我有一个严重的问题：我有NSArray几个UIImage对象。我现在想做的是从那些UIImages. 但我不知道该怎么做。
我希望有人可以帮助我或向我发送一个代码片段，它可以做我想做的事情。
编辑：供将来参考 - 应用解决方案后，如果视频看起来失真，请确保您正在捕获的图像/区域的宽度是 16 的倍数。经过数小时的努力后在这里找到：
为什么我的 UIImages 电影会得到扭曲？
这是完整的解决方案（只需确保宽度是 16 的倍数）
http://codethink.no-ip.org/wordpress/archives/673
看看AVAssetWriter和AVFoundation 框架的其余部分。writer 有一个AVAssetWriterInput类型的输入，它又具有一个名为appendSampleBuffer:的方法，可让您将单个帧添加到视频流中。基本上你必须：
1）给作者接线：
NSError *error = nil;
AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:
[NSURL fileURLWithPath:somePath] fileType:AVFileTypeQuickTimeMovie
error:&error];
NSParameterAssert(videoWriter);
NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
AVVideoCodecH264, AVVideoCodecKey,
[NSNumber numberWithInt:640], AVVideoWidthKey,
[NSNumber numberWithInt:480], AVVideoHeightKey,
nil];
AVAssetWriterInput* writerInput = [[AVAssetWriterInput
assetWriterInputWithMediaType:AVMediaTypeVideo
outputSettings:videoSettings] retain]; //retain should be removed if ARC
NSParameterAssert(writerInput);
NSParameterAssert([videoWriter canAddInput:writerInput]);
[videoWriter addInput:writerInput];
2）开始一个会话：
[videoWriter startWriting];
[videoWriter startSessionAtSourceTime:…] //use kCMTimeZero if unsure
3）写一些示例：
// Or you can use AVAssetWriterInputPixelBufferAdaptor.
// That lets you feed the writer input data from a CVPixelBuffer
// that’s quite easy to create from a CGImage.
[writerInput appendSampleBuffer:sampleBuffer];
4) 结束会话：
[writerInput markAsFinished];
[videoWriter endSessionAtSourceTime:…]; //optional can call finishWriting without specifying endTime
[videoWriter finishWriting]; //deprecated in ios6
/*
[videoWriter finishWritingWithCompletionHandler:...]; //ios 6.0+
*/
你仍然需要填写很多空白，但我认为唯一真正困难的部分是从 a 获取像素缓冲区CGImage：
- (CVPixelBufferRef) newPixelBufferFromCGImage: (CGImageRef) image
{
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
[NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
nil];
CVPixelBufferRef pxbuffer = NULL;
CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, frameSize.width,
frameSize.height, kCVPixelFormatType_32ARGB, (CFDictionaryRef) options,
&pxbuffer);
NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);
CVPixelBufferLockBaseAddress(pxbuffer, 0);
void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);
NSParameterAssert(pxdata != NULL);
CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pxdata, frameSize.width,
frameSize.height, 8, 4*frameSize.width, rgbColorSpace,
kCGImageAlphaNoneSkipFirst);
NSParameterAssert(context);
CGContextConcatCTM(context, frameTransform);
CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image),
CGImageGetHeight(image)), image);
CGColorSpaceRelease(rgbColorSpace);
CGContextRelease(context);
CVPixelBufferUnlockBaseAddress(pxbuffer, 0);
return pxbuffer;
}
frameSize是CGSize描述您的目标帧大小frameTransform的一个CGAffineTransform，它允许您在将图像绘制成帧时对其进行转换。
上周我开始编写 iOS 代码以从图像生成视频。我有一点 AVFoundation 经验，但从未听说过 CVPixelBuffer。我在此页面和此处遇到了答案。花了好几天的时间来剖析所有内容，然后以一种对我的大脑有意义的方式在 Swift 中将它们重新组合在一起。下面是我想出的。
注意：如果您将以下所有代码复制/粘贴到单个 Swift 文件中，它应该可以编译。你只需要调整loadImages()和RenderSettings值。
在这里，我将所有与导出相关的设置分组到一个RenderSettings结构中。
import AVFoundation
import UIKit
import Photos
struct RenderSettings {
var size : CGSize = .zero
var fps: Int32 = 6 // frames per second
var avCodecKey = AVVideoCodecType.h264
var videoFilename = "render"
var videoFilenameExt = "mp4"
var outputURL: URL {
// Use the CachesDirectory so the rendered video file sticks around as long as we need it to.
