correct orientation for video recording.
+      // Surface.ROTATION_90 = device rotated 90° CCW = phone top on LEFT = LANDSCAPE_LEFT
+      // Surface.ROTATION_270 = device rotated 90° CW = phone top on RIGHT = LANDSCAPE_RIGHT
       val windowManager = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
       val deviceRotation = windowManager.defaultDisplay.rotation
       val recordingOrientation = when (deviceRotation) {
         Surface.ROTATION_0 -> Orientation.PORTRAIT
-        Surface.ROTATION_90 -> Orientation.LANDSCAPE_RIGHT
+        Surface.ROTATION_90 -> Orientation.LANDSCAPE_LEFT
         Surface.ROTATION_180 -> Orientation.PORTRAIT_UPSIDE_DOWN
-        Surface.ROTATION_270 -> Orientation.LANDSCAPE_LEFT
+        Surface.ROTATION_270 -> Orientation.LANDSCAPE_RIGHT
         else -> Orientation.PORTRAIT
       }
 
+      Log.i(TAG, "startRecording: orientation=${recordingOrientation.toDegrees()}° (deviceRotation=$deviceRotation)")
+
       val recording = RecordingSession(
         context,
         cameraId,
@@ -448,7 +450,7 @@ class CameraSession(private val context: Context, private val cameraManager: Cam
         enableAudio,
         fps,
         videoOutput.enableHdr,
-        orientation,
+        recordingOrientation,
         options,
         filePath,
         callback,

package/android/src/main/java/com/mrousavy/camera/core/ChunkedRecorder.kt

@@ -30,8 +30,15 @@ class ChunkedRecordingManager(private val encoder: MediaCodec, private val outpu
       iFrameInterval: Int = 5
     ): ChunkedRecordingManager {
       val mimeType = options.videoCodec.toMimeType()
-      val cameraOrientationDegrees = cameraOrientation.toDegrees()
-      val recordingOrientationDegrees = (options.orientation ?: Orientation.PORTRAIT).toDegrees();
+      // Use cameraOrientation (from WindowManager) for rotation metadata
+      // The options.orientation from JavaScript is unreliable on Android when rotating between landscape modes
+      // Note: MediaMuxer.setOrientationHint() uses opposite convention from HlsMuxer's rotation matrix
+      // We need to invert the rotation: 90 <-> 270, while 0 and 180 stay the same
+      val orientationDegrees = when (cameraOrientation.toDegrees()) {
+        90 -> 270
+        270 -> 90
+        else -> cameraOrientation.toDegrees()
+      }
       val (width, height) = if (cameraOrientation.isLandscape()) {
         size.height to size.width
       } else {
@@ -55,12 +62,12 @@ class ChunkedRecordingManager(private val encoder: MediaCodec, private val outpu
       format.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, iFrameInterval)
       format.setInteger(MediaFormat.KEY_BIT_RATE, bitRate)
 
-      Log.d(TAG, "Video Format: $format, camera orientation $cameraOrientationDegrees, recordingOrientation: $recordingOrientationDegrees")
+      Log.d(TAG, "Video Format: $format, orientation: $orientationDegrees")
       // Create a MediaCodec encoder, and configure it with our format.  Get a Surface
       // we can use for input and wrap it with a class that handles the EGL work.
       codec.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE)
       return ChunkedRecordingManager(
-        codec, outputDirectory, recordingOrientationDegrees, iFrameInterval, callbacks
+        codec, outputDirectory, orientationDegrees, iFrameInterval, callbacks
       )
     }
   }
@@ -91,12 +98,13 @@ class ChunkedRecordingManager(private val encoder: MediaCodec, private val outpu
       muxer.start()
     }
 
+    fun writeSample(buffer: java.nio.ByteBuffer, bufferInfo: BufferInfo) {
+      muxer.writeSampleData(videoTrack, buffer, bufferInfo)
+    }
 
     fun finish() {
       muxer.stop()
       muxer.release()
-      // Calculate duration from start time - this is approximate
-      // The new FragmentedRecordingManager provides accurate duration
       callbacks.onVideoChunkReady(filepath, chunkIndex, null)
     }
   }
@@ -170,7 +178,7 @@ class ChunkedRecordingManager(private val encoder: MediaCodec, private val outpu
         encoder.releaseOutputBuffer(index, false)
         return
       }
-      context.muxer.writeSampleData(context.videoTrack, encodedData, bufferInfo)
+      context.writeSample(encodedData, bufferInfo)
       encoder.releaseOutputBuffer(index, false)
     }
   }

package/android/src/main/java/com/mrousavy/camera/core/FragmentedRecordingManager.kt

