录制视频上的iPhone水印。 [英] iPhone Watermark on recorded Video.

问题描述

在我的应用程序中，我需要捕获视频并在该视频上添加水印。水印应为文本（时间和注释）。我看到使用QTKitFrame工作的代码。但是我读到该框架不适用于iPhone。

In my Application I need to capture a video and Put a watermark on that video. The watermark should be Text(Time and Notes). I saw a code using "QTKit" Frame work. However I read that the framework is not available for iPhone.

先谢谢。

推荐答案

使用 AVFoundation 。我建议用 AVCaptureVideoDataOutput 抓取帧，然后用水印图像覆盖捕获的帧，最后将捕获和处理的帧写入文件用户 AVAssetWriter 。

Use AVFoundation. I would suggest grabbing frames with AVCaptureVideoDataOutput, then overlaying the captured frame with the watermark image, and finally writing captured and processed frames to a file user AVAssetWriter.

搜索堆栈溢出，有很多很棒的例子详细介绍了如何完成我提到的每一件事。我没有看到任何代码示例来说明你想要的效果，但是你应该可以很容易地混合和匹配。

Search around stack overflow, there are a ton of fantastic examples detailing how to do each of these things I have mentioned. I haven't seen any that give code examples for exactly the effect you would like, but you should be able to mix and match pretty easily.

编辑：

看看这些链接：

iPhone：AVCaptureSession捕获输出崩溃（AVCaptureVideoDataOutput） - 这篇文章可能仅仅包含相关代码的帮助。

iPhone: AVCaptureSession capture output crashing (AVCaptureVideoDataOutput) - this post might be helpful just by nature of containing relevant code.

AVCaptureDataOutput 将以 CMSampleBufferRef s的形式返回图像。
使用以下代码将它们转换为 CGImageRef s：

AVCaptureDataOutput will return images as CMSampleBufferRefs. Convert them to CGImageRefs using this code:

    - (CGImageRef) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer // Create a CGImageRef from sample buffer data
{

    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); 
    CVPixelBufferLockBaseAddress(imageBuffer,0);        // Lock the image buffer 

    uint8_t *baseAddress = (uint8_t *)CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0);   // Get information of the image 
    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer); 
    size_t width = CVPixelBufferGetWidth(imageBuffer); 
    size_t height = CVPixelBufferGetHeight(imageBuffer); 
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 

    CGContextRef newContext = CGBitmapContextCreate(baseAddress, width, height, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst); 
    CGImageRef newImage = CGBitmapContextCreateImage(newContext); 
    CGContextRelease(newContext); 

    CGColorSpaceRelease(colorSpace); 
    CVPixelBufferUnlockBaseAddress(imageBuffer,0); 
    /* CVBufferRelease(imageBuffer); */  // do not call this!

    return newImage;
}

从那里你将转换为UIImage，

From there you would convert to a UIImage,

  UIImage *img = [UIImage imageWithCGImage:yourCGImage];  

然后使用

[img drawInRect:CGRectMake(x,y,height,width)]; 

将帧绘制到上下文，在其上绘制水印的PNG，然后添加使用 AVAssetWriter 将处理后的图像处理为输出视频。我建议实时添加它们，这样你就不会用大量的UIImages来填充内存。

to draw the frame to a context, draw a PNG of the watermark over it, and then add the processed images to your output video using AVAssetWriter. I would suggest adding them in real time so you're not filling up memory with tons of UIImages.

如何将UIImage数组导出为电影？ - 这篇文章展示了如何将已经处理的UIImages添加到视频中给定的持续时间。

How do I export UIImage array as a movie? - this post shows how to add the UIImages you have processed to a video for a given duration.

这样可以帮助您顺利为视频添加水印。请记住练习良好的内存管理，因为以20-30fps的速度泄漏图像是使应用程序崩溃的好方法。

This should get you well on your way to watermarking your videos. Remember to practice good memory management, because leaking images that are coming in at 20-30fps is a great way to crash the app.

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