// Using the CachesDirectory ensures the file won't be included in a backup of the app.
let fileManager = FileManager.default
if let tmpDirURL = try? fileManager.url(for: .cachesDirectory, in: .userDomainMask, appropriateFor: nil, create: true) {
return tmpDirURL.appendingPathComponent(videoFilename).appendingPathExtension(videoFilenameExt)
}
fatalError("URLForDirectory() failed")
}
该类ImageAnimator了解您的图像并使用VideoWriter该类执行渲染。这个想法是将视频内容代码与低级 AVFoundation 代码分开。我还在saveToLibrary()这里添加了一个类函数，它在链的末尾被调用以将视频保存到照片库。
class ImageAnimator {
// Apple suggests a timescale of 600 because it's a multiple of standard video rates 24, 25, 30, 60 fps etc.
static let kTimescale: Int32 = 600
let settings: RenderSettings
let videoWriter: VideoWriter
var images: [UIImage]!
var frameNum = 0
class func saveToLibrary(videoURL: URL) {
PHPhotoLibrary.requestAuthorization { status in
guard status == .authorized else { return }
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: videoURL)
}) { success, error in
if !success {
print("Could not save video to photo library:", error)
}
}
}
}
class func removeFileAtURL(fileURL: URL) {
do {
try FileManager.default.removeItem(atPath: fileURL.path)
}
catch _ as NSError {
// Assume file doesn't exist.
}
}
init(renderSettings: RenderSettings) {
settings = renderSettings
videoWriter = VideoWriter(renderSettings: settings)
//images = loadImages()
}
func render(completion: (()->Void)?) {
// The VideoWriter will fail if a file exists at the URL, so clear it out first.
ImageAnimator.removeFileAtURL(fileURL: settings.outputURL)
videoWriter.start()
videoWriter.render(appendPixelBuffers: appendPixelBuffers) {
ImageAnimator.saveToLibrary(videoURL: self.settings.outputURL)
completion?()
}
}
// This is the callback function for VideoWriter.render()
func appendPixelBuffers(writer: VideoWriter) -> Bool {
let frameDuration = CMTimeMake(value: Int64(ImageAnimator.kTimescale / settings.fps), timescale: ImageAnimator.kTimescale)
while !images.isEmpty {
if writer.isReadyForData == false {
// Inform writer we have more buffers to write.
return false
}
let image = images.removeFirst()
let presentationTime = CMTimeMultiply(frameDuration, multiplier: Int32(frameNum))
let success = videoWriter.addImage(image: image, withPresentationTime: presentationTime)
if success == false {
fatalError("addImage() failed")
}
frameNum += 1
}
// Inform writer all buffers have been written.
return true
}
该VideoWriter课程完成所有 AVFoundation 繁重的工作。AVAssetWriter它主要是对and的包装AVAssetWriterInput。它还包含不是我编写的花哨的代码，它知道如何将图像转换为CVPixelBuffer.
class VideoWriter {
let renderSettings: RenderSettings
var videoWriter: AVAssetWriter!
var videoWriterInput: AVAssetWriterInput!
var pixelBufferAdaptor: AVAssetWriterInputPixelBufferAdaptor!
var isReadyForData: Bool {
return videoWriterInput?.isReadyForMoreMediaData ?? false
}
class func pixelBufferFromImage(image: UIImage, pixelBufferPool: CVPixelBufferPool, size: CGSize) -> CVPixelBuffer {
var pixelBufferOut: CVPixelBuffer?
let status = CVPixelBufferPoolCreatePixelBuffer(kCFAllocatorDefault, pixelBufferPool, &pixelBufferOut)
if status != kCVReturnSuccess {
fatalError("CVPixelBufferPoolCreatePixelBuffer() failed")
}
let pixelBuffer = pixelBufferOut!
CVPixelBufferLockBaseAddress(pixelBuffer, CVPixelBufferLockFlags(rawValue: 0))
let data = CVPixelBufferGetBaseAddress(pixelBuffer)
let rgbColorSpace = CGColorSpaceCreateDeviceRGB()
let context = CGContext(data: data, width: Int(size.width), height: Int(size.height),
bitsPerComponent: 8, bytesPerRow: CVPixelBufferGetBytesPerRow(pixelBuffer), space: rgbColorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedFirst.rawValue)
context!.clear(CGRect(x:0,y: 0,width: size.width,height: size.height))
let horizontalRatio = size.width / image.size.width
let verticalRatio = size.height / image.size.height
//aspectRatio = max(horizontalRatio, verticalRatio) // ScaleAspectFill
let aspectRatio = min(horizontalRatio, verticalRatio) // ScaleAspectFit
let newSize = CGSize(width: image.size.width * aspectRatio, height: image.size.height * aspectRatio)
let x = newSize.width < size.width ? (size.width - newSize.width) / 2 : 0
let y = newSize.height < size.height ? (size.height - newSize.height) / 2 : 0
context?.draw(image.cgImage!, in: CGRect(x:x,y: y, width: newSize.width, height: newSize.height))
CVPixelBufferUnlockBaseAddress(pixelBuffer, CVPixelBufferLockFlags(rawValue: 0))
return pixelBuffer
}