@@ -39,8 +39,9 @@ class FragmentedRecordingManager(
             segmentDurationSeconds: Int = DEFAULT_SEGMENT_DURATION_SECONDS
         ): FragmentedRecordingManager {
             val mimeType = options.videoCodec.toMimeType()
-            val cameraOrientationDegrees = cameraOrientation.toDegrees()
-            val recordingOrientationDegrees = (options.orientation ?: Orientation.PORTRAIT).toDegrees()
+            // Use cameraOrientation (from WindowManager) for rotation metadata
+            // The options.orientation from JavaScript is unreliable on Android when rotating between landscape modes
+            val orientationDegrees = cameraOrientation.toDegrees()
 
             // Swap dimensions based on camera orientation, same as ChunkedRecordingManager
             val (width, height) = if (cameraOrientation.isLandscape()) {
@@ -49,9 +50,7 @@ class FragmentedRecordingManager(
                 size.width to size.height
             }
 
-            Log.d(TAG, "Input size: ${size.width}x${size.height}, encoder size: ${width}x${height}, " +
-                    "cameraOrientation: $cameraOrientation ($cameraOrientationDegrees°), " +
-                    "recordingOrientation: $recordingOrientationDegrees°")
+            Log.d(TAG, "Recording: ${width}x${height}, orientation=$orientationDegrees°")
 
             val format = MediaFormat.createVideoFormat(mimeType, width, height)
             val codec = MediaCodec.createEncoderByType(mimeType)
@@ -61,16 +60,18 @@ class FragmentedRecordingManager(
                 MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface
             )
 
-            val effectiveFps = fps ?: 30
+            // Use 30fps as conservative default since many Android devices can't sustain
+            // higher frame rates at high resolutions. This affects:
+            // - Encoder: bitrate allocation and I-frame interval calculation
+            // - HlsMuxer: timescale for accurate sample durations
+            // The actual frame timing comes from camera timestamps regardless of this setting.
+            val effectiveFps = 30
             format.setInteger(MediaFormat.KEY_FRAME_RATE, effectiveFps)
             format.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, segmentDurationSeconds)
             format.setInteger(MediaFormat.KEY_BIT_RATE, bitRate)
 
-            Log.d(TAG, "Video Format: $format, orientation: $recordingOrientationDegrees")
-
             codec.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE)
 
-            // Create muxer with callbacks and orientation
             val muxer = HlsMuxer(
                 outputDirectory = outputDirectory,
                 callback = object : HlsMuxer.Callback {
@@ -82,12 +83,11 @@ class FragmentedRecordingManager(
                         callbacks.onVideoChunkReady(file, index, durationUs)
                     }
                 },
-                orientationDegrees = recordingOrientationDegrees
+                orientationDegrees = orientationDegrees,
+                fps = effectiveFps
             )
             muxer.setSegmentDuration(segmentDurationSeconds * 1_000_000L)
 
-            Log.d(TAG, "Created HlsMuxer with orientation: $recordingOrientationDegrees degrees")
-
             return FragmentedRecordingManager(codec, muxer)
         }
     }

package/android/src/main/java/com/mrousavy/camera/core/HlsMuxer.kt

@@ -27,7 +27,8 @@ import java.nio.ByteBuffer
 class HlsMuxer(
     private val outputDirectory: File,
     private val callback: Callback,
-    private val orientationDegrees: Int = 0
+    private val orientationDegrees: Int = 0,
+    private val fps: Int = 30
 ) {
     companion object {
         private const val TAG = "HlsMuxer"
@@ -41,7 +42,7 @@ class HlsMuxer(
 
     // Configuration
     private var targetSegmentDurationUs: Long = DEFAULT_SEGMENT_DURATION_US
-    private var timescale: Int = 30000  // Default, updated from format
+    private var timescale: Int = 30000  // Default, updated in addTrack() to fps * 1000
 
     // State
     private var state = State.UNINITIALIZED
@@ -54,6 +55,14 @@ class HlsMuxer(
     private var segmentStartTimeUs = -1L
     private var lastPresentationTimeUs = 0L
 
+    // Timestamp normalization - MediaCodec timestamps are device uptime, not starting from 0
+    private var firstPresentationTimeUs = -1L
+
+    // Actual fps detection from frame timestamps
+    private var detectedFps: Int? = null
+    private var fpsDetectionSamples = mutableListOf<Long>()
+    private val FPS_DETECTION_SAMPLE_COUNT = 30
+
     private enum class State {
         UNINITIALIZED,
         INITIALIZED,
@@ -69,6 +78,29 @@ class HlsMuxer(
         val isKeyFrame: Boolean
     )
 
+    // ==================== Timestamp Normalization ====================
+
+    /**
+     * Normalizes a presentation timestamp to start from 0.
+     * The first timestamp received becomes time 0, and all subsequent
+     * timestamps are relative to that.
+     *
+     * This is necessary because MediaCodec timestamps are based on device uptime,
+     * not starting from 0. HLS players expect timestamps to start at or near 0.
+     */
+    private fun normalizeTimestamp(rawPresentationTimeUs: Long): Long {
+        if (firstPresentationTimeUs < 0) {
+            firstPresentationTimeUs = rawPresentationTimeUs
+            Log.d(TAG, "First timestamp captured: ${rawPresentationTimeUs}us (${rawPresentationTimeUs / 1_000_000.0}s), normalizing to 0")
+        }
+        val normalized = rawPresentationTimeUs - firstPresentationTimeUs
+        // Log first few normalizations to debug
+        if (normalized < 1_000_000) { // First second
+            Log.d(TAG, "Timestamp: raw=${rawPresentationTimeUs}us -> normalized=${normalized}us")
+        }
+        return normalized
+    }
+
     // ==================== Annex-B to AVCC Conversion ====================
 
     /**
@@ -201,13 +233,11 @@ class HlsMuxer(
 
         trackFormat = format
 
-        // Extract timescale from frame rate
-        val fps = try {
-            format.getInteger(MediaFormat.KEY_FRAME_RATE)
-        } catch (e: Exception) {
-            30
-        }
-        timescale = fps * 1000  // Use fps * 1000 for good precision
+        // Use fps * 1000 as timescale for good precision (1000 timescale units per frame).
+        // This ensures accurate sample durations without integer truncation issues.
+        // Note: ffprobe may report r_frame_rate based on timescale, so the backend
+        // should use the explicit framesPerSecond from the API mutation, not ffprobe.
+        timescale = fps * 1000
 
         state = State.INITIALIZED
 
@@ -215,7 +245,7 @@ class HlsMuxer(
         val formatHeight = try { format.getInteger(MediaFormat.KEY_HEIGHT) } catch (e: Exception) { -1 }
         Log.d(TAG, "Added track: ${format.getString(MediaFormat.KEY_MIME)}, " +
                 "encoder output: ${formatWidth}x${formatHeight}, " +
-                "timescale=$timescale, orientation=$orientationDegrees°")
+                "fps=$fps, timescale=$timescale, orientation=$orientationDegrees°")
 
         return 0  // Single track, index 0
     }
@@ -227,16 +257,30 @@ class HlsMuxer(
         check(state == State.INITIALIZED) { "Must call addTrack() before start()" }
         val format = trackFormat ?: throw IllegalStateException("No track format")
 
-        // Create output directory if needed
+        // Create output directory if needed, with proper error handling
         if (!outputDirectory.exists()) {
-            outputDirectory.mkdirs()
+            val created = outputDirectory.mkdirs()
+            if (!created && !outputDirectory.exists()) {
+                throw IllegalStateException(
+                    "Failed to create output directory: ${outputDirectory.absolutePath}. " +
+                    "Parent exists: ${outputDirectory.parentFile?.exists()}, " +
+                    "Parent path: ${outputDirectory.parentFile?.absolutePath}"
+                )
+            }
+            Log.d(TAG, "Created output directory: ${outputDirectory.absolutePath}")
         }
 
         // Write init segment
         val initBytes = buildInitSegment(format)
         val initFile = File(outputDirectory, "init.mp4")
         FileOutputStream(initFile).use { it.write(initBytes) }
+
+        // Log frame rate metadata for debugging
+        val defaultSampleDuration = timescale / fps
         Log.d(TAG, "Created init segment: ${initFile.absolutePath} (${initBytes.size} bytes)")
+        Log.d(TAG, "Frame rate metadata: timescale=$timescale, fps=$fps, " +
+                "default_sample_duration=$defaultSampleDuration (ffprobe should calculate ${timescale}/${defaultSampleDuration}=${fps}fps)")
+
         callback.onInitSegmentReady(initFile)
 
