如何在iPhone上添加视频文字 [英] how to add text on video in iPhone

问题描述

我想在MPMoviePlayerViewController播放的视频中添加一个文本或字符串，使其成为正在播放的视频的一部分。因此，当我在Facebook或Twitter上发布该视频时，文本必须显示在视频上方。

I want to add a text or string ON the video being played by MPMoviePlayerViewController in a way that it becomes part of the video being played. So that, when I post that video on Facebook or Twitter the text must be shown above the video.

为此，我尝试获取视频的所有帧然后在每个帧上写入文本，然后再制作所有这些帧的视频。但是这样，我遇到内存问题，它在设备上崩溃。

For this I have tried getting all the frames of the video and then write text on each of those frames and then again make a video of all those frames. But this way, I am getting memory issues and it crashes on the device.

    - (NSArray*)getVideoFramesFromMovieController:(MPMoviePlayerViewController*)mpMoviePlayerVC
{       NSLog(@"Getting frames from a video asset.");

    //  videoFrames = [NSMutableArray array];
    NSMutableArray *videoFrames = [NSMutableArray array];


    for(float i= 0; i <= mpMoviePlayerVC.moviePlayer.duration; )
    {
        UIImage *singleFrameImage = [mpMoviePlayerVC.moviePlayer thumbnailImageAtTime:i timeOption:MPMovieTimeOptionExact];



        [videoFrames addObject:singleFrameImage];

        NSLog(@"Got frame number : %d",[videoFrames count]);

        i = i + (1/self.frameRate) ;    //frame capturing duration i.e. 15fps  //self.frameRate

    }
    NSLog(@"Total frames: %d",[videoFrames count]);
    return [NSArray arrayWithArray:videoFrames];
}

上面的方法给了我所有的框架，我在所有这些文字上写了一个文字，说你好，然后制作所有这些帧的视频。

Method above gives me all the frames, i write a text on all those text, say "hello", and then make a video of all these frames.

    -(void)writeImageAsMovie:(NSArray *)array toPath:(NSString*)path size:(CGSize)size
{
    NSLog(@"Inside writeImageAsMovie method.");

    NSError *error              = nil;


    AVAssetWriter *videoWriter  = [[AVAssetWriter alloc] initWithURL:
                                  [NSURL fileURLWithPath:path] fileType:AVFileTypeMPEG4
                                                              error:&error];


    NSParameterAssert(videoWriter);

    NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                   AVVideoCodecH264, AVVideoCodecKey,
                                   [NSNumber numberWithInt:size.width], AVVideoWidthKey,   
                                   [NSNumber numberWithInt:size.height], AVVideoHeightKey,   
                                   nil];
    AVAssetWriterInput* writerInput = [[AVAssetWriterInput
                                        assetWriterInputWithMediaType:AVMediaTypeVideo
                                        outputSettings:videoSettings] retain];



    AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor
                                                     assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput
                                                     sourcePixelBufferAttributes:nil];


    NSParameterAssert(writerInput);
    NSParameterAssert([videoWriter canAddInput:writerInput]);
    [videoWriter addInput:writerInput];


    //Start a session:
    [videoWriter startWriting];
    [videoWriter startSessionAtSourceTime:kCMTimeZero];


    dispatch_queue_t    dispatchQueue = dispatch_queue_create("mediaInputQueue", NULL);
    int __block         frame = 0;

    [writerInput requestMediaDataWhenReadyOnQueue:dispatchQueue usingBlock:^{
        while ([writerInput isReadyForMoreMediaData])
        {
            NSLog(@"Total frames to be written: %d",[array count]);
            if(++frame >= [array count])   //total frames
            {
                [writerInput markAsFinished];
                [videoWriter finishWriting];
                [videoWriter release];
                break;
            }

            CVPixelBufferRef buffer = (CVPixelBufferRef)[self pixelBufferFromCGImage:[[array objectAtIndex:frame]CGImage] andSize:size];
            if (buffer)
            {
                if(![adaptor appendPixelBuffer:buffer withPresentationTime:CMTimeMake(frame, self.frameRate)])
                    NSLog(@"FAIL");
                else
                    NSLog(@"Success:%d", frame);
                CFRelease(buffer);
            }
        }
    }];

    NSLog(@"outside for loop");


    [self performSelector:@selector(waitTillVideoFinishes) withObject:nil afterDelay:20.0];
}

它在mac上工作正常，但由于内存在设备上崩溃问题。

It is working fine on the mac, but crashes on the device because of memory issues.

我也尝试了各种方法为视频上的文字添加水印但无法通过。
提前致谢。

I'hv also tried various ways to watermark the text on the video but could not get through. Thanks in advance.

推荐答案

此代码在视频上添加文字或字符串，保存视频后您将玩任何玩家。
此代码的最大优点是提供带声音的视频。

This code is add a text or string ON the video and after saving video you will play on any player. Most Advantage of this code is Provide video with sound.

