视频截图获取视频某一帧做图片

╰半橙微兮° 2022-03-16 07:54 363阅读 0赞

本地存储的视频文件，通过某些方法获取该视频的首帧图片，或是某个时间的图片，或是该视图不同时间段的多张图片。

获取视频第一帧的图片，示例代码如下：

+ (UIImage *)videoThumbnailWithFilePath:(NSString *)filePath
    {
        if (filePath == nil || filePath.length <= 0) {
            return nil;
        }
        
        NSURL *url = [NSURL fileURLWithPath:filePath];
        AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:url options:nil];
        AVAssetImageGenerator *assetGen = [[AVAssetImageGenerator alloc] initWithAsset:asset];
        
        assetGen.appliesPreferredTrackTransform = YES;
        CMTime time = CMTimeMakeWithSeconds(0.0, 600);
        NSError *error = nil;
        CMTime actualTime;
        CGImageRef image = [assetGen copyCGImageAtTime:time actualTime:&actualTime error:&error];
        UIImage *videoImage = [[UIImage alloc] initWithCGImage:image];
        CGImageRelease(image);
        return videoImage;
    }

> 需要导入头文件’\#import <AVFoundation/AVFoundation.h>’

获取视频某个时间的图片，示例代码如下：

+ (UIImage *)videoThumbnailWithFilePath:(NSString *)filePath atTime:(NSTimeInterval)time
    {
        if (filePath == nil || filePath.length <= 0) {
            return nil;
        }
        
        NSURL *url = [NSURL fileURLWithPath:filePath];
        MPMoviePlayerController *moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:url];
        moviePlayer.shouldAutoplay = NO;
        UIImage *videoImage = [moviePlayer thumbnailImageAtTime:time timeOption:MPMovieTimeOptionNearestKeyFrame];
        return videoImage;
    }

> 需要导入头文件’\#import <MediaPlayer/MediaPlayer.h>’

获取视频不同时间的多张图片，示例代码如下：

+ (void)videoThumbnailWithFilePath:(NSString *)filePath count:(NSInteger)count complete:(void(^)(BOOL success, NSArray *images))complete
    {
        if (filePath == nil || filePath.length <= 0) {
            if (complete) {
                complete(NO, nil);
            }
        } else {
            __block BOOL isSuccess = NO;
            __block NSMutableArray *images = [[NSMutableArray alloc] init];
            count = (count == 0 ? 1 : count);
            
            NSURL *url = [NSURL fileURLWithPath:filePath];
            AVAsset *asset = [AVAsset assetWithURL:url];
            [asset loadValuesAsynchronouslyForKeys:@[@"duration"] completionHandler:^{
                AVAssetImageGenerator *generator = [AVAssetImageGenerator assetImageGeneratorWithAsset:asset];
                // 如果是CGSizeMake(480,136)，则获取到的图片是{240, 136}。与实际大小成比例
                // generator.maximumSize = CGSizeMake(480,136);
                // 这个属性保证我们获取的图片的方向是正确的。比如有的视频需要旋转手机方向才是视频的正确方向。
                generator.appliesPreferredTrackTransform = YES;
                /**因为有误差，所以需要设置以下两个属性。如果不设置误差有点大，设置了之后相差非常非常的小**/
                generator.requestedTimeToleranceAfter = kCMTimeZero;
                generator.requestedTimeToleranceBefore = kCMTimeZero;
                Float64 seconds = CMTimeGetSeconds(asset.duration);
                NSMutableArray *array = [NSMutableArray array];
                for (int i = 0; i < count; i++) {
                    // 想要获取图片的时间位置
                    CMTime time = CMTimeMakeWithSeconds(i * (seconds / 10.0), 1);
                    [array addObject:[NSValue valueWithCMTime:time]];
                }
                __block int i = 0;
                [generator generateCGImagesAsynchronouslyForTimes:array completionHandler:^(CMTime requestedTime, CGImageRef  _Nullable imageRef, CMTime actualTime, AVAssetImageGeneratorResult result, NSError * _Nullable error) {
                    
                    i++;
                    if (result == AVAssetImageGeneratorSucceeded) {
                        isSuccess = YES;
                        UIImage *image = [UIImage imageWithCGImage:imageRef];
                        [images addObject:image];
                    } else {
                        isSuccess = NO;
                    }
                    
                    if (i == count) {
                        dispatch_async(dispatch_get_main_queue(), ^{
                            if (complete) {
                                complete(isSuccess, images);
                            }
                        });
                    }
                }];
            }];
        }
    }

> 需要导入头文件’\#import <AVFoundation/AVFoundation.h>’