Comment exporter un tableau UIImage sous forme de film ?

Question

J'ai un sérieux problème : j'ai un NSArray avec plusieurs UIImage objets. Ce que je veux faire maintenant, c'est créer un film à partir de ces objets. UIImages . Mais je n'ai aucune idée de la manière de le faire.

J'espère que quelqu'un pourra m'aider ou m'envoyer un extrait de code qui fait quelque chose comme je le souhaite.

Editar: Pour référence future - Après avoir appliqué la solution, si la vidéo semble déformée, assurez-vous que la largeur des images/de la zone que vous capturez est un multiple de 16. Trouvé après de nombreuses heures de lutte ici :
Pourquoi mon film de UIImages est-il déformé ?

Voici la solution complète (assurez-vous simplement que la largeur est un multiple de 16)
http://codethink.no-ip.org/wordpress/archives/673

Answer 1

Jetez un coup d'œil à AVAssetWriter et le reste de la Cadre d'AVFoundation . Le rédacteur a une entrée de type AVAssetWriterInput qui, à son tour, possède une méthode appelée appendSampleBuffer : qui vous permet d'ajouter des images individuelles à un flux vidéo. Essentiellement, vous devrez :

1) Câblez l'écrivain :

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) Commencez une session :

[videoWriter startWriting];
[videoWriter startSessionAtSourceTime:…] //use kCMTimeZero if unsure

3) Rédigez quelques échantillons :

// 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) Terminez la session :

[writerInput markAsFinished];
[videoWriter endSessionAtSourceTime:…]; //optional can call finishWriting without specifying endTime
[videoWriter finishWriting]; //deprecated in ios6
/*
[videoWriter finishWritingWithCompletionHandler:...]; //ios 6.0+
*/

Il vous faudra encore remplir de nombreux espaces vides, mais je pense que la seule partie vraiment difficile qui reste est l'obtention d'un tampon de pixels à partir d'un fichier 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 est un CGSize décrivant votre taille de cadre cible et frameTransform est un CGAffineTransform qui vous permet de transformer les images lorsque vous les dessinez dans des cadres.

Answer 2

Mise à jour vers Swift 5

La semaine dernière, j'ai entrepris d'écrire le code iOS permettant de générer une vidéo à partir d'images. J'avais un peu d'expérience avec AVFoundation, mais je n'avais jamais entendu parler d'un CVPixelBuffer. J'ai trouvé les réponses sur cette page et aussi aquí . Il m'a fallu plusieurs jours pour tout disséquer et tout remettre en ordre dans Swift d'une manière qui ait un sens pour mon cerveau. Voici ce à quoi j'ai abouti.

NOTE : Si vous copiez/collez tout le code ci-dessous dans un seul fichier Swift, il devrait compiler. Vous aurez juste besoin de modifier loadImages() et le RenderSettings valeurs.

Partie 1 : Mise en place

Ici, je regroupe tous les paramètres liés à l'exportation en un seul RenderSettings struct.

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")
}

Partie 2 : L'ImageAnimator

El ImageAnimator connaît vos images et utilise la classe VideoWriter pour effectuer le rendu. L'idée est de garder le code du contenu vidéo séparé du code de bas niveau d'AVFoundation. J'ai également ajouté saveToLibrary() ici comme une fonction de classe qui est appelée à la fin de la chaîne pour enregistrer la vidéo dans la photothèque.

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
}

Partie 3 : Le VideoWriter

El VideoWriter fait tout le travail de AVFoundation. C'est surtout une enveloppe autour de AVAssetWriter y AVAssetWriterInput . Il contient aussi du code fantaisiste écrit par pas moi qui sait comment traduire une image en un 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)
}

Partie 4 : Réaliser le projet

Une fois que tout est en place, ce sont vos 3 lignes magiques :

let settings = RenderSettings()
let imageAnimator = ImageAnimator(renderSettings: settings)
imageAnimator.render() {
    print("yes")
}

Answer 3

Voici le dernier code fonctionnel sur iOS8 en Objective-C.

Nous avons dû apporter diverses modifications à la réponse de @Zoul ci-dessus pour qu'elle fonctionne avec la dernière version de Xcode et iOS8. Voici notre code complet qui prend un tableau de UIImages, les transforme en un fichier .mov, l'enregistre dans un répertoire temporaire, puis le déplace vers le rouleau de la caméra. Nous avons assemblé du code provenant de plusieurs articles différents pour obtenir ce résultat. Nous avons mis en évidence les pièges que nous avons dû résoudre pour que le code fonctionne dans nos commentaires.

(1) Créer une collection d'UIImages

[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)];
}

Il s'agit de la méthode principale qui crée votre AssetWriter et lui ajoute des images à écrire.

(2) Câbler un 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) Commencez une session d'écriture (REMARQUE : la méthode se poursuit à partir du point précédent)

    //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) Terminer la session (Note : la méthode continue à partir de ce qui précède)

                //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) Convertissez vos UIImages en CVPixelBufferRef
Cette méthode vous donnera une référence de tampon de pixel CV qui est nécessaire pour l'AssetWriter. Cette référence est obtenue à partir d'un CGImageRef que vous avez obtenu de votre UIImage (ci-dessus).

- (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) Déplacez votre vidéo vers le Camera Roll Comme l'AVAssetWriter ne peut pas écrire directement dans le rouleau de la caméra, cette opération déplace la vidéo de "tmp/temp.mov" (ou du nom de fichier que vous lui avez donné ci-dessus) vers le rouleau de la caméra.

- (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];
    }
}

La réponse de Zoul ci-dessus donne un bon aperçu de ce que vous allez faire. Nous avons abondamment commenté ce code afin que vous puissiez voir comment il a été fait en utilisant un code fonctionnel.

Answer 4

J'ai pris les idées principales de Zoul et j'ai incorporé la méthode AVAssetWriterInputPixelBufferAdaptor et j'en ai fait les prémices d'un petit framework.

N'hésitez pas à le vérifier et à l'améliorer ! CEMovieMaker

Answer 5

Voici une version de Swift 2.x testée sur iOS 8. Elle combine les réponses de @Scott Raposa et @Praxiteles ainsi que le code de @acj contribué pour une autre question. Le code de @acj est ici : https://gist.github.com/acj/6ae90aa1ebb8cad6b47b . @TimBull a également fourni du code.

Comme @Scott Raposa, je n'avais même jamais entendu parler de CVPixelBufferPoolCreatePixelBuffer et plusieurs autres fonctions, et encore moins compris comment les utiliser.

Ce que vous voyez ci-dessous a été bricolé principalement par essais et erreurs et en lisant les documents d'Apple. Veuillez l'utiliser avec prudence et nous faire part de vos suggestions en cas d'erreur.

Utilisation :

import UIKit
import AVFoundation
import Photos

writeImagesAsMovie(yourImages, videoPath: yourPath, videoSize: yourSize, videoFPS: 30)

Code :

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)")
            }
        }
    }
}