From fb2156ec397f573fc7beac56de6b8975f5831500 Mon Sep 17 00:00:00 2001
From: Thomas Coldwell <31568400+thomas-coldwell@users.noreply.github.com>
Date: Sat, 11 Jun 2022 11:15:24 +0200
Subject: [PATCH] fix: Asset Writer Video-Audio Sync (#1075)

* fix: Start asset writer session on first frame

* fix: Remove debug log

* fix: Reset dev team
---
 example/ios/Podfile.lock                      |  4 ++--
 .../project.pbxproj                           |  4 ++--
 ios/CameraView+RecordVideo.swift              |  4 ++--
 ios/RecordingSession.swift                    | 21 ++++++++-----------
 4 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/example/ios/Podfile.lock b/example/ios/Podfile.lock
index 4a70f21..5e0009f 100644
--- a/example/ios/Podfile.lock
+++ b/example/ios/Podfile.lock
@@ -324,7 +324,7 @@ PODS:
     - React
   - RNVectorIcons (8.1.0):
     - React-Core
-  - VisionCamera (2.13.0):
+  - VisionCamera (2.13.3):
     - React
     - React-callinvoker
     - React-Core
@@ -504,7 +504,7 @@ SPEC CHECKSUMS:
   RNScreens: 40a2cb40a02a609938137a1e0acfbf8fc9eebf19
   RNStaticSafeAreaInsets: 6103cf09647fa427186d30f67b0f5163c1ae8252
   RNVectorIcons: 31cebfcf94e8cf8686eb5303ae0357da64d7a5a4
-  VisionCamera: 9959a41d3edc36b37e8361a2e6cbc05714f0689b
+  VisionCamera: 7bcf3a81533a1c9ad13930804377ad13a03fcded
   Yoga: e7dc4e71caba6472ff48ad7d234389b91dadc280
 
 PODFILE CHECKSUM: 29b1752e05601e9867644e58ce0ed8b9106be6cb
diff --git a/example/ios/VisionCameraExample.xcodeproj/project.pbxproj b/example/ios/VisionCameraExample.xcodeproj/project.pbxproj
index cf83259..87eb3b3 100644
--- a/example/ios/VisionCameraExample.xcodeproj/project.pbxproj
+++ b/example/ios/VisionCameraExample.xcodeproj/project.pbxproj
@@ -456,7 +456,7 @@
 				COPY_PHASE_STRIP = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
-				"EXCLUDED_ARCHS[sdk=iphonesimulator*]" = "arm64 ";
+				"EXCLUDED_ARCHS[sdk=iphonesimulator*]" = "";
 				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_NO_COMMON_BLOCKS = YES;
@@ -517,7 +517,7 @@
 				COPY_PHASE_STRIP = YES;
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
-				"EXCLUDED_ARCHS[sdk=iphonesimulator*]" = "arm64 ";
+				"EXCLUDED_ARCHS[sdk=iphonesimulator*]" = "";
 				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
diff --git a/ios/CameraView+RecordVideo.swift b/ios/CameraView+RecordVideo.swift
index 7c1903b..799a611 100644
--- a/ios/CameraView+RecordVideo.swift
+++ b/ios/CameraView+RecordVideo.swift
@@ -140,9 +140,9 @@ extension CameraView: AVCaptureVideoDataOutputSampleBufferDelegate, AVCaptureAud
 
       // start recording session with or without audio.
       do {
-        try recordingSession.start()
+        try recordingSession.startAssetWriter()
       } catch let error as NSError {
-        callback.reject(error: .capture(.createRecorderError(message: "RecordingSession failed to start writing.")), cause: error)
+        callback.reject(error: .capture(.createRecorderError(message: "RecordingSession failed to start asset writer.")), cause: error)
         return
       }
       self.isRecording = true
diff --git a/ios/RecordingSession.swift b/ios/RecordingSession.swift
index 16a7ada..a13b548 100644
--- a/ios/RecordingSession.swift
+++ b/ios/RecordingSession.swift
@@ -32,6 +32,7 @@ class RecordingSession {
 
   private var initialTimestamp: CMTime?
   private var latestTimestamp: CMTime?
+  private var hasStartedWritingSession = false
   private var hasWrittenFirstVideoFrame = false
   private var isFinishing = false
 
@@ -111,7 +112,7 @@ class RecordingSession {
   /**
    Start the Asset Writer(s). If the AssetWriter failed to start, an error will be thrown.
    */
-  func start() throws {
+  func startAssetWriter() throws {
     ReactLogger.log(level: .info, message: "Starting Asset Writer(s)...")
 
     let success = assetWriter.startWriting()
@@ -119,10 +120,6 @@ class RecordingSession {
       ReactLogger.log(level: .error, message: "Failed to start Asset Writer(s)!")
       throw RecordingSessionError.failedToStartSession
     }
-
-    initialTimestamp = CMTime(seconds: CACurrentMediaTime(), preferredTimescale: 1_000_000_000)
-    assetWriter.startSession(atSourceTime: initialTimestamp!)
-    ReactLogger.log(level: .info, message: "Started RecordingSession at \(initialTimestamp!.seconds) seconds.")
   }
 
   /**
@@ -138,11 +135,6 @@ class RecordingSession {
       ReactLogger.log(level: .error, message: "Frame arrived, but sample buffer is not ready!")
       return
     }
-    guard let initialTimestamp = initialTimestamp else {
-      ReactLogger.log(level: .error,
-                      message: "A frame arrived, but initialTimestamp was nil. Is this RecordingSession running?")
-      return
-    }
 
     latestTimestamp = timestamp
 
@@ -161,10 +153,15 @@ class RecordingSession {
         ReactLogger.log(level: .error, message: "Failed to get the CVImageBuffer!")
         return
       }
+      // Start the writing session before we write the first video frame
+      if !hasStartedWritingSession {
+        assetWriter.startSession(atSourceTime: timestamp)
+        ReactLogger.log(level: .info, message: "Started RecordingSession at \(timestamp.seconds) seconds.")
+        hasStartedWritingSession = true
+      }
       bufferAdaptor.append(imageBuffer, withPresentationTime: timestamp)
       if !hasWrittenFirstVideoFrame {
         hasWrittenFirstVideoFrame = true
-        ReactLogger.log(level: .warning, message: "VideoWriter: First frame arrived \((initialTimestamp - timestamp).seconds) seconds late.")
       }
     case .audio:
       guard let audioWriter = audioWriter else {
@@ -174,7 +171,7 @@ class RecordingSession {
       if !audioWriter.isReadyForMoreMediaData {
         return
       }
-      if !hasWrittenFirstVideoFrame {
+      if !hasWrittenFirstVideoFrame || !hasStartedWritingSession {
         // first video frame has not been written yet, so skip this audio frame.
         return
       }