- (void)createNewVideoWithWaterMark:(NSURL *)videoPath

{

    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,  NSUserDomainMask,YES);

    NSString *ourDocumentPath =[documentPaths objectAtIndex:0];

    NSString *resultPath = [ourDocumentPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.mp4",@"resultVideo"]];

    // Delete old videos

    [self removeFileWithUrl:resultPath];

    

    NSError *error;

    AVURLAsset *asset = [AVURLAsset URLAssetWithURL:videoPath options:nil];

    AVAssetReader *readerAsset = [AVAssetReader assetReaderWithAsset:asset error:&error];

    AVAssetWriter *writerAsset = [AVAssetWriter assetWriterWithURL:[NSURL fileURLWithPath:resultPath] fileType:AVFileTypeMPEG4 error:&error];


    NSArray *videoTracks = [asset tracksWithMediaType:AVMediaTypeVideo];

    NSDictionary *videoSetting = @{(id)kCVPixelBufferPixelFormatTypeKey : [NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA], (id)kCVPixelBufferIOSurfacePropertiesKey : [NSDictionary dictionary]};

 

    AVAssetReaderVideoCompositionOutput *videoOutput  = [AVAssetReaderVideoCompositionOutput assetReaderVideoCompositionOutputWithVideoTracks:videoTracks videoSettings:videoSetting];

    AVAssetWriterInput *videoInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:[self videoCompressSettings]];

    

    if ([readerAsset canAddOutput:videoOutput]) {

        NSDateFormatter *formater = [[NSDateFormatter alloc] init];

        [formater setDateFormat:@" yyyy-MM-dd HH:mm:ss "];

        NSString *waterMarkTime = [formater stringFromDate:[NSDate date]];

        

        videoOutput.videoComposition = [self fixedCompositionWithAsset:asset];

        [readerAsset addOutput:videoOutput];

    }

    

    if ([writerAsset canAddInput:videoInput]) {

        [writerAsset addInput:videoInput];

    }

 

    // audio

    NSArray *audioTracks = [asset tracksWithMediaType:AVMediaTypeAudio];

    NSDictionary *audioSetting = @{AVFormatIDKey : [NSNumber numberWithUnsignedInt:kAudioFormatLinearPCM]};

    AVAssetReaderAudioMixOutput *audioOutput = [AVAssetReaderAudioMixOutput assetReaderAudioMixOutputWithAudioTracks:audioTracks audioSettings:audioSetting];

    AVAssetWriterInput *audioInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeAudio outputSettings:[self audioCompressSettings]];


    if ([readerAsset canAddOutput:audioOutput]) {

        [readerAsset addOutput:audioOutput];

    }


    if ([writerAsset canAddInput:audioInput]) {

        [writerAsset addInput:audioInput];

    }

    

    [writerAsset startWriting];

    [writerAsset startSessionAtSourceTime:kCMTimeZero];

    [readerAsset startReading];


    dispatch_queue_t videoQueue = dispatch_queue_create("Video Queue", DISPATCH_QUEUE_SERIAL);

    dispatch_queue_t audioQueue = dispatch_queue_create("Audio Queue", DISPATCH_QUEUE_SERIAL);

    dispatch_group_t group = dispatch_group_create();

    dispatch_group_enter(group);


    [videoInput requestMediaDataWhenReadyOnQueue:videoQueue usingBlock:^{

        while ([videoInput isReadyForMoreMediaData]) {

            CMSampleBufferRef sampleBuffer;

            if([readerAsset status] == AVAssetReaderStatusReading && (sampleBuffer = [videoOutput copyNextSampleBuffer])){

                BOOL result = [videoInput appendSampleBuffer:sampleBuffer];

                CFRelease(sampleBuffer);

                if(!result){

                    [readerAsset cancelReading];

                    break;

                }

            }else{

                [videoInput markAsFinished];

                dispatch_group_leave(group);

                break;

            }

        }

    }];

    

    dispatch_group_enter(group);

    

    [audioInput requestMediaDataWhenReadyOnQueue:audioQueue usingBlock:^{

        while ([audioInput isReadyForMoreMediaData]) {

            CMSampleBufferRef sampleBuffer;

            if ([readerAsset status] == AVAssetReaderStatusReading && (sampleBuffer = [audioOutput copyNextSampleBuffer])) {

                // AVAssetWriterStatusFailed (reason: Error Domain=AVFoundationErrorDomain Code=-11800 "这项操作无法完成" UserInfo={NSLocalizedFailureReason=发生未知错误（-12780）, NSLocalizedDescription=这项操作无法完成, NSUnderlyingError=0x302399a70 {Error Domain=NSOSStatusErrorDomain Code=-12780 "(null)"}})

                BOOL result = [audioInput appendSampleBuffer:sampleBuffer];

                CFRelease(sampleBuffer);

                if(!result){

                    [readerAsset cancelReading];

                    break;

                }

            } else {

                [audioInput markAsFinished];

                dispatch_group_leave(group);

                break;

            }

        }

    }];


    dispatch_group_notify(group, dispatch_get_main_queue(), ^{

    });

}


- (AVMutableVideoComposition *)fixedCompositionWithAsset:(AVAsset *)videoAsset

{

    AVAssetTrack *videoAssetTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] firstObject];

