ios - 以编程方式在 iOS 中录制视频

Question

我正在尝试实现如下功能

Final Recorded Video = "从前置摄像头捕捉视频 + 从视频录制音频(我正在播放的视频视频播放器)"。

要了解更多信息，请参阅附加的屏幕截图。

使用下面给出的代码块:最后我得到的是一个没有音频的视频。

但我想尝试实现的是“最终录制的视频，它必须是组合:'从我的前置摄像头拍摄的视频 + 仅录制我正在播放的视频文件中的音频。'"

如何实现以上功能？

这是我的代码。

“录音”按钮点击方法如下:

-(void) startRecording
{
    [self initCaptureSession];

    NSURL *url = [NSURL fileURLWithPath:[[NSBundle mainBundle]
                                         pathForResource:@"video"
                                         ofType:@"mp4"]];
    [self playMovieAtURL:url];

    [self startVideoRecording];
}

“initCaptureSession”:使用这种方法，我使用前置摄像头录制视频“AVCaptureSession”

-(void) initCaptureSession
{
    NSLog(@"Setting up capture session");
    captureSession = [[AVCaptureSession alloc] init];

    NSLog(@"Adding video input");

    AVCaptureDevice *VideoDevice = [self frontFacingCameraIfAvailable];

    if (VideoDevice)
    {
        NSError *error;
        videoInputDevice = [AVCaptureDeviceInput deviceInputWithDevice:VideoDevice error:&error];
        if (!error)
        {
            if ([captureSession canAddInput:videoInputDevice])
            {
                [captureSession addInput:videoInputDevice];
            }
            else
            {
                NSLog(@"Couldn't add video input");
            }
        }
        else
        {
            NSLog(@"Couldn't create video input");
        }
    }
    else
    {
        NSLog(@"Couldn't create video capture device");
    }


    NSLog(@"Adding audio input");
    AVCaptureDevice *audioCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeMuxed];
    NSError *error = nil;
    AVCaptureDeviceInput *audioInput = [AVCaptureDeviceInput deviceInputWithDevice:audioCaptureDevice error:&error];
    if (audioInput)
    {
        [captureSession addInput:audioInput];
    }


    NSLog(@"Adding movie file output");
    movieFileOutput = [[AVCaptureMovieFileOutput alloc] init];

    movieFileOutput.minFreeDiskSpaceLimit = 1024 * 1024;    //<<SET MIN FREE SPACE IN BYTES FOR RECORDING TO CONTINUE ON A VOLUME

    if ([captureSession canAddOutput:movieFileOutput])
        [captureSession addOutput:movieFileOutput];

    [self CameraSetOutputProperties];           //(We call a method as it also has to be done after changing camera)

    NSLog(@"Setting image quality");
    [captureSession setSessionPreset:AVCaptureSessionPresetMedium];
    if ([captureSession canSetSessionPreset:AVCaptureSessionPreset640x480])     //Check size based configs are supported before setting them
        [captureSession setSessionPreset:AVCaptureSessionPreset640x480];

    [captureSession startRunning];
}

- (void) CameraSetOutputProperties
{
    AVCaptureConnection *CaptureConnection = nil;

    NSComparisonResult order = [[UIDevice currentDevice].systemVersion compare: @"5.0.0" options: NSNumericSearch];
    if (order == NSOrderedSame || order == NSOrderedDescending) {
        // OS version >= 5.0.0
        CaptureConnection = [movieFileOutput connectionWithMediaType:AVMediaTypeVideo];
    } else {
        // OS version < 5.0.0
        CaptureConnection = [self connectionWithMediaType:AVMediaTypeVideo fromConnections:[movieFileOutput connections]];
    }

    //Set landscape (if required)
    if ([CaptureConnection isVideoOrientationSupported])
    {
        AVCaptureVideoOrientation orientation =  AVCaptureVideoOrientationPortrait;// AVCaptureVideoOrientationLandscapeRight;      //<<<<<SET VIDEO ORIENTATION IF LANDSCAPE
        [CaptureConnection setVideoOrientation:orientation];
    }
 }

"-(void) playMovieAtURL: (NSURL*) theURL "通过使用这种方法我正在播放视频

-(void) playMovieAtURL: (NSURL*) theURL
{
player =
[[MPMoviePlayerController alloc] initWithContentURL: theURL];
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];

player.scalingMode = MPMovieScalingModeAspectFill;
player.controlStyle = MPMovieControlStyleNone;
[player prepareToPlay];

[[NSNotificationCenter defaultCenter]
 addObserver: self
 selector: @selector(myMovieFinishedCallback:)
 name: MPMoviePlayerPlaybackDidFinishNotification
 object: player];
player.view.frame=CGRectMake(10, 30, 300, 200);
[self.view addSubview:player.view];

[player play];
}

“startVideoRecording”使用这种方法我已经开始录制最终视频。

- (void) startVideoRecording
{
    //Create temporary URL to record to
    NSString *outputPath = [[NSString alloc] initWithFormat:@"%@%@", NSTemporaryDirectory(), @"output.mov"];
    NSURL *outputURL = [[NSURL alloc] initFileURLWithPath:outputPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    if ([fileManager fileExistsAtPath:outputPath])
    {
        NSError *error;
        if ([fileManager removeItemAtPath:outputPath error:&error] == NO)
        {
            //Error - handle if required
            NSLog(@"file remove error");
        }
    }
    //Start recording
    [movieFileOutput startRecordingToOutputFileURL:outputURL recordingDelegate:self];
}

- (void)captureOutput:(AVCaptureFileOutput *)captureOutput
didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL
      fromConnections:(NSArray *)connections
                error:(NSError *)error
{
    NSLog(@"didFinishRecordingToOutputFileAtURL - enter");

