我正在开发基于视频的应用程序。根据我的要求，我有一个标题和描述文本，因此必须同时使用标题和描述文本创建两个5-10秒持续时间的视频。
我已经将文本转换为图像，然后将图像转换为视频，但是问题是我的视频持续时间几乎不到一秒钟。是否可以增加视频的持续时间？
这是我的代码：
func exportTextToImage(titleText: String){
let image = UIImage.imageWithText(titleText)
imageView.image = image
exportImageToVideo(image: image)
}
func exportImageToVideo(image: UIImage){
var uiImages = [UIImage]()
uiImages .append(image)
let settings = CXEImagesToVideo.videoSettings(codec: "640", width: (uiImages[0].cgImage?.width)!, height: (uiImages[0].cgImage?.height)!)
let movieMaker = CXEImagesToVideo(videoSettings: settings)
movieMaker.createMovieFrom(images: uiImages){ (fileURL:URL) in
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: fileURL)
}) { saved, error in
if saved {
let alertController = UIAlertController(title: "Your video was successfully saved", message: nil, preferredStyle: .alert)
let defaultAction = UIAlertAction(title: "OK", style: .default, handler: nil)
alertController.addAction(defaultAction)
self.present(alertController, animated: true, completion: nil)
}
}
}
}
这是我的参考班：
import Foundation
import AVFoundation
import UIKit
typealias CXEMovieMakerCompletion = (URL) -> Void
typealias CXEMovieMakerUIImageExtractor = (AnyObject) -> UIImage?
public class CXEImagesToVideo: NSObject{
var assetWriter:AVAssetWriter!
var writeInput:AVAssetWriterInput!
var bufferAdapter:AVAssetWriterInputPixelBufferAdaptor!
var videoSettings:[String : Any]!
var frameTime:CMTime!
var fileURL:URL!
var completionBlock: CXEMovieMakerCompletion?
var movieMakerUIImageExtractor:CXEMovieMakerUIImageExtractor?
public class func videoSettings(codec:String, width:Int, height:Int) -> [String: Any]{
if(Int(width) % 16 != 0){
print("warning: video settings width must be divisible by 16")
}
let videoSettings:[String: Any] = [AVVideoCodecKey: AVVideoCodecH264,
AVVideoWidthKey: width,
AVVideoHeightKey: height]
return videoSettings
}
public init(videoSettings: [String: Any]) {
super.init()
let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
let tempPath = paths[0] + "/exprotvideo.mp4"
if(FileManager.default.fileExists(atPath: tempPath)){
guard (try? FileManager.default.removeItem(atPath: tempPath)) != nil else {
print("remove path failed")
return
}
}
self.fileURL = URL(fileURLWithPath: tempPath)
self.assetWriter = try! AVAssetWriter(url: self.fileURL, fileType: AVFileTypeQuickTimeMovie)
self.videoSettings = videoSettings
self.writeInput = AVAssetWriterInput(mediaType: AVMediaTypeVideo, outputSettings: videoSettings)
assert(self.assetWriter.canAdd(self.writeInput), "add failed")
self.assetWriter.add(self.writeInput)
let bufferAttributes:[String: Any] = [kCVPixelBufferPixelFormatTypeKey as String: Int(kCVPixelFormatType_32ARGB)]
self.bufferAdapter = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: self.writeInput, sourcePixelBufferAttributes: bufferAttributes)
self.frameTime = CMTimeMake(700, 300);//when 2 images then duration will be 5 sec
CMTimeShow(self.frameTime);
}
func createMovieFrom(urls: [URL], withCompletion: @escaping CXEMovieMakerCompletion){
self.createMovieFromSource(images: urls as [AnyObject], extractor:{(inputObject:AnyObject) ->UIImage? in
return UIImage(data: try! Data(contentsOf: inputObject as! URL))}, withCompletion: withCompletion)
}
func createMovieFrom(images: [UIImage], withCompletion: @escaping CXEMovieMakerCompletion){
self.createMovieFromSource(images: images, extractor: {(inputObject:AnyObject) -> UIImage? in
return inputObject as? UIImage}, withCompletion: withCompletion)
}
func createMovieFromSource(images: [AnyObject], extractor: @escaping CXEMovieMakerUIImageExtractor, withCompletion: @escaping CXEMovieMakerCompletion){
self.completionBlock = withCompletion
self.assetWriter.startWriting()
/*let timeScale: Int32 = 600
let movieLength = TimeInterval(20)
let halfMovieLength = Float64(movieLength/2.0) // videoWriter assumes frame lengths are equal.
