WIP - implement ChunkedRecorder

- configure AVAssetWriter for fragmented mp4 output
- implement ChunkedRecorder to received chunk data via AVAssetWriterDelegate

package/ios/Core/ChunkedRecorder.swift

@@ -0,0 +1,70 @@
+//
+//  ChunkedRecorder.swift
+//  VisionCamera
+//
+//  Created by Rafael Bastos on 12/07/2024.
+//  Copyright © 2024 mrousavy. All rights reserved.
+//
+
+import Foundation
+import AVFoundation
+
+
+class ChunkedRecorder: NSObject {
+  
+  let outputURL: URL
+  
+  private var initSegment: Data?
+  private var index: Int = 0
+  
+  init(url: URL) throws {
+    outputURL = url
+    
+    guard FileManager.default.fileExists(atPath: outputURL.path) else {
+      throw CameraError.unknown(message: "output directory does not exist at: \(outputURL.path)", cause: nil)
+    }
+  }
+  
+}
+
+extension ChunkedRecorder: AVAssetWriterDelegate {
+  
+  func assetWriter(_ writer: AVAssetWriter, 
+                   didOutputSegmentData segmentData: Data,
+                   segmentType: AVAssetSegmentType,
+                   segmentReport: AVAssetSegmentReport?) {
+    
+    switch segmentType {
+    case .initialization:
+      saveInitSegment(segmentData)
+    case .separable:
+      saveSegment(segmentData)
+    @unknown default:
+      fatalError("Unknown AVAssetSegmentType!")
+    }
+  }
+  
+  private func saveInitSegment(_ data: Data) {     
+    initSegment = data
+  }
+  
+  private func saveSegment(_ data: Data) {
+    guard let initSegment else {
+      print("missing init segment")
+      return
+    }
+    
+    let file = String(format: "%06d.mp4", index)
+    index += 1
+    let url = outputURL.appendingPathComponent(file)
+    
+    do {
+      let outputData = initSegment + data
+      try outputData.write(to: url)
+      print("writing", data.count, "to", url)
+    } catch {
+      print("Error--->", error)
+    }
+  }
+  
+}

package/ios/Core/RecordingSession.swift

@@ -29,6 +29,7 @@ class RecordingSession {
   private let assetWriter: AVAssetWriter
   private var audioWriter: AVAssetWriterInput?
   private var videoWriter: AVAssetWriterInput?
+  private let recorder: ChunkedRecorder
   private let completionHandler: (RecordingSession, AVAssetWriter.Status, Error?) -> Void
 
   private var startTimestamp: CMTime?
@@ -49,7 +50,8 @@ class RecordingSession {
    Gets the file URL of the recorded video.
    */
   var url: URL {
-    return assetWriter.outputURL
+    // FIXME:
+    return recorder.outputURL
   }
 
   /**
@@ -76,8 +78,24 @@ class RecordingSession {
     completionHandler = completion
 
     do {
-      assetWriter = try AVAssetWriter(outputURL: url, fileType: fileType)
+      recorder = try ChunkedRecorder(url: url.deletingLastPathComponent())
+      assetWriter = AVAssetWriter(contentType: UTType(fileType.rawValue)!)
       assetWriter.shouldOptimizeForNetworkUse = false
+      assetWriter.outputFileTypeProfile = .mpeg4AppleHLS
+      assetWriter.preferredOutputSegmentInterval = CMTime(seconds: 6, preferredTimescale: 1)
+      
+      /*
+        Apple HLS fMP4 does not have an Edit List Box ('elst') in an initialization segment to remove
+        audio priming duration which advanced audio formats like AAC have, since the sample tables
+        are empty.  As a result, if the output PTS of the first non-fully trimmed audio sample buffer is
+        kCMTimeZero, the audio samples’ presentation time in segment files may be pushed forward by the
+        audio priming duration.  This may cause audio and video to be out of sync.  You should add a time
+        offset to all samples to avoid this situation.
+      */
+      let startTimeOffset = CMTime(value: 10, timescale: 1)
+      assetWriter.initialSegmentStartTime = startTimeOffset
+      
+      assetWriter.delegate = recorder
     } catch let error as NSError {
       throw CameraError.capture(.createRecorderError(message: error.description))
     }

package/ios/TestRecorder/ViewController.swift

@@ -39,7 +39,7 @@ class ViewController: UIViewController {
             
             cameraView.photo = true
             cameraView.video = true
-            cameraView.audio = true
+            cameraView.audio = false
             cameraView.isActive = true
             cameraView.cameraId = getCameraDeviceId() as NSString?
             cameraView.didSetProps([])
@@ -90,6 +90,7 @@ class ViewController: UIViewController {
         } else {
             cameraView.startRecording(
                 options: [
+                    "fileType": "mp4",
                     "videoCodec": "h265",
                 ]) { callback in
                     print("callback", callback)