         state = State.STARTED
@@ -259,13 +303,40 @@ class HlsMuxer(
         }
 
         val isKeyFrame = (bufferInfo.flags and MediaCodec.BUFFER_FLAG_KEY_FRAME) != 0
-        val presentationTimeUs = bufferInfo.presentationTimeUs
+        // Normalize timestamp to start from 0 (MediaCodec uses device uptime)
+        val presentationTimeUs = normalizeTimestamp(bufferInfo.presentationTimeUs)
+
+        // Detect actual fps from first N samples
+        if (detectedFps == null) {
+            fpsDetectionSamples.add(presentationTimeUs)
+            if (fpsDetectionSamples.size >= FPS_DETECTION_SAMPLE_COUNT) {
+                val elapsed = fpsDetectionSamples.last() - fpsDetectionSamples.first()
+                if (elapsed > 0) {
+                    val actualFps = ((FPS_DETECTION_SAMPLE_COUNT - 1) * 1_000_000.0 / elapsed).toInt()
+                    detectedFps = actualFps
+                    if (kotlin.math.abs(actualFps - fps) > 5) {
+                        Log.w(TAG, "Actual fps ($actualFps) differs significantly from configured fps ($fps)! " +
+                                "This may cause processing issues if backend uses configured fps.")
+                    } else {
+                        Log.d(TAG, "Detected actual fps: $actualFps (configured: $fps)")
+                    }
+                }
+                fpsDetectionSamples.clear() // Free memory
+            }
+        }
 
         // Initialize segment start time
         if (segmentStartTimeUs < 0) {
             segmentStartTimeUs = presentationTimeUs
         }
 
+        // Update duration of previous sample BEFORE finalization check
+        // This ensures the last sample has correct duration when segment is finalized
+        if (pendingSamples.isNotEmpty()) {
+            val lastSample = pendingSamples.last()
+            lastSample.durationUs = presentationTimeUs - lastSample.presentationTimeUs
+        }
+
         // Check if we should finalize current segment (at keyframe boundaries)
         if (isKeyFrame && pendingSamples.isNotEmpty()) {
             val segmentDurationUs = presentationTimeUs - segmentStartTimeUs
@@ -284,12 +355,6 @@ class HlsMuxer(
         // Convert Annex-B (start codes) to AVCC (length prefixes)
         val data = convertAnnexBToAvcc(rawData)
 
-        // Update duration of previous sample
-        if (pendingSamples.isNotEmpty()) {
-            val lastSample = pendingSamples.last()
-            lastSample.durationUs = presentationTimeUs - lastSample.presentationTimeUs
-        }
-
         // Estimate duration (will be corrected by next sample)
         val estimatedDurationUs = if (lastPresentationTimeUs > 0) {
             presentationTimeUs - lastPresentationTimeUs
@@ -351,6 +416,7 @@ class HlsMuxer(
             val durationUs = (lastSample.presentationTimeUs - firstPts) + lastSample.durationUs
 
             Log.d(TAG, "Created segment $segmentIndex: samples=${pendingSamples.size}, " +
+                    "baseDecodeTime=${baseDecodeTimeUs}us (${baseDecodeTimeUs / 1_000_000.0}s), " +
                     "duration=${durationUs / 1000}ms, size=${fragmentBytes.size} bytes")
 
             callback.onMediaSegmentReady(segmentFile, segmentIndex, durationUs)
@@ -649,7 +715,7 @@ class HlsMuxer(
     private fun buildStblBox(width: Int, height: Int, sps: ByteArray, pps: ByteArray): ByteArray {
         val content = ByteArrayOutputStream()
         content.write(buildStsdBox(width, height, sps, pps))
-        content.write(buildEmptySttsBox())
+        content.write(buildSttsBox())  // Contains default timing for ffprobe frame rate detection
         content.write(buildEmptyStscBox())
         content.write(buildEmptyStszBox())
         content.write(buildEmptyStcoBox())
@@ -687,17 +753,32 @@ class HlsMuxer(
         dos.writeShort(-1)              // pre-defined
 
         output.write(buildAvcCBox(sps, pps))
+        output.write(buildPaspBox())
 
         return wrapBox("avc1", output.toByteArray())
     }
 
+    /**
+     * Builds pixel aspect ratio box to explicitly declare square pixels (1:1).
+     * This helps players correctly interpret video dimensions without SAR scaling.
+     */
+    private fun buildPaspBox(): ByteArray {
+        val output = ByteArrayOutputStream()
+        val dos = DataOutputStream(output)
+        dos.writeInt(1)  // hSpacing (horizontal)
+        dos.writeInt(1)  // vSpacing (vertical)
+        return wrapBox("pasp", output.toByteArray())
+    }
+
     private fun buildAvcCBox(sps: ByteArray, pps: ByteArray): ByteArray {
         val output = ByteArrayOutputStream()
         val dos = DataOutputStream(output)
 