    NSUInteger degress = 0;

    if (videoAssetTrack) {

        CGAffineTransform t = videoAssetTrack.preferredTransform;

       if (t.a == 0 && t.b == 1.0 && t.c == -1.0 && t.d == 0) {

            // Portrait

            degress = 90;

        } else if(t.a == 0 && t.b == -1.0 && t.c == 1.0 && t.d == 0) {

            // PortraitUpsideDown

            degress = 270;

        } else if(t.a == 1.0 && t.b == 0 && t.c == 0 && t.d == 1.0) {

            // LandscapeRight

            degress = 0;

        } else if(t.a == -1.0 && t.b == 0 && t.c == 0 && t.d == -1.0) {

            // LandscapeLeft

            degress = 180;

        }

   }

    

    CGAffineTransform translateToCenter;

    CGAffineTransform mixedTransform;

    

    if (degress == 90) {

        translateToCenter = CGAffineTransformMakeTranslation(videoAssetTrack.naturalSize.height, 0.0);

        mixedTransform = CGAffineTransformRotate(translateToCenter,M_PI_2);

    } else if(degress == 180) {

        translateToCenter = CGAffineTransformMakeTranslation(videoAssetTrack.naturalSize.width, videoAssetTrack.naturalSize.height);

        mixedTransform = CGAffineTransformRotate(translateToCenter,M_PI);

    } else if(degress == 270) {

        translateToCenter = CGAffineTransformMakeTranslation(0.0, videoAssetTrack.naturalSize.width);

        mixedTransform = CGAffineTransformRotate(translateToCenter,M_PI_2*3.0);

    } else {

        translateToCenter = CGAffineTransformMakeTranslation(0.0, videoAssetTrack.naturalSize.width);

        mixedTransform = CGAffineTransformRotate(translateToCenter,0);

    }

    

    AVMutableVideoCompositionInstruction *mainInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];

    mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, videoAsset.duration);

    AVMutableVideoCompositionLayerInstruction *videolayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoAssetTrack];

    [videolayerInstruction setOpacity:0.0 atTime:videoAsset.duration];

    [videolayerInstruction setTransform:mixedTransform atTime:kCMTimeZero];

    mainInstruction.layerInstructions = [NSArray arrayWithObjects:videolayerInstruction,nil];

    AVMutableVideoComposition *mainCompositionInst = [AVMutableVideoComposition videoComposition];

    

    CGSize naturalSize = videoAssetTrack.naturalSize;

    float renderWidth, renderHeight;

    renderWidth = naturalSize.width;

    renderHeight = naturalSize.height;

    if (isnan(renderWidth) || renderWidth <= 0) {

        if (degress == 90 || degress == 270) {

            renderWidth = 1080.0;

        } else {

            renderWidth = 1920.0;

        }

    } else {

        if (degress == 90 || degress == 270) {

            renderWidth = naturalSize.height;

        }

    }

    

    if (isnan(renderHeight) || renderHeight <= 0) {

        if (degress == 90 || degress == 270) {

            renderHeight = 1920.0;

        } else {

            renderHeight = 1080.0;

        }

    } else {

        if (degress == 90 || degress == 270) {

            renderHeight = naturalSize.width;

        }

    }

    

    mainCompositionInst.renderSize = CGSizeMake(renderWidth, renderHeight);

    mainCompositionInst.instructions = [NSArray arrayWithObject:mainInstruction];

    mainCompositionInst.frameDuration = CMTimeMake(1, 30);


    CATextLayer *subtitleText = [[CATextLayer alloc] init];

    [subtitleText setFontSize:35];

    [subtitleText setFrame:CGRectMake(10, renderHeight-50, renderWidth, 50)];

    [subtitleText setString:@"content 12345"];

    subtitleText.contentsScale = [UIScreen mainScreen].scale;

    [subtitleText setForegroundColor:[[[UIColor whiteColor] colorWithAlphaComponent:0.8] CGColor]];

    

    CALayer *overlayLayer = [CALayer layer];

    [overlayLayer addSublayer:subtitleText];

    overlayLayer.frame = CGRectMake(0, 0, renderWidth, renderHeight);

    [overlayLayer setMasksToBounds:YES];

    

    CALayer *parentLayer = [CALayer layer];

    CALayer *videoLayer = [CALayer layer];

    parentLayer.frame = CGRectMake(0, 0, renderWidth, renderHeight);

    videoLayer.frame = CGRectMake(0, 0, renderWidth, renderHeight);

    [parentLayer addSublayer:videoLayer];

    [parentLayer addSublayer:overlayLayer];

    mainCompositionInst.animationTool = [AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];

    return mainCompositionInst;

}


- (NSDictionary *)audioCompressSettings

{

    AudioChannelLayout stereoChannelLayout = { .mChannelLayoutTag = kAudioChannelLayoutTag_Stereo,

        .mChannelBitmap = 0,

        .mNumberChannelDescriptions = 0};

    NSData *channelLayoutAsData = [NSData dataWithBytes:&stereoChannelLayout length:offsetof(AudioChannelLayout, mChannelDescriptions)];

    NSDictionary *audioCompressSettings = @{AVFormatIDKey:@(kAudioFormatMPEG4AAC),

                                            AVEncoderBitRateKey:@96000,

                                            AVSampleRateKey:@44100,

                                            AVChannelLayoutKey:channelLayoutAsData,

                                            AVNumberOfChannelsKey:@2};

    return  audioCompressSettings;

}