package/ios/VisionCamera.xcodeproj/project.pbxproj

@@ -8,6 +8,8 @@
 
 /* Begin PBXBuildFile section */
 		B3AF8E862C410FB700CC198C /* ReactStubs.m in Sources */ = {isa = PBXBuildFile; fileRef = B3AF8E852C410FB700CC198C /* ReactStubs.m */; };
+		B3AF8E882C41159300CC198C /* ChunkedRecorder.swift in Sources */ = {isa = PBXBuildFile; fileRef = B3AF8E872C41159300CC198C /* ChunkedRecorder.swift */; };
+		B3AF8E892C41159300CC198C /* ChunkedRecorder.swift in Sources */ = {isa = PBXBuildFile; fileRef = B3AF8E872C41159300CC198C /* ChunkedRecorder.swift */; };
 		B3EF9F0D2C3FBD8300832EE7 /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = B3EF9F0C2C3FBD8300832EE7 /* AppDelegate.swift */; };
 		B3EF9F0F2C3FBD8300832EE7 /* SceneDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = B3EF9F0E2C3FBD8300832EE7 /* SceneDelegate.swift */; };
 		B3EF9F112C3FBD8300832EE7 /* ViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = B3EF9F102C3FBD8300832EE7 /* ViewController.swift */; };
@@ -165,6 +167,7 @@
 		B3AF8E832C410FB600CC198C /* TestRecorder-Bridging-Header.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "TestRecorder-Bridging-Header.h"; sourceTree = "<group>"; };
 		B3AF8E842C410FB700CC198C /* ReactStubs.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ReactStubs.h; sourceTree = "<group>"; };
 		B3AF8E852C410FB700CC198C /* ReactStubs.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = ReactStubs.m; sourceTree = "<group>"; };
+		B3AF8E872C41159300CC198C /* ChunkedRecorder.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ChunkedRecorder.swift; sourceTree = "<group>"; };
 		B3EF9F0A2C3FBD8300832EE7 /* TestRecorder.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = TestRecorder.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		B3EF9F0C2C3FBD8300832EE7 /* AppDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
 		B3EF9F0E2C3FBD8300832EE7 /* SceneDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SceneDelegate.swift; sourceTree = "<group>"; };
@@ -364,6 +367,7 @@
 				B88103E22AD7065C0087F063 /* CameraSessionDelegate.swift */,
 				B83D5EE629377117000AFD2F /* PreviewView.swift */,
 				B8DB3BC9263DC4D8004C18D7 /* RecordingSession.swift */,
+				B3AF8E872C41159300CC198C /* ChunkedRecorder.swift */,
 				B887515C25E0102000DB86D6 /* PhotoCaptureDelegate.swift */,
 				B84760DE2608F57D004C3180 /* CameraQueues.swift */,
 				B887518325E0102000DB86D6 /* CameraError.swift */,
@@ -636,6 +640,7 @@
 				B88977BE2B556DBA0095C92C /* AVCaptureDevice+minFocusDistance.swift in Sources */,
 				B80175EC2ABDEBD000E7DE90 /* ResizeMode.swift in Sources */,
 				B887519F25E0102000DB86D6 /* AVCaptureDevice.DeviceType+physicalDeviceDescriptor.swift in Sources */,
+				B3AF8E882C41159300CC198C /* ChunkedRecorder.swift in Sources */,
 				B88685ED2AD6A5E600E93869 /* CameraSession+CodeScanner.swift in Sources */,
 				B8207AAD2B0E5DD70002990F /* AVCaptureSession+synchronizeBuffer.swift in Sources */,
 				B8D22CDC2642DB4D00234472 /* AVAssetWriterInputPixelBufferAdaptor+initWithVideoSettings.swift in Sources */,
@@ -672,6 +677,7 @@
 				B3EF9F6A2C3FC46900832EE7 /* Promise.swift in Sources */,
 				B3EF9F4B2C3FC31E00832EE7 /* AVAssetWriterInputPixelBufferAdaptor+initWithVideoSettings.swift in Sources */,
 				B3EF9F5E2C3FC43000832EE7 /* AVCapturePhotoOutput.QualityPrioritization+descriptor.swift in Sources */,
+				B3AF8E892C41159300CC198C /* ChunkedRecorder.swift in Sources */,
 				B3EF9F5F2C3FC43000832EE7 /* AVAuthorizationStatus+descriptor.swift in Sources */,
 				B3EF9F602C3FC43000832EE7 /* AVCaptureDevice.FlashMode+descriptor.swift in Sources */,
 				B3EF9F612C3FC43000832EE7 /* AVFileType+descriptor.swift in Sources */,