init(renderSettings: RenderSettings) {
self.renderSettings = renderSettings
}
func start() {
let avOutputSettings: [String: Any] = [
AVVideoCodecKey: renderSettings.avCodecKey,
AVVideoWidthKey: NSNumber(value: Float(renderSettings.size.width)),
AVVideoHeightKey: NSNumber(value: Float(renderSettings.size.height))
]
func createPixelBufferAdaptor() {
let sourcePixelBufferAttributesDictionary = [
kCVPixelBufferPixelFormatTypeKey as String: NSNumber(value: kCVPixelFormatType_32ARGB),
kCVPixelBufferWidthKey as String: NSNumber(value: Float(renderSettings.size.width)),
kCVPixelBufferHeightKey as String: NSNumber(value: Float(renderSettings.size.height))
]
pixelBufferAdaptor = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: videoWriterInput,
sourcePixelBufferAttributes: sourcePixelBufferAttributesDictionary)
}
func createAssetWriter(outputURL: URL) -> AVAssetWriter {
guard let assetWriter = try? AVAssetWriter(outputURL: outputURL, fileType: AVFileType.mp4) else {
fatalError("AVAssetWriter() failed")
}
guard assetWriter.canApply(outputSettings: avOutputSettings, forMediaType: AVMediaType.video) else {
fatalError("canApplyOutputSettings() failed")
}
return assetWriter
}
videoWriter = createAssetWriter(outputURL: renderSettings.outputURL)
videoWriterInput = AVAssetWriterInput(mediaType: AVMediaType.video, outputSettings: avOutputSettings)
if videoWriter.canAdd(videoWriterInput) {
videoWriter.add(videoWriterInput)
}
else {
fatalError("canAddInput() returned false")
}
// The pixel buffer adaptor must be created before we start writing.
createPixelBufferAdaptor()
if videoWriter.startWriting() == false {
fatalError("startWriting() failed")
}
videoWriter.startSession(atSourceTime: CMTime.zero)
precondition(pixelBufferAdaptor.pixelBufferPool != nil, "nil pixelBufferPool")
}
func render(appendPixelBuffers: ((VideoWriter)->Bool)?, completion: (()->Void)?) {
precondition(videoWriter != nil, "Call start() to initialze the writer")
let queue = DispatchQueue(label: "mediaInputQueue")
videoWriterInput.requestMediaDataWhenReady(on: queue) {
let isFinished = appendPixelBuffers?(self) ?? false
if isFinished {
self.videoWriterInput.markAsFinished()
self.videoWriter.finishWriting() {
DispatchQueue.main.async {
completion?()
}
}
}
else {
// Fall through. The closure will be called again when the writer is ready.
}
}
}
func addImage(image: UIImage, withPresentationTime presentationTime: CMTime) -> Bool {
precondition(pixelBufferAdaptor != nil, "Call start() to initialze the writer")
let pixelBuffer = VideoWriter.pixelBufferFromImage(image: image, pixelBufferPool: pixelBufferAdaptor.pixelBufferPool!, size: renderSettings.size)
return pixelBufferAdaptor.append(pixelBuffer, withPresentationTime: presentationTime)
}
一切就绪后，这就是您的 3 条神奇线：
let settings = RenderSettings()
let imageAnimator = ImageAnimator(renderSettings: settings)
imageAnimator.render() {
print("yes")
}
这是 Objective-C 在 iOS8 上的最新工作代码。
我们必须对@Zoul 的上述答案进行各种调整，以使其在最新版本的 Xcode 和 iOS8 上运行。这是我们完整的工作代码，它获取一组 UIImage，将它们制作成 .mov 文件，将其保存到临时目录，然后将其移动到相机胶卷。我们从多个不同的帖子中组装了代码以使其正常工作。我们已经强调了我们必须解决的陷阱才能让代码在我们的评论中正常工作。
(1) 创建 UIImages 的集合
[self saveMovieToLibrary]
- (IBAction)saveMovieToLibrary
{
// You just need the height and width of the video here
// For us, our input and output video was 640 height x 480 width
// which is what we get from the iOS front camera
ATHSingleton *singleton = [ATHSingleton singletons];
int height = singleton.screenHeight;
int width = singleton.screenWidth;
// You can save a .mov or a .mp4 file
//NSString *fileNameOut = @"temp.mp4";
NSString *fileNameOut = @"temp.mov";
// We chose to save in the tmp/ directory on the device initially
NSString *directoryOut = @"tmp/";
NSString *outFile = [NSString stringWithFormat:@"%@%@",directoryOut,fileNameOut];
NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:[NSString stringWithFormat:outFile]];
NSURL *videoTempURL = [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@%@", NSTemporaryDirectory(), fileNameOut]];
// WARNING: AVAssetWriter does not overwrite files for us, so remove the destination file if it already exists
NSFileManager *fileManager = [NSFileManager defaultManager];
[fileManager removeItemAtPath:[videoTempURL path] error:NULL];
// Create your own array of UIImages
NSMutableArray *images = [NSMutableArray array];
for (int i=0; i<singleton.numberOfScreenshots; i++)
{
// This was our routine that returned a UIImage. Just use your own.
