我正在借助WWDC 2010 AVCamDemo 示例中的示例代码开发应用程序。在应用程序中，我需要从 iPhone 的前置摄像头录制视频，但由于我所在的地方没有新的 iPhone 4，我无法正确测试代码。
如果有人能提醒我是否朝着正确的方向前进，我将非常感激。我可以在我的 iPhone 3G（升级到 iOS 4.1）上测试的有限代码在我设置 时崩溃AVCaptureSession，如下面的代码所示：
- (void)recordVideo
{
NSLog(@"video recording on");
AVCaptureDevice *videoCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
AVCaptureDeviceInput *videoInput = [[AVCaptureDeviceInput alloc] initWithDevice:videoCaptureDevice error:nil];
AVCaptureMovieFileOutput *movieFileOutput = [[AVCaptureMovieFileOutput alloc] init];
[movieFileOutput release];
AVCaptureSession *session = [[AVCaptureSession alloc] init];
[session addInput:videoInput];
[session addOutput:movieFileOutput];
[self setSession:session]; // crashes
if (![session isRunning])
{
[self performSelector:@selector(startRecording) withObject:nil afterDelay:1.0];
[session startRunning];
}
}
- (void)startRecording
{
AVCaptureConnection *videoConnection = [playVideo connectionWithMediaType:AVMediaTypeVideo fromConnections:[[self movieFileOutput] connections]];
if ([videoConnection isVideoOrientationSupported]) {
[videoConnection setVideoOrientation:[self orientation]];
}
[[self movieFileOutput] startRecordingToOutputFileURL:[self tempFileURL]
recordingDelegate:self];
}
- (void) stopRecording
{
NSLog(@"stop recording");
[[self movieFileOutput] stopRecording];
}
- (NSURL *) tempFileURL
{
NSString *outputPath = [[NSString alloc] initWithFormat:@"%@%@", NSTemporaryDirectory(), @"output.mov"];
NSURL *outputURL = [[NSURL alloc] initFileURLWithPath:outputPath];
NSFileManager *fileManager = [NSFileManager defaultManager];
if ([fileManager fileExistsAtPath:outputPath]) {
NSLog(@"file saved");
}
[outputPath release];
return [outputURL autorelease];
}
+ (AVCaptureConnection *)connectionWithMediaType:(NSString *)mediaType fromConnections:(NSArray *)connections;
{
for ( AVCaptureConnection *connection in connections ) {
for ( AVCaptureInputPort *port in [connection inputPorts] ) {
if ( [[port mediaType] isEqual:mediaType] ) {
return [[connection retain] autorelease];
}
}
}
return nil;
}
- (void)captureOutput:(AVCaptureFileOutput *)captureOutput
didStartRecordingToOutputFileAtURL:(NSURL *)fileURL
fromConnections:(NSArray *)connections
{
}
- (void)captureOutput:(AVCaptureFileOutput *)captureOutput
didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL
fromConnections:(NSArray *)connections
error:(NSError *)error
{
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
if ([library videoAtPathIsCompatibleWithSavedPhotosAlbum:outputFileURL])
{
[library writeVideoAtPathToSavedPhotosAlbum:outputFileURL
completionBlock:^(NSURL *assetURL, NSError *error)];
}
[library release];
}