-        val profileIdc = if (sps.isNotEmpty()) sps[0].toInt() and 0xFF else 0x42
-        val profileCompat = if (sps.size > 1) sps[1].toInt() and 0xFF else 0x00
-        val levelIdc = if (sps.size > 2) sps[2].toInt() and 0xFF else 0x1F
+        // SPS NAL unit format: [NAL header, profile_idc, constraint_flags, level_idc, ...]
+        // Skip byte 0 (NAL header, typically 0x67) to get the actual profile data
+        val profileIdc = if (sps.size > 1) sps[1].toInt() and 0xFF else 0x42
+        val profileCompat = if (sps.size > 2) sps[2].toInt() and 0xFF else 0x00
+        val levelIdc = if (sps.size > 3) sps[3].toInt() and 0xFF else 0x1F
 
         dos.writeByte(1)            // configuration version
         dos.writeByte(profileIdc)   // AVC profile
@@ -716,11 +797,21 @@ class HlsMuxer(
         return wrapBox("avcC", output.toByteArray())
     }
 
-    private fun buildEmptySttsBox(): ByteArray {
+    private fun buildSttsBox(): ByteArray {
         val output = ByteArrayOutputStream()
         val dos = DataOutputStream(output)
+
+        // For fragmented MP4, stts is normally empty as timing is in trun boxes.
+        // However, ffprobe uses stts to calculate r_frame_rate when present.
+        // We add a single entry with the default sample duration so ffprobe
+        // can derive: r_frame_rate = timescale / sample_delta = 30000/1000 = 30
+        val defaultSampleDuration = timescale / fps
+
         dos.writeInt(0)  // version & flags
-        dos.writeInt(0)  // entry count
+        dos.writeInt(1)  // entry count (1 entry for default timing)
+        dos.writeInt(1)  // sample_count (indicates this is the default duration)
+        dos.writeInt(defaultSampleDuration)  // sample_delta in timescale units
+
         return wrapBox("stts", output.toByteArray())
     }
 
@@ -757,10 +848,15 @@ class HlsMuxer(
         val output = ByteArrayOutputStream()
         val dos = DataOutputStream(output)
 
+        // Calculate default sample duration so ffprobe can derive correct fps
+        // fps = timescale / default_sample_duration
+        // At 30fps with timescale=30000: duration=1000, ffprobe calculates 30000/1000=30
+        val defaultSampleDuration = timescale / fps
+
         dos.writeInt(0)  // version & flags
         dos.writeInt(1)  // track ID
         dos.writeInt(1)  // default sample description index
-        dos.writeInt(0)  // default sample duration
+        dos.writeInt(defaultSampleDuration)  // default sample duration
         dos.writeInt(0)  // default sample size
         dos.writeInt(0)  // default sample flags
 
@@ -804,9 +900,11 @@ class HlsMuxer(
     ): ByteArray {
         // Calculate sizes to determine data offset
         val mfhdBox = buildMfhdBox(sequenceNumber)
-        val tfhdSize = 8 + 8   // box header + content (version/flags + track_id)
+        // tfhd: 8 header + 4 version/flags + 4 track_id + 4 duration + 4 size + 4 flags = 28 bytes
+        val tfhdSize = 8 + 20
         val tfdtSize = 8 + 12  // box header + version 1 content
-        val trunSize = 8 + 12 + (samples.size * 12)  // header + fixed + per-sample (no composition offset)
+        // trun: 8 header + 12 fixed + per-sample (size + flags only, no duration)
+        val trunSize = 8 + 12 + (samples.size * 8)
         val trafSize = 8 + tfhdSize + tfdtSize + trunSize
         val moofSize = 8 + mfhdBox.size + trafSize
 
@@ -841,9 +939,21 @@ class HlsMuxer(
         val output = ByteArrayOutputStream()
         val dos = DataOutputStream(output)
 