UIImage *image =[self uiimageFromCopyOfPixelBuffersUsingIndex:i];
// We used a routine to write text onto every image
// so we could validate the images were actually being written when testing. This was it below.
image = [self writeToImage:image Text:[NSString stringWithFormat:@"%i",i ]];
[images addObject:image];
}
// If you just want to manually add a few images - here is code you can uncomment
// NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:[NSString stringWithFormat:@"Documents/movie.mp4"]];
// NSArray *images = [[NSArray alloc] initWithObjects:
// [UIImage imageNamed:@"add_ar.png"],
// [UIImage imageNamed:@"add_ja.png"],
// [UIImage imageNamed:@"add_ru.png"],
// [UIImage imageNamed:@"add_ru.png"],
// [UIImage imageNamed:@"add_ar.png"],
// [UIImage imageNamed:@"add_ja.png"],
// [UIImage imageNamed:@"add_ru.png"],
// [UIImage imageNamed:@"add_ar.png"],
// [UIImage imageNamed:@"add_en.png"], nil];
[self writeImageAsMovie:images toPath:path size:CGSizeMake(height, width)];
}
这是创建 AssetWriter 并向其添加图像以进行写入的主要方法。
(2) 连接一个 AVAssetWriter
-(void)writeImageAsMovie:(NSArray *)array toPath:(NSString*)path size:(CGSize)size
{
NSError *error = nil;
// FIRST, start up an AVAssetWriter instance to write your video
// Give it a destination path (for us: tmp/temp.mov)
AVAssetWriter *videoWriter = [[AVAssetWriter alloc] initWithURL:[NSURL fileURLWithPath:path]
fileType:AVFileTypeQuickTimeMovie
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];
AVAssetWriterInputPixelBufferAdaptor *adaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:writerInput
sourcePixelBufferAttributes:nil];
NSParameterAssert(writerInput);
NSParameterAssert([videoWriter canAddInput:writerInput]);
[videoWriter addInput:writerInput];
(3) 开始一个写作会话（注意：方法从上面继续）
//Start a SESSION of writing.
// After you start a session, you will keep adding image frames
// until you are complete - then you will tell it you are done.
[videoWriter startWriting];
// This starts your video at time = 0
[videoWriter startSessionAtSourceTime:kCMTimeZero];
CVPixelBufferRef buffer = NULL;
// This was just our utility class to get screen sizes etc.
ATHSingleton *singleton = [ATHSingleton singletons];
int i = 0;
while (1)
{
// Check if the writer is ready for more data, if not, just wait
if(writerInput.readyForMoreMediaData){
CMTime frameTime = CMTimeMake(150, 600);
// CMTime = Value and Timescale.
// Timescale = the number of tics per second you want
// Value is the number of tics
// For us - each frame we add will be 1/4th of a second
// Apple recommend 600 tics per second for video because it is a
// multiple of the standard video rates 24, 30, 60 fps etc.
CMTime lastTime=CMTimeMake(i*150, 600);
CMTime presentTime=CMTimeAdd(lastTime, frameTime);
if (i == 0) {presentTime = CMTimeMake(0, 600);}
// This ensures the first frame starts at 0.
if (i >= [array count])
{
buffer = NULL;
}
else
{
// This command grabs the next UIImage and converts it to a CGImage
buffer = [self pixelBufferFromCGImage:[[array objectAtIndex:i] CGImage]];
}
if (buffer)
{
// Give the CGImage to the AVAssetWriter to add to your video
[adaptor appendPixelBuffer:buffer withPresentationTime:presentTime];
i++;
}
else
{
(4) 完成会话（注：方法从上继续）
//Finish the session:
// This is important to be done exactly in this order
[writerInput markAsFinished];
// WARNING: finishWriting in the solution above is deprecated.
// You now need to give a completion handler.
[videoWriter finishWritingWithCompletionHandler:^{
NSLog(@"Finished writing...checking completion status...");
if (videoWriter.status != AVAssetWriterStatusFailed && videoWriter.status == AVAssetWriterStatusCompleted)
{
NSLog(@"Video writing succeeded.");
// Move video to camera roll
// NOTE: You cannot write directly to the camera roll.
// You must first write to an iOS directory then move it!
