iOS

系统原生视频解码压缩处理方式

Posted by 阿唯不知道 on December 15, 2017
需要导入:#import <AVFoundation/AVFoundation.h>
使用到的变量:
@property (nonatomic, strong) NSString * videoPath;//视频压缩处理后的路径
@property (nonatomic, strong) NSString * qualityPreset; //预设视频压缩画质
代码调用方式:
[self alertVideoHandleModel];
核心代码展示:
- (void)alertVideoHandleModel {
    UIAlertController *actionSheet = [UIAlertController alertControllerWithTitle:@"视频选择" message:@"您可在相册中选择视频,也可以直接录制视频" preferredStyle:UIAlertControllerStyleActionSheet];
    UIAlertAction *chooseVideoAction = [UIAlertAction actionWithTitle:@"" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        [self chooseVideo];
    }];
    UIAlertAction *recordVideoAction = [UIAlertAction actionWithTitle:@"" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        [self startRecordVideo];
    }];
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
    [actionSheet addAction:chooseVideoAction];
    [actionSheet addAction:recordVideoAction];
    [actionSheet addAction:cancelAction];
    [self presentViewController:actionSheet animated:YES completion:nil];
}

#pragma mark *** Video Handling -------------- Start -------------- ***

// 选择本地视频
- (void)chooseVideo {
    UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    imagePicker.mediaTypes = @[(NSString *)kUTTypeMovie];
    [self presentViewController:imagePicker animated:YES completion:nil];
    imagePicker.delegate = self;
}

// 录制视频
- (void)startRecordVideo {
    UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
    imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
    imagePicker.mediaTypes = @[(NSString *)kUTTypeMovie];
    [self presentViewController:imagePicker animated:YES completion:nil];
    // 最长拍摄 300秒(5分钟)
    imagePicker.videoMaximumDuration = 5.0 * 60.0f;
    imagePicker.delegate = self;
}

// 获取文件的大小,返回的是单位是MB。
- (CGFloat)getFileSize:(NSString *)path {
    NSFileManager *fileManager = [NSFileManager defaultManager];
    float filesize = -1.0;
    if ([fileManager fileExistsAtPath:path]) {
        // 获取文件的属性
        NSDictionary *fileDic = [fileManager attributesOfItemAtPath:path error:nil];
        unsigned long long size = [[fileDic objectForKey:NSFileSize] longLongValue];
        filesize = 1.0*size/1024/1024;
    } else {
        NSLog(@"没有找到相关文件");
    }
    return filesize;
}

// 获取视频文件的时长。
- (CGFloat)getVideoLength:(NSURL *)URL {
    AVURLAsset *avUrl = [AVURLAsset assetWithURL:URL];
    CMTime time = [avUrl duration];
    int second = ceil(time.value / time.timescale);
    return second;
}

// 获取视频第一帧图片 
- (UIImage *)getFirstFrameWithVideoURL:(NSURL *)URL {
    NSDictionary *opts = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:NO] forKey:AVURLAssetPreferPreciseDurationAndTimingKey];
    AVURLAsset *urlAsset = [AVURLAsset URLAssetWithURL:URL options:opts];
    AVAssetImageGenerator *generator = [AVAssetImageGenerator assetImageGeneratorWithAsset:urlAsset];
    generator.appliesPreferredTrackTransform = YES;
    generator.maximumSize = CGSizeMake(400, 200);
    NSError *error = nil;
    CGImageRef img = [generator copyCGImageAtTime:CMTimeMake(0, 10) actualTime:NULL error:&error];
    if (!error) {
        return [UIImage imageWithCGImage:img];
    }
    return nil;
}

// 删除导出后的视频
- (void)removeWithVideoPath:(NSString *)path {
    // 删除文件
    BOOL isDelete = [[NSFileManager defaultManager] removeItemAtPath:path error:nil];
    if (!isDelete) {
        NSLog(@"视频删除失败");
    }
}