    BOOL RecordedSuccessfully = YES;
    if ([error code] != noErr)
    {
        // A problem occurred: Find out if the recording was successful.
        id value = [[error userInfo] objectForKey:AVErrorRecordingSuccessfullyFinishedKey];
        if (value)
        {
            RecordedSuccessfully = [value boolValue];
        }
    }
    if (RecordedSuccessfully)
    {
        //----- RECORDED SUCCESSFULLY -----
        NSLog(@"didFinishRecordingToOutputFileAtURL - success");
        ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
        if ([library videoAtPathIsCompatibleWithSavedPhotosAlbum:outputFileURL])
        {
            [library writeVideoAtPathToSavedPhotosAlbum:outputFileURL
                                        completionBlock:^(NSURL *assetURL, NSError *error)
             {
                 if (error)
                 {
                     NSLog(@"File save error");
                 }
                 else
                 {
                     recordedVideoURL=assetURL;
                 }
             }];
        }
        else
        {
            NSString *assetURL=[self copyFileToDocuments:outputFileURL];
            if(assetURL!=nil)
            {
                recordedVideoURL=[NSURL URLWithString:assetURL];
            }
        }
    }
}

Answer 1

//为以下方法添加一些额外的代码 “第一种方法”

  -(void) playMovieAtURL: (NSURL*) theURL

    {
       [player play];
       AVAudioSession *audioSession = [AVAudioSession sharedInstance];
       NSError *err = nil;
       [audioSession setCategory :AVAudioSessionCategoryPlayAndRecord error:&err];
     if(err)
      {
        NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo]     description]);
        return;
    }
       [audioSession setActive:YES error:&err];
       err = nil;
    if(err){
        NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
        return;
    }

       recordSetting = [[NSMutableDictionary alloc] init];

      [recordSetting setValue :[NSNumber numberWithInt:kAudioFormatAppleIMA4] forKey:AVFormatIDKey];
      [recordSetting setValue:[NSNumber numberWithFloat:16000.0] forKey:AVSampleRateKey];
      [recordSetting setValue:[NSNumber numberWithInt: 1] forKey:AVNumberOfChannelsKey];
      recorderFilePath = [NSString stringWithFormat:@"%@/MySound.caf", DOCUMENTS_FOLDER];
     NSLog(@"recorderFilePath: %@",recorderFilePath);
     audio_url = [NSURL fileURLWithPath:recorderFilePath];
    err = nil;
    NSData *audioData = [NSData dataWithContentsOfFile:[audio_url path] options: 0 error:&err];
    if(audioData)
    {
        NSFileManager *fm = [NSFileManager defaultManager];
        [fm removeItemAtPath:[audio_url path] error:&err];
    }

    err = nil;
    recorder = [[ AVAudioRecorder alloc] initWithURL:audio_url settings:recordSetting error:&err];
    if(!recorder)
    {
        NSLog(@"recorder: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
        UIAlertView *alert =
        [[UIAlertView alloc] initWithTitle: @"Warning"
                                   message: [err localizedDescription]
                                  delegate: nil
                         cancelButtonTitle:@"OK"
                         otherButtonTitles:nil];
        [alert show];
        return;
    }

    //prepare to record
    [recorder setDelegate:self];
    [recorder prepareToRecord];
    recorder.meteringEnabled = YES;

    BOOL audioHWAvailable = audioSession.inputAvailable;
    if (! audioHWAvailable)
    {
        UIAlertView *cantRecordAlert =
        [[UIAlertView alloc] initWithTitle: @"Warning"
                                   message: @"Audio input hardware not available"
                                  delegate: nil
                         cancelButtonTitle:@"OK"
                         otherButtonTitles:nil];
        [cantRecordAlert show];
        return;
    }


}

//第二种方法

-(void) stopVideoRecording

    {
    [player.view removeFromSuperview];
    [player stop];
    [movieFileOutput stopRecording];

    AVURLAsset* audioAsset = [[AVURLAsset alloc]initWithURL:audio_url options:nil];
    AVURLAsset* videoAsset = [[AVURLAsset alloc]initWithURL:outputURL options:nil];

    mixComposition = [AVMutableComposition composition];

    AVMutableCompositionTrack *compositionCommentaryTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio
                                                                                        preferredTrackID:kCMPersistentTrackID_Invalid];
    [compositionCommentaryTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, audioAsset.duration)
                                        ofTrack:[[audioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0]
                                         atTime:kCMTimeZero error:nil];

    AVMutableCompositionTrack *compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo
                                                                                   preferredTrackID:kCMPersistentTrackID_Invalid];
    [compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration)
                                   ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0]
                                    atTime:kCMTimeZero error:nil];

    AVAssetExportSession* _assetExport = [[AVAssetExportSession alloc] initWithAsset:mixComposition
                                                                          presetName:AVAssetExportPresetPassthrough];

    AVAssetTrack *videoTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
    [compositionVideoTrack setPreferredTransform:videoTrack.preferredTransform];
}

//最终播放视频

AVPlayerItem *playerItem = [AVPlayerItem playerItemWithAsset:mixComposition];
AVPlayer *player1 = [AVPlayer playerWithPlayerItem:playerItem];
AVPlayerLayer *playerLayer = [AVPlayerLayer playerLayerWithPlayer:player1];
[playerLayer setFrame:CGRectMake(0, 0, 320, 480)];
[[[self view] layer] addSublayer:playerLayer];
playerLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
[player1 play];
player1.actionAtItemEnd = AVPlayerActionAtItemEndNone;