在我的项目中，我必须添加一个书页翻转动画，并且在这本书的右侧页面中将播放一个视频。一旦第一个视频完成，页面将变成书页，第二个视频将在下一个右侧页面上播放，依此类推。现在我必须将所有这些东西保存为可以下载的视频，这样当下载的视频从画廊播放时，它看起来就像我在我的应用程序中播放的一样。现在我正在录制设备的屏幕并将其保存在服务器中以供下载。除了视频播放器，其他一切都很好。在我正在录制的视频中，所有视频正在播放的部分（在书的右侧页面上）没有被录制。我正在使用下面的代码来记录屏幕。如果你们中的任何人有其他想法来做同样的事情，请与我分享，或者如果需要更改我的代码，请提出建议。谢谢是提前。
// ASScreenRecorder.h
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
typedef void (^VideoCompletionBlock)(void);
@protocol ASScreenRecorderDelegate;
@interface ASScreenRecorder : NSObject
@property (nonatomic, readonly) BOOL isRecording;
@property (nonatomic, weak) id <ASScreenRecorderDelegate> delegate;
// if saveURL is nil, video will be saved into camera roll
// this property can not be changed whilst recording is in progress
@property (strong, nonatomic) NSURL *videoURL;
+ (instancetype)sharedInstance;
- (BOOL)startRecording;
- (void)stopRecordingWithCompletion:(VideoCompletionBlock)completionBlock;
@end
// If your view contains an AVCaptureVideoPreviewLayer or an openGL view
// you'll need to write that data into the CGContextRef yourself.
// In the viewcontroller responsible for the AVCaptureVideoPreviewLayer / openGL view
// set yourself as the delegate for ASScreenRecorder.
// [ASScreenRecorder sharedInstance].delegate = self
// Then implement 'writeBackgroundFrameInContext:(CGContextRef*)contextRef'
// use 'CGContextDrawImage' to draw your view into the provided CGContextRef
@protocol ASScreenRecorderDelegate <NSObject>
- (void)writeBackgroundFrameInContext:(CGContextRef*)contextRef;
@end
// ASScreenRecorder.m
// ScreenRecorder
//
// Created by Alan Skipp on 23/04/2014.
// Copyright (c) 2014 Alan Skipp. All rights reserved.
//
#import "ASScreenRecorder.h"
#import <AVFoundation/AVFoundation.h>
#import <QuartzCore/QuartzCore.h>
#import <AssetsLibrary/AssetsLibrary.h>
@interface ASScreenRecorder()
@property (strong, nonatomic) AVAssetWriter *videoWriter;
@property (strong, nonatomic) AVAssetWriterInput *videoWriterInput;
@property (strong, nonatomic) AVAssetWriterInputPixelBufferAdaptor *avAdaptor;
@property (strong, nonatomic) CADisplayLink *displayLink;
@property (strong, nonatomic) NSDictionary *outputBufferPoolAuxAttributes;
@property (nonatomic) CFTimeInterval firstTimeStamp;
@property (nonatomic) BOOL isRecording;
@end
@implementation ASScreenRecorder
{
dispatch_queue_t _render_queue;
dispatch_queue_t _append_pixelBuffer_queue;
dispatch_semaphore_t _frameRenderingSemaphore;
dispatch_semaphore_t _pixelAppendSemaphore;
CGSize _viewSize;
CGFloat _scale;
CGColorSpaceRef _rgbColorSpace;
CVPixelBufferPoolRef _outputBufferPool;
}
#pragma mark - initializers
+ (instancetype)sharedInstance {
static dispatch_once_t once;
static ASScreenRecorder *sharedInstance;
dispatch_once(&once, ^{
sharedInstance = [[self alloc] init];
});
return sharedInstance;
}
- (instancetype)init
{
self = [super init];
if (self) {
_viewSize = [UIApplication sharedApplication].delegate.window.bounds.size;
_scale = [UIScreen mainScreen].scale;
// record half size resolution for retina iPads
if ((UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) && _scale > 1) {
_scale = 1.0;
}
_isRecording = NO;
_append_pixelBuffer_queue = dispatch_queue_create("ASScreenRecorder.append_queue", DISPATCH_QUEUE_SERIAL);
_render_queue = dispatch_queue_create("ASScreenRecorder.render_queue", DISPATCH_QUEUE_SERIAL);
dispatch_set_target_queue(_render_queue, dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_HIGH, 0));
_frameRenderingSemaphore = dispatch_semaphore_create(1);
_pixelAppendSemaphore = dispatch_semaphore_create(1);
}
return self;
}
#pragma mark - public
- (void)setVideoURL:(NSURL *)videoURL
{
NSAssert(!_isRecording, @"videoURL can not be changed whilst recording is in progress");
_videoURL = videoURL;
}
- (BOOL)startRecording
{
if (!_isRecording) {
[self setUpWriter];
_isRecording = (_videoWriter.status == AVAssetWriterStatusWriting);
_displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(writeVideoFrame)];
[_displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
}
return _isRecording;
}
- (void)stopRecordingWithCompletion:(VideoCompletionBlock)completionBlock;
{
if (_isRecording) {
_isRecording = NO;
[_displayLink removeFromRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
[self completeRecordingSession:completionBlock];
}
}
#pragma mark - private
-(void)setUpWriter
{
_rgbColorSpace = CGColorSpaceCreateDeviceRGB();
NSDictionary *bufferAttributes = @{(id)kCVPixelBufferPixelFormatTypeKey : @(kCVPixelFormatType_32BGRA),
(id)kCVPixelBufferCGBitmapContextCompatibilityKey : @YES,
(id)kCVPixelBufferWidthKey : @(_viewSize.width * _scale),
(id)kCVPixelBufferHeightKey : @(_viewSize.height * _scale),
(id)kCVPixelBufferBytesPerRowAlignmentKey : @(_viewSize.width * _scale * 4)
};
_outputBufferPool = NULL;
CVPixelBufferPoolCreate(NULL, NULL, (__bridge CFDictionaryRef)(bufferAttributes), &_outputBufferPool);
NSError* error = nil;
_videoWriter = [[AVAssetWriter alloc] initWithURL:self.videoURL ?: [self tempFileURL]
fileType:AVFileTypeQuickTimeMovie
error:&error];
NSParameterAssert(_videoWriter);
NSInteger pixelNumber = _viewSize.width * _viewSize.height * _scale;
NSDictionary* videoCompression = @{AVVideoAverageBitRateKey: @(pixelNumber * 11.4)};
NSDictionary* videoSettings = @{AVVideoCodecKey: AVVideoCodecH264,
AVVideoWidthKey: [NSNumber numberWithInt:_viewSize.width*_scale],
AVVideoHeightKey: [NSNumber numberWithInt:_viewSize.height*_scale],
AVVideoCompressionPropertiesKey: videoCompression};
_videoWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];
NSParameterAssert(_videoWriterInput);
_videoWriterInput.expectsMediaDataInRealTime = YES;
_videoWriterInput.transform = [self videoTransformForDeviceOrientation];
_avAdaptor = [AVAssetWriterInputPixelBufferAdaptor assetWriterInputPixelBufferAdaptorWithAssetWriterInput:_videoWriterInput sourcePixelBufferAttributes:nil];
[_videoWriter addInput:_videoWriterInput];
[_videoWriter startWriting];
[_videoWriter startSessionAtSourceTime:CMTimeMake(0, 1000)];
}
- (CGAffineTransform)videoTransformForDeviceOrientation
{
CGAffineTransform videoTransform;
switch ([UIDevice currentDevice].orientation) {
case UIDeviceOrientationLandscapeLeft:
videoTransform = CGAffineTransformMakeRotation(-M_PI_2);
break;
case UIDeviceOrientationLandscapeRight:
videoTransform = CGAffineTransformMakeRotation(M_PI_2);
break;
case UIDeviceOrientationPortraitUpsideDown:
videoTransform = CGAffineTransformMakeRotation(M_PI);
break;
default:
videoTransform = CGAffineTransformIdentity;
}
return videoTransform;
}
- (NSURL*)tempFileURL
{
NSString *outputPath = [NSHomeDirectory() stringByAppendingPathComponent:@"tmp/screenCapture.mp4"];
[self removeTempFilePath:outputPath];
return [NSURL fileURLWithPath:outputPath];
}
- (void)removeTempFilePath:(NSString*)filePath
{
NSFileManager* fileManager = [NSFileManager defaultManager];
if ([fileManager fileExistsAtPath:filePath]) {
NSError* error;
if ([fileManager removeItemAtPath:filePath error:&error] == NO) {
NSLog(@"Could not delete old recording:%@", [error localizedDescription]);
}
}
}
- (void)completeRecordingSession:(VideoCompletionBlock)completionBlock;
{
dispatch_async(_render_queue, ^{
dispatch_sync(_append_pixelBuffer_queue, ^{
[_videoWriterInput markAsFinished];
[_videoWriter finishWritingWithCompletionHandler:^{