NSURL *videoTempURL = [NSURL fileURLWithPath:[NSString stringWithFormat:@"%@", path]];
[self saveToCameraRoll:videoTempURL];
} else
{
NSLog(@"Video writing failed: %@", videoWriter.error);
}
}]; // end videoWriter finishWriting Block
CVPixelBufferPoolRelease(adaptor.pixelBufferPool);
NSLog (@"Done");
break;
}
}
}
}
(5) 将您的 UIImages 转换为 CVPixelBufferRef
此方法将为您提供 AssetWriter 所需的 CV 像素缓冲区引用。这是从您从 UIImage（上图）获得的 CGImageRef 获得的。
- (CVPixelBufferRef) pixelBufferFromCGImage: (CGImageRef) image
{
// This again was just our utility class for the height & width of the
// incoming video (640 height x 480 width)
ATHSingleton *singleton = [ATHSingleton singletons];
int height = singleton.screenHeight;
int width = singleton.screenWidth;
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey,
[NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey,
nil];
CVPixelBufferRef pxbuffer = NULL;
CVReturn status = CVPixelBufferCreate(kCFAllocatorDefault, width,
height, kCVPixelFormatType_32ARGB, (__bridge CFDictionaryRef) options,
&pxbuffer);
NSParameterAssert(status == kCVReturnSuccess && pxbuffer != NULL);
CVPixelBufferLockBaseAddress(pxbuffer, 0);
void *pxdata = CVPixelBufferGetBaseAddress(pxbuffer);
NSParameterAssert(pxdata != NULL);
CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pxdata, width,
height, 8, 4*width, rgbColorSpace,
kCGImageAlphaNoneSkipFirst);
NSParameterAssert(context);
CGContextConcatCTM(context, CGAffineTransformMakeRotation(0));
CGContextDrawImage(context, CGRectMake(0, 0, CGImageGetWidth(image),
CGImageGetHeight(image)), image);
CGColorSpaceRelease(rgbColorSpace);
CGContextRelease(context);
CVPixelBufferUnlockBaseAddress(pxbuffer, 0);
return pxbuffer;
}
(6) 将您的视频移动到相机胶卷 因为 AVAssetWriter 不能直接写入相机胶卷，这会将视频从“tmp/temp.mov”（或您在上面命名的任何文件名）移动到相机胶卷。
- (void) saveToCameraRoll:(NSURL *)srcURL
{
NSLog(@"srcURL: %@", srcURL);
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
ALAssetsLibraryWriteVideoCompletionBlock videoWriteCompletionBlock =
^(NSURL *newURL, NSError *error) {
if (error) {
NSLog( @"Error writing image with metadata to Photo Library: %@", error );
} else {
NSLog( @"Wrote image with metadata to Photo Library %@", newURL.absoluteString);
}
};
if ([library videoAtPathIsCompatibleWithSavedPhotosAlbum:srcURL])
{
[library writeVideoAtPathToSavedPhotosAlbum:srcURL
completionBlock:videoWriteCompletionBlock];
}
}
Zoul 的上述回答很好地概述了您将要做什么。我们广泛地评论了这段代码，以便您可以看到它是如何使用工作代码完成的。
我借鉴了 Zoul 的主要思想，并结合了 AVAssetWriterInputPixelBufferAdaptor 方法，并以此开始了一些小框架。
随时检查并改进它！CEMovieMaker
这是在 iOS 8 上测试的 Swift 2.x 版本。它结合了来自 @Scott Raposa 和 @Praxiteles 的答案以及来自 @acj 为另一个问题提供的代码。@acj 的代码在这里：https ://gist.github.com/acj/6ae90aa1ebb8cad6b47b 。@TimBull 也提供了代码。
像@Scott Raposa 一样，我什至从未听说CVPixelBufferPoolCreatePixelBuffer过其他几个功能，更不用说了解如何使用它们了。
您在下面看到的内容主要是通过反复试验和阅读 Apple 文档拼凑而成的。请谨慎使用，如有错误请提出建议。
用法：
import UIKit
import AVFoundation
import Photos
writeImagesAsMovie(yourImages, videoPath: yourPath, videoSize: yourSize, videoFPS: 30)
代码：
func writeImagesAsMovie(allImages: [UIImage], videoPath: String, videoSize: CGSize, videoFPS: Int32) {
// Create AVAssetWriter to write video
guard let assetWriter = createAssetWriter(videoPath, size: videoSize) else {
print("Error converting images to video: AVAssetWriter not created")
return
}
// If here, AVAssetWriter exists so create AVAssetWriterInputPixelBufferAdaptor
let writerInput = assetWriter.inputs.filter{ $0.mediaType == AVMediaTypeVideo }.first!
