Ecco l'ultimo codice funzionante su iOS8 in Objective-C.
Abbiamo dovuto apportare una serie di modifiche alla risposta di @ Zoul sopra per farlo funzionare sull'ultima versione di Xcode e iOS8. Ecco il nostro codice di lavoro completo che prende una matrice di UIImages, li trasforma in un file .mov, lo salva in una directory temporanea, quindi lo sposta sul rullino fotografico. Abbiamo assemblato il codice da più post diversi per farlo funzionare. Abbiamo evidenziato le trappole che dovevamo risolvere per far funzionare il codice nei nostri commenti.
(1) Crea una raccolta di 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)];
}
Questo è il metodo principale che crea AssetWriter e aggiunge immagini per la scrittura.
(2) Collegare 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) Inizia una sessione di scrittura (NOTA: il metodo continua dall'alto)
//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) Termina la sessione (Nota: il metodo continua dall'alto)
//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) Converti le tue UIImages in CVPixelBufferRef
Questo metodo ti fornirà un riferimento al buffer pixel CV che è necessario per AssetWriter. Questo è ottenuto da un CGImageRef che ottieni dal tuo UIImage (sopra).
- (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) Sposta il video sul rullino della fotocamera
Poiché AVAssetWriter non è in grado di scrivere direttamente sul rullino della fotocamera, questo sposta il video da "tmp / temp.mov" (o qualsiasi nome di file che hai chiamato sopra) al rullino della fotocamera.
- (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 risposta di Zoul qui sopra fornisce una bella descrizione di ciò che farai. Abbiamo ampiamente commentato questo codice in modo da poter vedere come è stato fatto utilizzando il codice di lavoro.