#pragma mark - <UIImagePickerControllerDelegate>
// 完成视频录制,并压缩后显示大小、时长
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    // 拿到视频地址
    NSURL *sourceURL = [info objectForKey:UIImagePickerControllerMediaURL];
    // 将视频第一帧图片赋值给按钮
    [self.addVedioBtn setImage:[self getFirstFrameWithVideoURL:sourceURL] forState:UIControlStateNormal];
    CGFloat videoSize = [self getFileSize:[sourceURL path]];
    NSLog(@"压缩处理之前的视频时长:%@",[NSString stringWithFormat:@"%f s", [self getVideoLength:sourceURL]]);
    NSLog(@"压缩处理之前的视频大小:%@", [NSString stringWithFormat:@"%.2f MB", videoSize]);
    // 预设压缩质量(最高画质)
    _qualityPreset = AVAssetExportPresetHighestQuality;
    // 如果视频大于 1000MB 则最低画质压缩
    if (videoSize > 1000) {
        _qualityPreset = AVAssetExportPresetLowQuality;
    } else if (videoSize > 20) {
        // 中等画质压缩
        _qualityPreset = AVAssetExportPresetMediumQuality;
    }
     // 配置输出的视频文件,保存在app自己的沙盒路径里,在上传后删除掉。
    NSURL *newVideoUrl;
    NSDateFormatter *formater = [[NSDateFormatter alloc] init];
    //用时间给文件全名,以免重复,在测试的时候其实可以判断文件是否存在若存在,则删除,重新生成文件即可
    [formater setDateFormat:@"yyyy-MM-dd-HH:mm:ss"];
    newVideoUrl = [NSURL fileURLWithPath:[NSHomeDirectory() stringByAppendingFormat:@"/Documents/output-%@.mp4", [formater stringFromDate:[NSDate date]]]] ;
    [picker dismissViewControllerAnimated:YES completion:nil];
    [self convertVideoQuailtyWithInputURL:sourceURL outputURL:newVideoUrl completeHandler:nil];
}

// 视频压缩转码处理
- (void)convertVideoQuailtyWithInputURL:(NSURL*)inputURL
                               outputURL:(NSURL*)outputURL
                         completeHandler:(void (^)(AVAssetExportSession*))handler {
    AVURLAsset *avAsset = [AVURLAsset URLAssetWithURL:inputURL options:nil];
    if (!_qualityPreset) {
        _qualityPreset = AVAssetExportPresetMediumQuality;
    }
    AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:avAsset presetName:_qualityPreset];
    exportSession.outputURL = outputURL;
    exportSession.outputFileType = AVFileTypeMPEG4;
    exportSession.shouldOptimizeForNetworkUse= YES;
    [exportSession exportAsynchronouslyWithCompletionHandler:^(void) {
         switch (exportSession.status) {
             case AVAssetExportSessionStatusCancelled:
                 NSLog(@"AVAssetExportSessionStatusCancelled");
                 break;
             case AVAssetExportSessionStatusUnknown:
                 NSLog(@"AVAssetExportSessionStatusUnknown");
                 break;
             case AVAssetExportSessionStatusWaiting:
                 NSLog(@"AVAssetExportSessionStatusWaiting");
                 break;
             case AVAssetExportSessionStatusExporting:
                 NSLog(@"AVAssetExportSessionStatusExporting");
                 break;
             case AVAssetExportSessionStatusCompleted:
                 NSLog(@"AVAssetExportSessionStatusCompleted");
                 CGFloat videoSize = [self getFileSize:[outputURL path]];
                 NSLog(@"压缩处理后的视频时长:%@",[NSString stringWithFormat:@"%f s", [self getVideoLength:outputURL]]);
                 NSLog(@"压缩处理后的视频大小:%@", [NSString stringWithFormat:@"%.2f MB", videoSize]);
                 // 导出完成后再赋值
                 _videoPath = [outputURL path];
                 break;
             case AVAssetExportSessionStatusFailed:
                 NSLog(@"AVAssetExportSessionStatusFailed");
                 break;
         }
     }];
}
#pragma mark *** Video Handling -------------- End -------------- ***