let sourceBufferAttributes : [String : AnyObject] = [
kCVPixelBufferPixelFormatTypeKey as String : Int(kCVPixelFormatType_32ARGB),
kCVPixelBufferWidthKey as String : videoSize.width,
kCVPixelBufferHeightKey as String : videoSize.height,
]
let pixelBufferAdaptor = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: writerInput, sourcePixelBufferAttributes: sourceBufferAttributes)
// Start writing session
assetWriter.startWriting()
assetWriter.startSessionAtSourceTime(kCMTimeZero)
if (pixelBufferAdaptor.pixelBufferPool == nil) {
print("Error converting images to video: pixelBufferPool nil after starting session")
return
}
// -- Create queue for <requestMediaDataWhenReadyOnQueue>
let mediaQueue = dispatch_queue_create("mediaInputQueue", nil)
// -- Set video parameters
let frameDuration = CMTimeMake(1, videoFPS)
var frameCount = 0
// -- Add images to video
let numImages = allImages.count
writerInput.requestMediaDataWhenReadyOnQueue(mediaQueue, usingBlock: { () -> Void in
// Append unadded images to video but only while input ready
while (writerInput.readyForMoreMediaData && frameCount < numImages) {
let lastFrameTime = CMTimeMake(Int64(frameCount), videoFPS)
let presentationTime = frameCount == 0 ? lastFrameTime : CMTimeAdd(lastFrameTime, frameDuration)
if !self.appendPixelBufferForImageAtURL(allImages[frameCount], pixelBufferAdaptor: pixelBufferAdaptor, presentationTime: presentationTime) {
print("Error converting images to video: AVAssetWriterInputPixelBufferAdapter failed to append pixel buffer")
return
}
frameCount += 1
}
// No more images to add? End video.
if (frameCount >= numImages) {
writerInput.markAsFinished()
assetWriter.finishWritingWithCompletionHandler {
if (assetWriter.error != nil) {
print("Error converting images to video: \(assetWriter.error)")
} else {
self.saveVideoToLibrary(NSURL(fileURLWithPath: videoPath))
print("Converted images to movie @ \(videoPath)")
}
}
}
})
}
func createAssetWriter(path: String, size: CGSize) -> AVAssetWriter? {
// Convert <path> to NSURL object
let pathURL = NSURL(fileURLWithPath: path)
// Return new asset writer or nil
do {
// Create asset writer
let newWriter = try AVAssetWriter(URL: pathURL, fileType: AVFileTypeMPEG4)
// Define settings for video input
let videoSettings: [String : AnyObject] = [
AVVideoCodecKey : AVVideoCodecH264,
AVVideoWidthKey : size.width,
AVVideoHeightKey : size.height,
]
// Add video input to writer
let assetWriterVideoInput = AVAssetWriterInput(mediaType: AVMediaTypeVideo, outputSettings: videoSettings)
newWriter.addInput(assetWriterVideoInput)
// Return writer
print("Created asset writer for \(size.width)x\(size.height) video")
return newWriter
} catch {
print("Error creating asset writer: \(error)")
return nil
}
}
func appendPixelBufferForImageAtURL(image: UIImage, pixelBufferAdaptor: AVAssetWriterInputPixelBufferAdaptor, presentationTime: CMTime) -> Bool {
var appendSucceeded = false
autoreleasepool {
if let pixelBufferPool = pixelBufferAdaptor.pixelBufferPool {
let pixelBufferPointer = UnsafeMutablePointer<CVPixelBuffer?>.alloc(1)
let status: CVReturn = CVPixelBufferPoolCreatePixelBuffer(
kCFAllocatorDefault,
pixelBufferPool,
pixelBufferPointer
)
if let pixelBuffer = pixelBufferPointer.memory where status == 0 {
fillPixelBufferFromImage(image, pixelBuffer: pixelBuffer)
appendSucceeded = pixelBufferAdaptor.appendPixelBuffer(pixelBuffer, withPresentationTime: presentationTime)
pixelBufferPointer.destroy()
} else {
NSLog("Error: Failed to allocate pixel buffer from pool")
}
pixelBufferPointer.dealloc(1)
}
}
return appendSucceeded
}
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)
}
func saveVideoToLibrary(videoURL: NSURL) {
PHPhotoLibrary.requestAuthorization { status in
// Return if unauthorized
guard status == .Authorized else {
print("Error saving video: unauthorized access")
return
}
// If here, save video to library
PHPhotoLibrary.sharedPhotoLibrary().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideoAtFileURL(videoURL)
}) { success, error in
if !success {
print("Error saving video: \(error)")
}
}
}
}
刚刚翻译了@Scott Raposa 对 swift3 的回答（改动很小）：
import AVFoundation
import UIKit
import Photos
struct RenderSettings {
var size : CGSize = .zero
var fps: Int32 = 6 // frames per second
var avCodecKey = AVVideoCodecH264
var videoFilename = "render"
var videoFilenameExt = "mp4"
var outputURL: URL {
// Use the CachesDirectory so the rendered video file sticks around as long as we need it to.
// Using the CachesDirectory ensures the file won't be included in a backup of the app.
let fileManager = FileManager.default
if let tmpDirURL = try? fileManager.url(for: .cachesDirectory, in: .userDomainMask, appropriateFor: nil, create: true) {
return tmpDirURL.appendingPathComponent(videoFilename).appendingPathExtension(videoFilenameExt)
}
fatalError("URLForDirectory() failed")
}
}
class ImageAnimator {
// Apple suggests a timescale of 600 because it's a multiple of standard video rates 24, 25, 30, 60 fps etc.
static let kTimescale: Int32 = 600
let settings: RenderSettings
let videoWriter: VideoWriter
var images: [UIImage]!
var frameNum = 0
class func saveToLibrary(videoURL: URL) {
PHPhotoLibrary.requestAuthorization { status in
guard status == .authorized else { return }
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: videoURL)
}) { success, error in
if !success {
print("Could not save video to photo library:", error)
}
}
}
}
class func removeFileAtURL(fileURL: URL) {
do {
try FileManager.default.removeItem(atPath: fileURL.path)
}
catch _ as NSError {
// Assume file doesn't exist.
