Question

在我的项目中，我需要在视频开始时捕获帧。我从代理中捕获它

"- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection＆＃34;，并使用"appendPixelBuffer:newPixBuffer withPresentationTime:tmpTime"保存修改后的帧。这些都没关系！但是，当我完成一次录制时，avassetwriter的状态可以更改为已完成，但mp4文件无法保存。

这是我的一些代码：

configueration：

-(void)configRecording:(NSURL*)fileUrl

{ NSError *错误;

_recordingFilePath = fileUrl;

NSDictionary *videoCleanApertureSettings = @{
                                             AVVideoCleanApertureWidthKey: [NSNumber numberWithFloat:SCREEN_WIDTH],
                                             AVVideoCleanApertureHeightKey: [NSNumber numberWithFloat:SCREEN_WIDTH],
                                             AVVideoCleanApertureHorizontalOffsetKey: [NSNumber numberWithInt:10],
                                             AVVideoCleanApertureVerticalOffsetKey: [NSNumber numberWithInt:10],
                                             };

NSDictionary *videoCompressionSettings = @{
                                           AVVideoAverageBitRateKey: [NSNumber numberWithFloat:2000000.0],
                                           AVVideoMaxKeyFrameIntervalKey: [NSNumber numberWithInteger:1],
                                           AVVideoProfileLevelKey: AVVideoProfileLevelH264Baseline30,
                                           AVVideoCleanApertureKey: videoCleanApertureSettings,
                                           };

NSDictionary* videoSetting = [NSDictionary dictionaryWithObjectsAndKeys:
                              AVVideoCodecH264, AVVideoCodecKey,
                              [NSNumber numberWithInt:SCREEN_WIDTH],AVVideoWidthKey,
                              [NSNumber numberWithInt:SCREEN_WIDTH],AVVideoHeightKey,
                              videoCompressionSettings,AVVideoCompressionPropertiesKey,
                              AVVideoScalingModeResizeAspectFill,AVVideoScalingModeKey,
                              nil];

_avassetWriter = [AVAssetWriter assetWriterWithURL:fileUrl fileType:AVFileTypeMPEG4 error:&error];

// Add the audio input
AudioChannelLayout acl;
bzero( &acl, sizeof(acl));
acl.mChannelLayoutTag = kAudioChannelLayoutTag_Mono;
NSDictionary* audioOutputSettings = [ NSDictionary dictionaryWithObjectsAndKeys:
                       [ NSNumber numberWithInt: kAudioFormatAppleLossless ], AVFormatIDKey,
                       [ NSNumber numberWithInt: 16 ], AVEncoderBitDepthHintKey,
                       [ NSNumber numberWithFloat: 44100.0 ], AVSampleRateKey,
                       [ NSNumber numberWithInt: 1 ], AVNumberOfChannelsKey,
                       [ NSData dataWithBytes: &acl length: sizeof( acl ) ], AVChannelLayoutKey,
                       nil ];

_avassetWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSetting];
_avassetWriterInput.expectsMediaDataInRealTime = YES;
_audioWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:audioOutputSettings];
_audioWriterInput.expectsMediaDataInRealTime = YES;
_avassetAdaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:_avassetWriterInput sourcePixelBufferAttributes:videoSetting];


if ([_avassetWriter canAddInput:_avassetWriterInput] ) {

    [_avassetWriter addInput:_avassetWriterInput];

}

if ([_avassetWriter canAddInput:_audioWriterInput]) {
    [_avassetWriter addInput:_audioWriterInput];
}

BOOL canOutput = [_avassetWriter canApplyOutputSettings:videoSetting forMediaType:AVFileTypeMPEG4];
NSLog(@"can out put := %d", canOutput);

}

这是我的开始录音功能：

[_ avassetWriter startWriting];
[_avassetWriter startSessionAtSourceTime：kCMTimeZero];

3.这是修改框架的方法：

 - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
    {
        CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);

        int faceTrackResult = [faceTracker startFacialTracking:pixelBuffer
                                             startFaceTracking:YES
                                             withFaceRectangle:_faceRect
                                                 withRollAngle:_rollAngle];

        CVPixelBufferRetain(pixelBuffer);
        dispatch_async(dispatch_get_main_queue(), ^{
            [_trackerView drawSceneWithBackground:pixelBuffer];
            CVPixelBufferRelease(pixelBuffer);
        });

        if (cameraView.isRecording == YES) {
            CMTime tmpTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer);
            [cameraView getLastRecordingTime:tmpTime];
            //开始捕捉视频帧
                CGImageRef curFrameRef = [cameraView getImageRef:self.trackerView.frame];
                CVPixelBufferRef newPixBuffer = [self pixelBufferFromCGImage:curFrameRef];


                if (cameraView.avassetWriter.status == AVAssetWriterStatusWriting && cameraView.isRecording == YES) {

                    BOOL result = [cameraView.avassetAdaptor appendPixelBuffer:newPixBuffer withPresentationTime:tmpTime];
                    NSLog(@"result := %d; status := %ld", result, (long)cameraView.avassetWriter.status);
                }
        }
    }

这是我的停止录制功能：

- （无效）stopRecording { WS（weakSelf）;

    [_avassetWriterInput markAsFinished];
    [_avassetWriter endSessionAtSourceTime: lastSimple_Time];
    if (_avassetWriter.status != AVAssetWriterStatusCompleted) {
        NSLog(@"error := %@", _avassetWriter.error);
    }

    self.isRecording = NO;

    [_avassetWriter finishWritingWithCompletionHandler:^{

        if (_avassetWriter.status == AVAssetWriterStatusFailed) {
            NSLog(@"error := %@", _avassetWriter.error);
        }

        if (weakSelf.recordDelegate && [weakSelf.recordDelegate respondsToSelector:@selector(finishRecording:)]) {
            [weakSelf.recordDelegate finishRecording:weakSelf.recordingFilePath];
        }
    }];
}

如何在录制时修改帧并保存更改，然后将视频保存为mp4文件？

0 个答案: