我正在尝试通过iphone录制间隔拍摄视频。我已经让它用于慢动作(通过捕获最大帧),120 fps。
现在我试图颠倒逻辑以捕获可能的最少帧,以实现游戏中时光倒流功能。
代码流程如下:
从AVCaptureDevice的可用设备格式查询所有支持的帧范围。
检查帧速率是否低于或等于所需的20 fps且尺寸等于或大于1920 * 1080.
一切正常,但是当我按下记录时,我得到"AVCaptureMovieFileOutput - no active/enabled connections"
例外。我只使用提供的帧速率和范围之一,为什么我得到这个例外?
一切都适用于30 fps。
#define kTimelapseRequiredFPS = 20
#define kMinRequiredDimensions (1920*1080)
- (void)configureCameraForSlowMoRecording:(AVCaptureDevice *)currentCaptureDevice
{
[_captureSession beginConfiguration];
AVCaptureDeviceFormat *bestFormat = nil;
AVFrameRateRange *bestFrameRateRange = nil;
for ( AVCaptureDeviceFormat *format in [currentCaptureDevice formats] )
{
//NSLog(@"Format: %@", format);
CMFormatDescriptionRef videoInfo = [format formatDescription];
double videoWidth = CMVideoFormatDescriptionGetDimensions(videoInfo).width;
double videoHeight = CMVideoFormatDescriptionGetDimensions(videoInfo).height;
double dimensions = videoWidth * videoHeight;
for ( AVFrameRateRange *range in format.videoSupportedFrameRateRanges )
{
//NSLog(@"Range: %@", range);
if ((range.maxFrameRate <= kTimelapseRequiredFPS) && (dimensions >= kMinRequiredDimensions))
{
bestFormat = format;
bestFrameRateRange = range;
}
}
}
if ( bestFormat )
{
NSLog(@"Final format: %@, Final range %@", bestFormat, bestFrameRateRange);
if ( [currentCaptureDevice lockForConfiguration:NULL] == YES )
{
currentCaptureDevice.activeFormat = bestFormat;
currentCaptureDevice.activeVideoMinFrameDuration = bestFrameRateRange.minFrameDuration;
currentCaptureDevice.activeVideoMaxFrameDuration = bestFrameRateRange.minFrameDuration;
[currentCaptureDevice unlockForConfiguration];
}
}
[_captureSession commitConfiguration];
}
以下是20 fps的帧速率和范围的对数:
Format: <AVCaptureDeviceFormat: 0x1765f7a0 'vide'/'420v' 2592x1936, { 1- 20 fps}, fov:56.700, max zoom:153.00 (upscales @1.26), AF System:1, ISO:46.0-736.0, SS:0.000018-1.000000>
Range: <AVFrameRateRange: 0x176556d0 1 - 20>
Format: <AVCaptureDeviceFormat: 0x1765f750 'vide'/'420f' 2592x1936, { 1- 20 fps}, fov:56.700, max zoom:153.00 (upscales @1.26), AF System:1, ISO:46.0-736.0, SS:0.000018-1.000000>
Range: <AVFrameRateRange: 0x1750db10 1 - 20>
Format: <AVCaptureDeviceFormat: 0x1765f740 'vide'/'420v' 3264x2448, { 1- 20 fps}, fov:56.700, max zoom:153.00 (upscales @1.00), AF System:1, ISO:46.0-736.0, SS:0.000018-1.000000>
Range: <AVFrameRateRange: 0x1750dc80 1 - 20>
Format: <AVCaptureDeviceFormat: 0x1765f6f0 'vide'/'420f' 3264x2448, { 1- 20 fps}, fov:56.700, max zoom:153.00 (upscales @1.00), AF System:1, ISO:46.0-736.0, SS:0.000018-1.000000>
Range: <AVFrameRateRange: 0x1751a260 1 - 20>
答案 0 :(得分:0)
不确定这是否已经解决,但是我在努力使慢动作工作,并且不断获得"AVCaptureMovieFileOutput - no active/enabled connections"
(所以我真的很想知道你是如何让它工作的:D)。但无论如何我解决了它,这里有一些棘手的东西我认为可以解决你的问题:
activeFormat
之前设置了一些预设。原来iOS不会自动处理其他东西。我做的是在设置之前设置AVCaptureSession.Preset.hd1280x720
activeFormat
到120fps的那个。完成上述操作后,我开始Error Domain=AVFoundationErrorDomain Code=-11803 "Cannot Record" UserInfo=0x152e60 {NSLocalizedRecoverySuggestion=Try recording again., AVErrorRecordingSuccessfullyFinishedKey=false, NSLocalizedDescription=Cannot Record}
。我找不到任何可能的原因 - 连接很好,会话正在运行。所以我再次按下录制按钮,它开始录制(哇,真的吗?只是字面意思“再试一次”?)我猜iOS只是发脾气,不得不考虑更长一点记录。所以我添加了一个递归函数来给movieFileOutput
一些时间来记录。 (对不起,这是在斯威夫特)
fileprivate func startRecording(to moviePath: URL) {
sessionQueue.async {
self.movieFileOutput.startRecording(to: moviePath, recordingDelegate: self)
if self.movieFileOutput.isRecording {
self.sessionQueue.asyncAfter(deadline: .now() + self.duration) {
self.stopRecording()
}
} else {
self.startRecording(to: moviePath)
}
}
}
希望它会有所帮助(或者也许是其他只是像我一样偶然发现这个问题的人。)