-        // Flags: default-base-is-moof (0x020000)
-        dos.writeInt(0x00020000)
+        // Calculate default sample duration for this fragment
+        // This helps ffprobe calculate correct frame rate when reading via HLS
+        val defaultSampleDuration = timescale / fps  // e.g., 30000/30 = 1000
+
+        // Match iOS AVFoundation's tfhd structure (28 bytes total)
+        // Flags: default-base-is-moof (0x020000) + default-sample-duration (0x000008)
+        //        + default-sample-size (0x000010) + default-sample-flags (0x000020)
+        val flags = 0x00020000 or 0x000008 or 0x000010 or 0x000020
+        dos.writeInt(flags)
         dos.writeInt(1)  // track ID
+        dos.writeInt(defaultSampleDuration)  // default sample duration in timescale units
+        dos.writeInt(0)  // default sample size (0 = variable, specified in trun)
+        dos.writeInt(0x01010000)  // default sample flags (non-keyframe, depends on others)
+
+        Log.d(TAG, "tfhd: default_sample_duration=$defaultSampleDuration (timescale=$timescale, fps=$fps)")
 
         return wrapBox("tfhd", output.toByteArray())
     }
@@ -866,16 +976,17 @@ class HlsMuxer(
         val output = ByteArrayOutputStream()
         val dos = DataOutputStream(output)
 
-        // Flags: data-offset + sample-duration + sample-size + sample-flags
-        val flags = 0x000001 or 0x000100 or 0x000200 or 0x000400
+        // Flags: data-offset + sample-size + sample-flags
+        // NOTE: We intentionally OMIT sample-duration (0x000100) so ffprobe uses
+        // the default_sample_duration from tfhd instead of per-sample durations.
+        // This ensures consistent frame rate calculation via HLS.
+        val flags = 0x000001 or 0x000200 or 0x000400
         dos.writeInt(flags)
         dos.writeInt(samples.size)
         dos.writeInt(dataOffset)
 
         for (sample in samples) {
-            // Convert duration to timescale units
-            val durationInTimescale = ((sample.durationUs * timescale) / 1_000_000).toInt()
-            dos.writeInt(durationInTimescale)
+            // No duration - using default from tfhd
             dos.writeInt(sample.data.size)
             dos.writeInt(buildSampleFlags(sample.isKeyFrame))
         }

package/android/src/main/java/com/mrousavy/camera/core/RecordingSession.kt

@@ -8,6 +8,7 @@ import com.facebook.common.statfs.StatFsHelper
 import com.mrousavy.camera.extensions.getRecommendedBitRate
 import com.mrousavy.camera.types.Orientation
 import com.mrousavy.camera.types.RecordVideoOptions
+import com.mrousavy.camera.types.StreamSegmentType
 import com.mrousavy.camera.utils.FileUtils
 import java.io.File
 import android.os.Environment
@@ -27,9 +28,7 @@ class RecordingSession(
   private val filePath: String,
   private val callback: (video: Video) -> Unit,
   private val onError: (error: CameraError) -> Unit,
-  private val allCallbacks: CameraSession.Callback,
-  // Use FragmentedRecordingManager for HLS-compatible fMP4 output
-  private val useFragmentedMp4: Boolean = true
+  private val allCallbacks: CameraSession.Callback
 ) {
   companion object {
     private const val TAG = "RecordingSession"
@@ -44,13 +43,15 @@ class RecordingSession(
 
   data class Video(val path: String, val durationMs: Long, val size: Size)
 
-  private val outputPath: File = File(filePath)
+  // Normalize path - expo-file-system passes file:// URIs but File expects raw paths
+  // Handle both file:// and file:/ variants
+  private val outputPath: File = File(filePath.replace(Regex("^file:/+"), "/"))
 
   private val bitRate = getBitRate()
 
   // Use FragmentedRecordingManager for HLS-compatible fMP4 output,
   // or fall back to ChunkedRecordingManager for regular MP4 chunks
-  private val recorder: ChunkedRecorderInterface = if (useFragmentedMp4) {
+  private val recorder: ChunkedRecorderInterface = if (options.streamSegmentType == StreamSegmentType.FRAGMENTED_MP4) {
     FragmentedRecordingManager.fromParams(
       allCallbacks,
       size,
@@ -82,7 +83,7 @@ class RecordingSession(
 
   fun start() {
     synchronized(this) {
-      Log.i(TAG, "Starting RecordingSession..")
+      Log.i(TAG, "Starting RecordingSession with ${options.streamSegmentType} recorder..")
       startTime = System.currentTimeMillis()
       recorder.start()
     }