void (^completion)(void) = ^() {
[self cleanup];
dispatch_async(dispatch_get_main_queue(), ^{
if (completionBlock) completionBlock();
});
};
if (self.videoURL) {
completion();
} else {
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library writeVideoAtPathToSavedPhotosAlbum:_videoWriter.outputURL completionBlock:^(NSURL *assetURL, NSError *error) {
if (error) {
NSLog(@"Error copying video to camera roll:%@", [error localizedDescription]);
} else {
[self removeTempFilePath:_videoWriter.outputURL.path];
completion();
}
}];
}
}];
});
});
}
- (void)cleanup
{
self.avAdaptor = nil;
self.videoWriterInput = nil;
self.videoWriter = nil;
self.firstTimeStamp = 0;
self.outputBufferPoolAuxAttributes = nil;
CGColorSpaceRelease(_rgbColorSpace);
CVPixelBufferPoolRelease(_outputBufferPool);
}
- (void)writeVideoFrame
{
// throttle the number of frames to prevent meltdown
// technique gleaned from Brad Larson's answer here: http://stackoverflow.com/a/5956119
if (dispatch_semaphore_wait(_frameRenderingSemaphore, DISPATCH_TIME_NOW) != 0) {
return;
}
dispatch_async(_render_queue, ^{
if (![_videoWriterInput isReadyForMoreMediaData]) return;
if (!self.firstTimeStamp) {
self.firstTimeStamp = _displayLink.timestamp;
}
CFTimeInterval elapsed = (_displayLink.timestamp - self.firstTimeStamp);
CMTime time = CMTimeMakeWithSeconds(elapsed, 1000);
CVPixelBufferRef pixelBuffer = NULL;
CGContextRef bitmapContext = [self createPixelBufferAndBitmapContext:&pixelBuffer];
if (self.delegate) {
[self.delegate writeBackgroundFrameInContext:&bitmapContext];
}
// draw each window into the context (other windows include UIKeyboard, UIAlert)
// FIX: UIKeyboard is currently only rendered correctly in portrait orientation
dispatch_sync(dispatch_get_main_queue(), ^{
UIGraphicsPushContext(bitmapContext); {
for (UIWindow *window in [[UIApplication sharedApplication] windows]) {
[window drawViewHierarchyInRect:CGRectMake(0, 0, _viewSize.width, _viewSize.height) afterScreenUpdates:NO];
}
} UIGraphicsPopContext();
});
// append pixelBuffer on a async dispatch_queue, the next frame is rendered whilst this one appends
// must not overwhelm the queue with pixelBuffers, therefore:
// check if _append_pixelBuffer_queue is ready
// if it’s not ready, release pixelBuffer and bitmapContext
if (dispatch_semaphore_wait(_pixelAppendSemaphore, DISPATCH_TIME_NOW) == 0) {
dispatch_async(_append_pixelBuffer_queue, ^{
BOOL success = [_avAdaptor appendPixelBuffer:pixelBuffer withPresentationTime:time];
if (!success) {
NSLog(@"Warning: Unable to write buffer to video");
}
CGContextRelease(bitmapContext);
CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
CVPixelBufferRelease(pixelBuffer);
dispatch_semaphore_signal(_pixelAppendSemaphore);
});
} else {
CGContextRelease(bitmapContext);
CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);
CVPixelBufferRelease(pixelBuffer);
}
dispatch_semaphore_signal(_frameRenderingSemaphore);
});
}
- (CGContextRef)createPixelBufferAndBitmapContext:(CVPixelBufferRef *)pixelBuffer
{
CVPixelBufferPoolCreatePixelBuffer(NULL, _outputBufferPool, pixelBuffer);
CVPixelBufferLockBaseAddress(*pixelBuffer, 0);
CGContextRef bitmapContext = NULL;
bitmapContext = CGBitmapContextCreate(CVPixelBufferGetBaseAddress(*pixelBuffer),
CVPixelBufferGetWidth(*pixelBuffer),
CVPixelBufferGetHeight(*pixelBuffer),
8, CVPixelBufferGetBytesPerRow(*pixelBuffer), _rgbColorSpace,
kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst
);
CGContextScaleCTM(bitmapContext, _scale, _scale);
CGAffineTransform flipVertical = CGAffineTransformMake(1, 0, 0, -1, 0, _viewSize.height);
CGContextConcatCTM(bitmapContext, flipVertical);
return bitmapContext;
}
@end