ios 视频选择封面功能

//两个代理
@interface ViewController ()<UIImagePickerControllerDelegate, UINavigationControllerDelegate>

@property (weak, nonatomic) IBOutlet UIImageView *coverImageView;

@end

//代理方法
//打开相册
- (void)openImagePickerController:(UIImagePickerControllerSourceType)type
{
if (![UIImagePickerController isSourceTypeAvailable:type]) return;

UIImagePickerController *ipc = [[UIImagePickerController alloc] init];

//视频最大时间
ipc.videoMaximumDuration = 30;
ipc.view.backgroundColor = [UIColor whiteColor];
ipc.sourceType = type;
ipc.delegate = self;
//只打开视频
ipc.mediaTypes = @[(NSString *)kUTTypeMovie];
//视频上传质量
ipc.videoQuality = UIImagePickerControllerQualityTypeHigh;
[self presentViewController:ipc animated:YES completion:nil];
}

#pragma mark - UIImagePickerControllerDelegate
/**
* 从UIImagePickerController选择完图片后就调用（拍照完毕或者选择相册图片完毕）
*/

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {

CZHWeakSelf(self);

NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];

if ([mediaType isEqualToString:(NSString *)kUTTypeMovie]) {
//如果是视频
NSURL *url = info[UIImagePickerControllerMediaURL];
//计算相册视频时长
NSDictionary *videoDic = [CZHTool getLocalVideoSizeAndTimeWithSourcePath:url.absoluteString];
int videoTime = [[videoDic valueForKey:@"duration"] intValue];
//视频限制的长度
NSUInteger limitTime = 30;
if (videoTime > limitTime) {
[picker dismissViewControllerAnimated:YES completion:nil];
return;
}
//把系统相册mov格式转换成mp4格式
[CZHTool convertMovTypeIntoMp4TypeWithSourceUrl:url convertSuccess:^(NSURL *path) {
CZHStrongSelf(self);
[picker dismissViewControllerAnimated:YES completion:nil];
//选择封面控制器
CZHChooseCoverController *chooseCover = [[CZHChooseCoverController alloc] init];
//本地路径
chooseCover.videoPath = path;
//选择封面的block，把封面image回调
chooseCover.coverImageBlock = ^(UIImage *coverImage) {
self.coverImageView.image = coverImage;

//上传视频操作
//[self changeWithUploadSource:path];
//上传封面操作
//[self uploadCoverWithImage:coverImage];
};
[self presentViewController:chooseCover animated:YES completion:nil];
}];
}
}

// 取消图片选择调用此方法
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
// dismiss UIImagePickerController
[self dismissViewControllerAnimated:YES completion:nil];
}

//截取几张图片放在底部用作展示，我是用collectionview做展示
AVURLAsset * asset = [AVURLAsset assetWithURL:self.videoPath];
CMTime  time = [asset duration];
self.timeValue = time.value;
self.timeScale = time.timescale;
if (time.value < 1) {
[self dismissViewControllerAnimated:YES completion:nil];
return;
}

NSDictionary *opts = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:NO] forKey:AVURLAssetPreferPreciseDurationAndTimingKey];
AVURLAsset *urlAsset = [AVURLAsset URLAssetWithURL:self.videoPath options:opts];
AVAssetImageGenerator *generator = [AVAssetImageGenerator assetImageGeneratorWithAsset:urlAsset];
generator.appliesPreferredTrackTransform = YES;
//总帧数/展示的总数量
long long baseCount = time.value / PHOTP_COUNT;
//取出PHOTP_COUNT张图片,存放到数组，用于collectionview
for (NSInteger i = 0 ; i < PHOTP_COUNT; i++) {

NSError *error = nil;
//每隔baseCount帧取一帧存起来,一共PHOTP_COUNT张
CGImageRef img = [generator copyCGImageAtTime:CMTimeMake(i * baseCount, time.timescale) actualTime:NULL error:&error];
{
UIImage *image = [UIImage imageWithCGImage:img];

[self.photoArrays addObject:image];
}
}

//把存的存的几张图片用collectionview展示出来
CGRect collectionViewF = CGRectMake(0,  CZH_ScaleHeight(461), ScreenWidth, CZH_ScaleHeight(62.5));
UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:collectionViewF collectionViewLayout:layout];
collectionView.dataSource = self;
collectionView.backgroundColor = [UIColor clearColor];
[collectionView registerClass:[CZHChooseCoverCell class] forCellWithReuseIdentifier:ID];
[self.view addSubview:collectionView];
self.collectionView  = collectionView;

//在collectionview上面覆盖一个slider用于滑动选择图片
UIImage *selected = [UIImage imageNamed:@"slider_select"];
UIImage *deselected = [UIImage imageNamed:@"slider_deselect"];

UISlider *slider = [[UISlider alloc] init];
slider.frame = CGRectMake(0,  CZH_ScaleHeight(461), ScreenWidth, CZH_ScaleHeight(62.5));

[slider setThumbImage:deselected forState:UIControlStateNormal];
[slider setThumbImage:selected forState:UIControlStateHighlighted];
//透明的图片
UIImage *image = [CZHTool imageWithColor:[UIColor clearColor] size:CGSizeMake(1, 1)];

[slider setMinimumTrackImage:image forState:UIControlStateNormal];
[slider setMaximumTrackImage:image forState:UIControlStateNormal];

slider.maximumValue = self.timeValue;
slider.minimumValue = 0;
[slider addTarget:self action:@selector(valueChange:) forControlEvents:UIControlEventValueChanged];
[self.view addSubview:slider];

//默认选取第一帧展示
[self chooseWithTime:0];

//滑动slider的操作
- (void)valueChange:(UISlider *)sender {

int timeValue = sender.value;

[self chooseWithTime:timeValue];
}

- (void)chooseWithTime:(CMTimeValue)time {

NSDictionary *opts = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:NO] forKey:AVURLAssetPreferPreciseDurationAndTimingKey];
AVURLAsset *urlAsset = [AVURLAsset URLAssetWithURL:self.videoPath options:opts];
AVAssetImageGenerator *generator = [AVAssetImageGenerator assetImageGeneratorWithAsset:urlAsset];
generator.appliesPreferredTrackTransform = YES;
//    generator.maximumSize = CGSizeMake(ScreenWidth, ScreenHeight);

NSError *error = nil;
CGImageRef img = [generator copyCGImageAtTime:CMTimeMake(time, self.timeScale) actualTime:NULL error:&error];
{
UIImage *image = [UIImage imageWithCGImage:img];

self.imageView.image = image;
}
}

//点击返回按钮和完成按钮的操作
- (void)buttonClick:(UIButton *)sender {
if (sender.tag == CZHChooseCoverControllerButtonTypeBack) {
[self dismissViewControllerAnimated:YES completion:nil];
} else if (sender.tag == CZHChooseCoverControllerButtonTypeComplete) {
//封面图片回调
if (_coverImageBlock) {
_coverImageBlock(self.imageView.image);
}
[self dismissViewControllerAnimated:YES completion:nil];
}
}

NSMutableArray *videoArray = [NSMutableArray array];
//工程中类型是MP4的文件数组
NSArray *movs = [[NSBundle mainBundle] pathsForResourcesOfType:@"mp4" inDirectory:nil];
[videoArray addObjectsFromArray:movs];
for (id item in videoArray) {
//循环保存到相册
if (UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(item)) {
UISaveVideoAtPathToSavedPhotosAlbum(item, self, nil, NULL);
}
}