ios - 如何在 Swift 中将图像导出为视频？

Question

我正在用 Swift 制作一个应用程序(我有最新的 xcode 更新)，它必须从一些图像生成视频。
我从这个答案中得到了代码 How do I export UIImage array as a movie?
我这样调用函数:

let size = CGSize(width: 1280, height: 720)
let pathVideo = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
let percorsoVideo = pathVideo[0]
writeImagesAsMovie(arrayImmagini, videoPath: percorsoVideo+"/prova.mp4", videoSize: size, videoFPS: 1)

“arrayImmagini”的字面定义如下:

var arrayImmagini = [UIImage(imageLiteral: "Frames/turtle/turtle0.jpg"), UIImage(imageLiteral: "Frames/turtle/turtle1.jpg"), ...]

当我尝试运行代码时，我得到一个完全黑色的视频，xcode 给我这 2 个错误的次数是数组中图像数量的两倍:

Sep  5 09:24:15  Prova[1554] <Error>: CGBitmapContextCreate: invalid data bytes/row: should be at least 7680 for 8 integer bits/component, 3 components, kCGImageAlphaPremultipliedFirst.
Sep  5 09:24:15  Prova[1554] <Error>: CGContextDrawImage: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.

阅读有关 CGBitmapContextCreate 的文档，我尝试以不同的方式调用它:

func fillPixelBufferFromImage(image: UIImage, pixelBuffer: CVPixelBufferRef) {
    CVPixelBufferLockBaseAddress(pixelBuffer, 0)

    let pixelData = CVPixelBufferGetBaseAddress(pixelBuffer)
    let rgbColorSpace = CGColorSpaceCreateDeviceRGB()

    // Create CGBitmapContext
    let context = CGBitmapContextCreate(
        nil,
        Int(image.size.width),
        Int(image.size.height),
        8,
        0,
        rgbColorSpace,
        CGImageAlphaInfo.PremultipliedFirst.rawValue
    )

    // Draw image into context
    CGContextDrawImage(context, CGRectMake(0, 0, image.size.width, image.size.height), image.CGImage)

    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0)
}

代替:

func fillPixelBufferFromImage(image: UIImage, pixelBuffer: CVPixelBufferRef) {
    CVPixelBufferLockBaseAddress(pixelBuffer, 0)

    let pixelData = CVPixelBufferGetBaseAddress(pixelBuffer)
    let rgbColorSpace = CGColorSpaceCreateDeviceRGB()

    // Create CGBitmapContext
    let context = CGBitmapContextCreate(
        pixelData,
        Int(image.size.width),
        Int(image.size.height),
        8,
        CVPixelBufferGetBytesPerRow(pixelBuffer),
        rgbColorSpace,
        CGImageAlphaInfo.PremultipliedFirst.rawValue
    )

    // Draw image into context
    CGContextDrawImage(context, CGRectMake(0, 0, image.size.width, image.size.height), image.CGImage)

    CVPixelBufferUnlockBaseAddress(pixelBuffer, 0)
}

这让 xcode 不再给我错误，但我仍然看到黑色视频。
请帮助我，我是应用程序开发的新手，甚至是 AVFoundation 的新手，我不知道如何自己解决它。

谢谢!

Answer 1

在多次尝试完成这项工作后，我发现了问题所在。视频的大小不能小于图片的大小。
完成此操作后，一切正常:

let size = CGSize(width: 1920, height: 1280)