package/android/src/main/java/com/mrousavy/camera/types/RecordVideoOptions.kt

@@ -9,6 +9,7 @@ class RecordVideoOptions(map: ReadableMap) {
   var videoBitRateOverride: Double? = null
   var videoBitRateMultiplier: Double? = null
   var orientation: Orientation? = null
+  var streamSegmentType: StreamSegmentType = StreamSegmentType.FRAGMENTED_MP4
 
   init {
     if (map.hasKey("fileType")) {
@@ -29,5 +30,8 @@ class RecordVideoOptions(map: ReadableMap) {
     if (map.hasKey("orientation")) {
       orientation = Orientation.fromUnionValue(map.getString("orientation"))
     }
+    if (map.hasKey("streamSegmentType")) {
+      streamSegmentType = StreamSegmentType.fromUnionValue(map.getString("streamSegmentType"))
+    }
   }
 }

package/android/src/main/java/com/mrousavy/camera/types/StreamSegmentType.kt

@@ -0,0 +1,15 @@
+package com.mrousavy.camera.types
+
+enum class StreamSegmentType(override val unionValue: String) : JSUnionValue {
+  FRAGMENTED_MP4("FRAGMENTED_MP4"),
+  RB_CHUNKED_MP4("RB_CHUNKED_MP4");
+
+  companion object : JSUnionValue.Companion<StreamSegmentType> {
+    override fun fromUnionValue(unionValue: String?): StreamSegmentType =
+      when (unionValue) {
+        "FRAGMENTED_MP4" -> FRAGMENTED_MP4
+        "RB_CHUNKED_MP4" -> RB_CHUNKED_MP4
+        else -> FRAGMENTED_MP4 // Default to fMP4
+      }
+  }
+}

package/ios/Core/CameraSession+Video.swift

@@ -20,6 +20,9 @@ extension CameraSession {
                       onError: @escaping (_ error: CameraError) -> Void) {
     // Run on Camera Queue
     CameraQueues.cameraQueue.async {
+      // Normalize path - expo-file-system passes file:// URIs but FileManager expects raw paths
+      let normalizedPath = filePath.hasPrefix("file://") ? String(filePath.dropFirst(7)) : filePath
+
       let start = DispatchTime.now()
       ReactLogger.log(level: .info, message: "Starting Video recording...")
 
@@ -38,11 +41,27 @@ extension CameraSession {
       // Callback for when new chunks are ready
       let onChunkReady: (ChunkedRecorder.Chunk) -> Void = { chunk in
         guard let delegate = self.delegate else {
+          ReactLogger.log(level: .warning, message: "Chunk ready but delegate is nil, dropping chunk: \(chunk)")
           return
         }
         delegate.onVideoChunkReady(chunk: chunk)
       }
 
+      // Callback for when a chunk write fails (e.g. init file write failure)
+      let onChunkError: (Error) -> Void = { error in
+        ReactLogger.log(level: .error, message: "Chunk write error, stopping recording: \(error.localizedDescription)")
+        // Stop recording immediately
+        if let session = self.recordingSession {
+          session.stop(clock: self.captureSession.clock)
+        }
+        // Surface error to RN
+        if let cameraError = error as? CameraError {
+          onError(cameraError)
+        } else {
+          onError(.capture(.fileError))
+        }
+      }
+
       // Callback for when the recording ends
       let onFinish = { (recordingSession: RecordingSession, status: AVAssetWriter.Status, error: Error?) in
         defer {
@@ -82,22 +101,23 @@ extension CameraSession {
         }
       }
 
-      if !FileManager.default.fileExists(atPath: filePath) {
+      if !FileManager.default.fileExists(atPath: normalizedPath) {
         do {
-          try FileManager.default.createDirectory(atPath: filePath, withIntermediateDirectories: true)
+          try FileManager.default.createDirectory(atPath: normalizedPath, withIntermediateDirectories: true)
         } catch {
           onError(.capture(.createRecordingDirectoryError(message: error.localizedDescription)))
           return
         }
       }
 
-      ReactLogger.log(level: .info, message: "Will record to temporary file: \(filePath)")
+      ReactLogger.log(level: .info, message: "Will record to temporary file: \(normalizedPath)")
 
       do {
         // Create RecordingSession for the temp file
-        let recordingSession = try RecordingSession(outputDiretory: filePath,
+        let recordingSession = try RecordingSession(outputDiretory: normalizedPath,
                                                     fileType: options.fileType,
                                                     onChunkReady: onChunkReady,
+                                                    onChunkError: onChunkError,
                                                     completion: onFinish)
 
