[camera_avfoundation] fix sample times not being numeric after pause/resume. (flutter#6897)

Correctly initialise `_lastVideoSampleTime` and `_lastAudioSampleTime` before first use to avoid propagating invalid (non-numeric) values into methods like `appendPixelBuffer`.

Fixes flutter#132014

Author: misos1

packages/camera/camera_avfoundation/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.16+1
+
+* Fixes sample times not being numeric after pause/resume.
+
 ## 0.9.16
 
 * Converts Dart-to-host communcation to Pigeon.

packages/camera/camera_avfoundation/example/ios/RunnerTests/FLTCamSampleBufferTests.m

@@ -130,4 +130,72 @@ - (void)testDidOutputSampleBufferIgnoreAudioSamplesBeforeVideoSamples {
   CFRelease(audioSample);
 }
 
+- (void)testDidOutputSampleBufferSampleTimesMustBeNumericAfterPauseResume {
+  FLTCam *cam = FLTCreateCamWithCaptureSessionQueue(dispatch_queue_create("testing", NULL));
+  CMSampleBufferRef videoSample = FLTCreateTestSampleBuffer();
+  CMSampleBufferRef audioSample = FLTCreateTestAudioSampleBuffer();
+
+  id connectionMock = OCMClassMock([AVCaptureConnection class]);
+
+  id writerMock = OCMClassMock([AVAssetWriter class]);
+  OCMStub([writerMock alloc]).andReturn(writerMock);
+  OCMStub([writerMock initWithURL:OCMOCK_ANY fileType:OCMOCK_ANY error:[OCMArg setTo:nil]])
+      .andReturn(writerMock);
+  __block AVAssetWriterStatus status = AVAssetWriterStatusUnknown;
+  OCMStub([writerMock startWriting]).andDo(^(NSInvocation *invocation) {
+    status = AVAssetWriterStatusWriting;
+  });
+  OCMStub([writerMock status]).andDo(^(NSInvocation *invocation) {
+    [invocation setReturnValue:&status];
+  });
+
+  __block BOOL videoAppended = NO;
+  id adaptorMock = OCMClassMock([AVAssetWriterInputPixelBufferAdaptor class]);
+  OCMStub([adaptorMock assetWriterInputPixelBufferAdaptorWithAssetWriterInput:OCMOCK_ANY
+                                                  sourcePixelBufferAttributes:OCMOCK_ANY])
+      .andReturn(adaptorMock);
+  OCMStub([adaptorMock appendPixelBuffer:[OCMArg anyPointer] withPresentationTime:kCMTimeZero])
+      .ignoringNonObjectArgs()
+      .andDo(^(NSInvocation *invocation) {
+        CMTime presentationTime;
+        [invocation getArgument:&presentationTime atIndex:3];
+        XCTAssert(CMTIME_IS_NUMERIC(presentationTime));
+        videoAppended = YES;
+      });
+
+  __block BOOL audioAppended = NO;
+  id inputMock = OCMClassMock([AVAssetWriterInput class]);
+  OCMStub([inputMock assetWriterInputWithMediaType:OCMOCK_ANY outputSettings:OCMOCK_ANY])
+      .andReturn(inputMock);
+  OCMStub([inputMock isReadyForMoreMediaData]).andReturn(YES);
+  OCMStub([inputMock appendSampleBuffer:[OCMArg anyPointer]]).andDo(^(NSInvocation *invocation) {
+    CMSampleBufferRef sampleBuffer;
+    [invocation getArgument:&sampleBuffer atIndex:2];
+    CMTime sampleTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);
+    XCTAssert(CMTIME_IS_NUMERIC(sampleTime));
+    audioAppended = YES;
+  });
+
+  [cam
+      startVideoRecordingWithCompletion:^(FlutterError *_Nullable error) {
+      }
+                  messengerForStreaming:nil];
+
+  [cam pauseVideoRecording];
+  [cam resumeVideoRecording];
+
+  [cam captureOutput:cam.captureVideoOutput
+      didOutputSampleBuffer:videoSample
+             fromConnection:connectionMock];
+  [cam captureOutput:nil didOutputSampleBuffer:audioSample fromConnection:connectionMock];
+  [cam captureOutput:cam.captureVideoOutput
+      didOutputSampleBuffer:videoSample
+             fromConnection:connectionMock];
+  [cam captureOutput:nil didOutputSampleBuffer:audioSample fromConnection:connectionMock];
+  XCTAssert(videoAppended && audioAppended, @"Video or audio was not appended.");
+
+  CFRelease(videoSample);
+  CFRelease(audioSample);
+}
+
 @end

packages/camera/camera_avfoundation/ios/Classes/FLTCam.m

@@ -672,6 +672,10 @@ - (void)captureOutput:(AVCaptureOutput *)output
     if (_videoWriter.status != AVAssetWriterStatusWriting) {
       [_videoWriter startWriting];
       [_videoWriter startSessionAtSourceTime:currentSampleTime];
+      // fix sample times not being numeric when pause/resume happens before first sample buffer
+      // arrives https://github.com/flutter/flutter/issues/132014
+      _lastVideoSampleTime = currentSampleTime;
+      _lastAudioSampleTime = currentSampleTime;
     }
 
     if (output == _captureVideoOutput) {

packages/camera/camera_avfoundation/pubspec.yaml

@@ -2,7 +2,7 @@ name: camera_avfoundation
 description: iOS implementation of the camera plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/camera/camera_avfoundation
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.9.16
+version: 0.9.16+1
 
 environment:
   sdk: ^3.2.3