}
}
init(renderSettings: RenderSettings) {
settings = renderSettings
videoWriter = VideoWriter(renderSettings: settings)
// images = loadImages()
}
func render(completion: (()->Void)?) {
// The VideoWriter will fail if a file exists at the URL, so clear it out first.
ImageAnimator.removeFileAtURL(fileURL: settings.outputURL)
videoWriter.start()
videoWriter.render(appendPixelBuffers: appendPixelBuffers) {
ImageAnimator.saveToLibrary(videoURL: self.settings.outputURL)
completion?()
}
}
// // Replace this logic with your own.
// func loadImages() -> [UIImage] {
// var images = [UIImage]()
// for index in 1...10 {
// let filename = "\(index).jpg"
// images.append(UIImage(named: filename)!)
// }
// return images
// }
// This is the callback function for VideoWriter.render()
func appendPixelBuffers(writer: VideoWriter) -> Bool {
let frameDuration = CMTimeMake(Int64(ImageAnimator.kTimescale / settings.fps), ImageAnimator.kTimescale)
while !images.isEmpty {
if writer.isReadyForData == false {
// Inform writer we have more buffers to write.
return false
}
let image = images.removeFirst()
let presentationTime = CMTimeMultiply(frameDuration, Int32(frameNum))
let success = videoWriter.addImage(image: image, withPresentationTime: presentationTime)
if success == false {
fatalError("addImage() failed")
}
frameNum += 1
}
// Inform writer all buffers have been written.
return true
}
}
class VideoWriter {
let renderSettings: RenderSettings
var videoWriter: AVAssetWriter!
var videoWriterInput: AVAssetWriterInput!
var pixelBufferAdaptor: AVAssetWriterInputPixelBufferAdaptor!
var isReadyForData: Bool {
return videoWriterInput?.isReadyForMoreMediaData ?? false
}
class func pixelBufferFromImage(image: UIImage, pixelBufferPool: CVPixelBufferPool, size: CGSize) -> CVPixelBuffer {
var pixelBufferOut: CVPixelBuffer?
let status = CVPixelBufferPoolCreatePixelBuffer(kCFAllocatorDefault, pixelBufferPool, &pixelBufferOut)
if status != kCVReturnSuccess {
fatalError("CVPixelBufferPoolCreatePixelBuffer() failed")
}
let pixelBuffer = pixelBufferOut!
CVPixelBufferLockBaseAddress(pixelBuffer, CVPixelBufferLockFlags(rawValue: 0))
let data = CVPixelBufferGetBaseAddress(pixelBuffer)
let rgbColorSpace = CGColorSpaceCreateDeviceRGB()
let context = CGContext(data: data, width: Int(size.width), height: Int(size.height),
bitsPerComponent: 8, bytesPerRow: CVPixelBufferGetBytesPerRow(pixelBuffer), space: rgbColorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedFirst.rawValue)
context!.clear(CGRect(x:0,y: 0,width: size.width,height: size.height))
let horizontalRatio = size.width / image.size.width
let verticalRatio = size.height / image.size.height
//aspectRatio = max(horizontalRatio, verticalRatio) // ScaleAspectFill
let aspectRatio = min(horizontalRatio, verticalRatio) // ScaleAspectFit
let newSize = CGSize(width: image.size.width * aspectRatio, height: image.size.height * aspectRatio)
let x = newSize.width < size.width ? (size.width - newSize.width) / 2 : 0
let y = newSize.height < size.height ? (size.height - newSize.height) / 2 : 0
context?.draw(image.cgImage!, in: CGRect(x:x,y: y, width: newSize.width, height: newSize.height))
CVPixelBufferUnlockBaseAddress(pixelBuffer, CVPixelBufferLockFlags(rawValue: 0))
return pixelBuffer
}
init(renderSettings: RenderSettings) {
self.renderSettings = renderSettings
}
func start() {
let avOutputSettings: [String: Any] = [
AVVideoCodecKey: renderSettings.avCodecKey,
AVVideoWidthKey: NSNumber(value: Float(renderSettings.size.width)),
AVVideoHeightKey: NSNumber(value: Float(renderSettings.size.height))
]
func createPixelBufferAdaptor() {
let sourcePixelBufferAttributesDictionary = [
kCVPixelBufferPixelFormatTypeKey as String: NSNumber(value: kCVPixelFormatType_32ARGB),
kCVPixelBufferWidthKey as String: NSNumber(value: Float(renderSettings.size.width)),
kCVPixelBufferHeightKey as String: NSNumber(value: Float(renderSettings.size.height))
]
pixelBufferAdaptor = AVAssetWriterInputPixelBufferAdaptor(assetWriterInput: videoWriterInput,
sourcePixelBufferAttributes: sourcePixelBufferAttributesDictionary)
}
func createAssetWriter(outputURL: URL) -> AVAssetWriter {
guard let assetWriter = try? AVAssetWriter(outputURL: outputURL, fileType: AVFileTypeMPEG4) else {
fatalError("AVAssetWriter() failed")
}
guard assetWriter.canApply(outputSettings: avOutputSettings, forMediaType: AVMediaTypeVideo) else {
fatalError("canApplyOutputSettings() failed")
}
return assetWriter
}
videoWriter = createAssetWriter(outputURL: renderSettings.outputURL)
videoWriterInput = AVAssetWriterInput(mediaType: AVMediaTypeVideo, outputSettings: avOutputSettings)
if videoWriter.canAdd(videoWriterInput) {
videoWriter.add(videoWriterInput)
}
else {
fatalError("canAddInput() returned false")
}
// The pixel buffer adaptor must be created before we start writing.