         // Init Audio + Activate Audio Session (optional)

package/ios/Core/ChunkedRecorder.swift

@@ -24,12 +24,14 @@ class ChunkedRecorder: NSObject {
 
   let outputURL: URL
   let onChunkReady: ((Chunk) -> Void)
+  let onError: ((Error) -> Void)?
 
   private var chunkIndex: UInt64 = 0
 
-  init(outputURL: URL, onChunkReady: @escaping ((Chunk) -> Void)) throws {
+  init(outputURL: URL, onChunkReady: @escaping ((Chunk) -> Void), onError: ((Error) -> Void)? = nil) throws {
     self.outputURL = outputURL
     self.onChunkReady = onChunkReady
+    self.onError = onError
     guard FileManager.default.fileExists(atPath: outputURL.path) else {
       throw CameraError.unknown(message: "output directory does not exist at: \(outputURL.path)", cause: nil)
     }
@@ -56,28 +58,36 @@ extension ChunkedRecorder: AVAssetWriterDelegate {
 
   private func saveInitSegment(_ data: Data) {
     let url = outputURL.appendingPathComponent("init.mp4")
-    save(data: data, url: url)
-    onChunkReady(url: url, type: .initialization)
+    do {
+      try data.write(to: url)
+      onChunkReady(url: url, type: .initialization)
+    } catch {
+      ReactLogger.log(level: .error, message: "Failed to write init file \(url): \(error.localizedDescription)")
+      onError?(CameraError.capture(.fileError))
+    }
   }
 
   private func saveSegment(_ data: Data, report: AVAssetSegmentReport?) {
     let name = "\(chunkIndex).mp4"
     let url = outputURL.appendingPathComponent(name)
-    save(data: data, url: url)
-    let duration = report?
-      .trackReports
-      .filter { $0.mediaType == .video }
-      .first?
-      .duration
-    onChunkReady(url: url, type: .data(index: chunkIndex, duration: duration))
-    chunkIndex += 1
+    if save(data: data, url: url) {
+      let duration = report?
+        .trackReports
+        .filter { $0.mediaType == .video }
+        .first?
+        .duration
+      onChunkReady(url: url, type: .data(index: chunkIndex, duration: duration))
+      chunkIndex += 1
+    }
   }
 
-  private func save(data: Data, url: URL) {
+  private func save(data: Data, url: URL) -> Bool {
     do {
       try data.write(to: url)
+      return true
     } catch {
       ReactLogger.log(level: .error, message: "Unable to write \(url): \(error.localizedDescription)")
+      return false
     }
   }
 

package/ios/Core/RecordingSession.swift

@@ -74,12 +74,13 @@ class RecordingSession {
   init(outputDiretory: String,
        fileType: AVFileType,
        onChunkReady: @escaping ((ChunkedRecorder.Chunk) -> Void),
+       onChunkError: ((Error) -> Void)? = nil,
        completion: @escaping (RecordingSession, AVAssetWriter.Status, Error?) -> Void) throws {
     completionHandler = completion
 
     do {
       let outputURL = URL(fileURLWithPath: outputDiretory)
-      recorder = try ChunkedRecorder(outputURL: outputURL, onChunkReady: onChunkReady)
+      recorder = try ChunkedRecorder(outputURL: outputURL, onChunkReady: onChunkReady, onError: onChunkError)
       assetWriter = AVAssetWriter(contentType: UTType(fileType.rawValue)!)
       assetWriter.shouldOptimizeForNetworkUse = false
       assetWriter.outputFileTypeProfile = .mpeg4AppleHLS

package/src/VideoFile.ts

@@ -41,6 +41,17 @@ export interface RecordVideoOptions {
    * @default 'normal'
    */
   videoBitRate?: 'extra-low' | 'low' | 'normal' | 'high' | 'extra-high' | number
+  /**
+   * The stream segment type for recording on Android.
+   * - `FRAGMENTED_MP4`: HLS-compatible segments (init.mp4 + numbered segments)
+   * - `RB_CHUNKED_MP4`: Legacy chunked MP4 format
+   *
+   * iOS always uses FRAGMENTED_MP4 regardless of this setting.
+   *
+   * @platform android
+   * @default 'FRAGMENTED_MP4'
+   */
+  streamSegmentType?: 'FRAGMENTED_MP4' | 'RB_CHUNKED_MP4'
 }
 
 /**