#import <AVFoundation/AVFoundation.h>

-(void)MixVideoWithText
{
    AVURLAsset* videoAsset = [[AVURLAsset alloc]initWithURL:url options:nil];
    AVMutableComposition* mixComposition = [AVMutableComposition composition];

    AVMutableCompositionTrack *compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
    AVAssetTrack *clipVideoTrack = [[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
    AVMutableCompositionTrack *compositionAudioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
    AVAssetTrack *clipAudioTrack = [[videoAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
    //If you need audio as well add the Asset Track for audio here

    [compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) ofTrack:clipVideoTrack atTime:kCMTimeZero error:nil];
    [compositionAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, videoAsset.duration) ofTrack:clipAudioTrack atTime:kCMTimeZero error:nil];

    [compositionVideoTrack setPreferredTransform:[[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] preferredTransform]];

    CGSize sizeOfVideo=[videoAsset naturalSize];
    //NSLog(@"sizeOfVideo.width is %f",sizeOfVideo.width);
    //NSLog(@"sizeOfVideo.height is %f",sizeOfVideo.height);
    //TextLayer defines the text they want to add in Video

    CATextLayer *textOfvideo=[[CATextLayer alloc] init];
    textOfvideo.string=[NSString stringWithFormat:@"%@",text];//text is shows the text that you want add in video.
    [textOfvideo setFont:(__bridge CFTypeRef)([UIFont fontWithName:[NSString stringWithFormat:@"%@",fontUsed] size:13])];//fontUsed is the name of font
    [textOfvideo setFrame:CGRectMake(0, 0, sizeOfVideo.width, sizeOfVideo.height/6)];
    [textOfvideo setAlignmentMode:kCAAlignmentCenter];
    [textOfvideo setForegroundColor:[selectedColour CGColor]];


    CALayer *optionalLayer=[CALayer layer];
    [optionalL addSublayer:textOfvideo];
    optionalL.frame=CGRectMake(0, 0, sizeOfVideo.width, sizeOfVideo.height);
    [optionalL setMasksToBounds:YES];

    CALayer *parentLayer=[CALayer layer];
    CALayer *videoLayer=[CALayer layer];
    parentLayer.frame=CGRectMake(0, 0, sizeOfVideo.width, sizeOfVideo.height);
    videoLayer.frame=CGRectMake(0, 0, sizeOfVideo.width, sizeOfVideo.height);
    [parentLayer addSublayer:videoLayer];
    [parentLayer addSublayer:optionalLayer];

    AVMutableVideoComposition *videoComposition=[AVMutableVideoComposition videoComposition] ;
    videoComposition.frameDuration=CMTimeMake(1, 10);
    videoComposition.renderSize=sizeOfVideo;
    videoComposition.animationTool=[AVVideoCompositionCoreAnimationTool videoCompositionCoreAnimationToolWithPostProcessingAsVideoLayer:videoLayer inLayer:parentLayer];

    AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
    instruction.timeRange = CMTimeRangeMake(kCMTimeZero, [mixComposition duration]);
    AVAssetTrack *videoTrack = [[mixComposition tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
    AVMutableVideoCompositionLayerInstruction* layerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:videoTrack];
    instruction.layerInstructions = [NSArray arrayWithObject:layerInstruction];
    videoComposition.instructions = [NSArray arrayWithObject: instruction];

    NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)objectAtIndex:0];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd_HH-mm-ss"];
    NSString *destinationPath = [documentsDirectory stringByAppendingFormat:@"/utput_%@.mov", [dateFormatter stringFromDate:[NSDate date]]];

    AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetMediumQuality];
    exportSession.videoComposition=videoComposition;

    exportSession.outputURL = [NSURL fileURLWithPath:destinationPath];
    exportSession.outputFileType = AVFileTypeQuickTimeMovie;
    [exportSession exportAsynchronouslyWithCompletionHandler:^{
    switch (exportSession.status)
    {
        case AVAssetExportSessionStatusCompleted:
            NSLog(@"Export OK");
            if (UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(destinationPath)) {
                UISaveVideoAtPathToSavedPhotosAlbum(destinationPath, self, @selector(video:didFinishSavingWithError:contextInfo:), nil);
            }
            break;
        case AVAssetExportSessionStatusFailed:
            NSLog (@"AVAssetExportSessionStatusFailed: %@", exportSession.error);
            break;
        case AVAssetExportSessionStatusCancelled:
            NSLog(@"Export Cancelled");
            break;
    }
  }];
}

显示保存视频后的错误。

Shows the error they will come after saving video.

-(void) video: (NSString *) videoPath didFinishSavingWithError: (NSError *) error contextInfo: (void *) contextInfo 
{
    if(error)
        NSLog(@"Finished saving video with error: %@", error); 
}

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