createPixelBufferAdaptor()
if videoWriter.startWriting() == false {
fatalError("startWriting() failed")
}
videoWriter.startSession(atSourceTime: kCMTimeZero)
precondition(pixelBufferAdaptor.pixelBufferPool != nil, "nil pixelBufferPool")
}
func render(appendPixelBuffers: ((VideoWriter)->Bool)?, completion: (()->Void)?) {
precondition(videoWriter != nil, "Call start() to initialze the writer")
let queue = DispatchQueue(label: "mediaInputQueue")
videoWriterInput.requestMediaDataWhenReady(on: queue) {
let isFinished = appendPixelBuffers?(self) ?? false
if isFinished {
self.videoWriterInput.markAsFinished()
self.videoWriter.finishWriting() {
DispatchQueue.main.async {
completion?()
}
}
}
else {
// Fall through. The closure will be called again when the writer is ready.
}
}
}
func addImage(image: UIImage, withPresentationTime presentationTime: CMTime) -> Bool {
precondition(pixelBufferAdaptor != nil, "Call start() to initialze the writer")
let pixelBuffer = VideoWriter.pixelBufferFromImage(image: image, pixelBufferPool: pixelBufferAdaptor.pixelBufferPool!, size: renderSettings.size)
return pixelBufferAdaptor.append(pixelBuffer, withPresentationTime: presentationTime)
}
}
这是swift3版本如何将图像数组转换为视频
import Foundation
import AVFoundation
import UIKit
typealias CXEMovieMakerCompletion = (URL) -> Void
typealias CXEMovieMakerUIImageExtractor = (AnyObject) -> UIImage?
public class ImagesToVideoUtils: NSObject {
static let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
static let tempPath = paths[0] + "/exprotvideo.mp4"
static let fileURL = URL(fileURLWithPath: tempPath)
// static let tempPath = NSTemporaryDirectory() + "/exprotvideo.mp4"
// static let fileURL = URL(fileURLWithPath: tempPath)
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: AVVideoCodecJPEG, //AVVideoCodecH264,
AVVideoWidthKey: width,
AVVideoHeightKey: height]
return videoSettings
}
public init(videoSettings: [String: Any]) {
super.init()
if(FileManager.default.fileExists(atPath: ImagesToVideoUtils.tempPath)){
guard (try? FileManager.default.removeItem(atPath: ImagesToVideoUtils.tempPath)) != nil else {
print("remove path failed")
return
}
}
self.assetWriter = try! AVAssetWriter(url: ImagesToVideoUtils.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(1, 5)
}
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()
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!(ImagesToVideoUtils.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
}
}
我将它与屏幕捕获一起使用，基本上创建屏幕捕获视频，这是完整的故事/完整示例。
对于那些在 2020 年仍在进行旅程的人来说，他们的电影会因为宽度不是 16 像素而失真
改变
CGContextRef context = CGBitmapContextCreate(pxdata,
width, height,
8, 4 * width,
rgbColorSpace,
kCGImageAlphaNoneSkipFirst);
至
CGContextRef context = CGBitmapContextCreate(pxdata,
width, height,
8, CVPixelBufferGetBytesPerRow(pxbuffer),
rgbColorSpace,
kCGImageAlphaNoneSkipFirst);
归功于 AVAssetWriter 的 @bluedays输出（写入视频的 UIImages）失真
好吧，这在纯 Objective-C 中实现有点困难......如果您正在为越狱设备开发，一个好主意是在您的应用程序内部使用命令行工具 ffmpeg。使用以下命令从图像创建电影非常容易：
ffmpeg -r 10 -b 1800 -i %03d.jpg test1800.mp4
请注意，图像必须按顺序命名，并且必须放在同一目录中。有关更多信息，请查看： http ://electron.mit.edu/~gsteele/ffmpeg/