let startFrameTime = CMTimeMake(2, timeScale)
let endFrameTime = CMTimeMakeWithSeconds(halfMovieLength, timeScale)
self.assetWriter.startSession(atSourceTime: startFrameTime)*/
self.assetWriter.startSession(atSourceTime: kCMTimeZero)
let mediaInputQueue = DispatchQueue(label: "mediaInputQueue")
var i = 0
let frameNumber = images.count
self.writeInput.requestMediaDataWhenReady(on: mediaInputQueue){
while(true){
if(i >= frameNumber){
break
}
if (self.writeInput.isReadyForMoreMediaData){
var sampleBuffer:CVPixelBuffer?
autoreleasepool{
let img = extractor(images[i])
if img == nil{
i += 1
print("Warning: counld not extract one of the frames")
//continue
}
sampleBuffer = self.newPixelBufferFrom(cgImage: img!.cgImage!)
}
if (sampleBuffer != nil){
if(i == 0){
self.bufferAdapter.append(sampleBuffer!, withPresentationTime: kCMTimeZero)
}else{
let value = i - 1
let lastTime = CMTimeMake(Int64(value), self.frameTime.timescale)
let presentTime = CMTimeAdd(lastTime, self.frameTime)
self.bufferAdapter.append(sampleBuffer!, withPresentationTime: presentTime)
}
i = i + 1
}
}
}
self.writeInput.markAsFinished()
self.assetWriter.finishWriting {
DispatchQueue.main.sync {
self.completionBlock!(self.fileURL)
}
}
}
}
func newPixelBufferFrom(cgImage:CGImage) -> CVPixelBuffer?{
let options:[String: Any] = [kCVPixelBufferCGImageCompatibilityKey as String: true, kCVPixelBufferCGBitmapContextCompatibilityKey as String: true]
var pxbuffer:CVPixelBuffer?
let frameWidth = self.videoSettings[AVVideoWidthKey] as! Int
let frameHeight = self.videoSettings[AVVideoHeightKey] as! Int
let status = CVPixelBufferCreate(kCFAllocatorDefault, frameWidth, frameHeight, kCVPixelFormatType_32ARGB, options as CFDictionary?, &pxbuffer)
assert(status == kCVReturnSuccess && pxbuffer != nil, "newPixelBuffer failed")
CVPixelBufferLockBaseAddress(pxbuffer!, CVPixelBufferLockFlags(rawValue: 0))
let pxdata = CVPixelBufferGetBaseAddress(pxbuffer!)
let rgbColorSpace = CGColorSpaceCreateDeviceRGB()
let context = CGContext(data: pxdata, width: frameWidth, height: frameHeight, bitsPerComponent: 8, bytesPerRow: CVPixelBufferGetBytesPerRow(pxbuffer!), space: rgbColorSpace, bitmapInfo: CGImageAlphaInfo.noneSkipFirst.rawValue)
assert(context != nil, "context is nil")
context!.concatenate(CGAffineTransform.identity)
context!.draw(cgImage, in: CGRect(x: 0, y: 0, width: cgImage.width, height: cgImage.height))
CVPixelBufferUnlockBaseAddress(pxbuffer!, CVPixelBufferLockFlags(rawValue: 0))
return pxbuffer
}
}