iPhone:以编程方式压缩录制的视频以共享? [英] iPhone:Programmatically compressing recorded video to share?

问题描述

我在录制视频之前调用相机视图时实现了叠加视图.

I have implemented an overlay view when calling camera view before recording the video.

pickerController.cameraOverlayView =myOverlay;

录制视频并通过电子邮件等方式共享后，视频录制并将视频保存到相册中.一切正常.

Video recording and saving the video into Album after recording the video and sharing via email etc. all works fine.

如果我使用视频质量为高质量"，那么录制的视频就会变得非常大.例如，如果我以高质量录制 30 秒的视频，录制的视频将变为大约 30 - 40 mb.

If i use video quality as "High quality", then the recorded video has become huge size. For example, if i record video for 30 seconds with high quality, recorded video has become around 30 - 40 mb.

pickerController.videoQuality = UIImagePickerControllerQualityTypeHigh;

我如何编程以在共享之前压缩高质量录制的视频，就像 Apple 使用内置视频录像机所做的那样?

How do i program to compress the high quality recorded video before sharing it, like how Apple does with built-in Video recorder?

请指导我解决这个问题.

Please guide me to resolve this.

谢谢！

更新:

这是我最近尝试的，但仍然没有成功:我想压缩来自 didFinishPickingMediaWithInfo 的录制视频，并将实际视频路径本身存储在同一个相册中，而不是其他任何地方.当我从照片库中选择时，我测试了相同的视频被压缩到非常小的尺寸，但是从相机拍摄并通过 didFinishPickingMediaWithInfo 获得的相同视频没有被压缩，尽管我使用了下面的 AVAssetExportSession 代码.

This is what i'm trying recently, but still no success: I want to compress the recorded video taken which comes to didFinishPickingMediaWithInfo and store in same photo album actual video path itself, not anywhere else. I tested the same video is compressed to very small size when i pick from photo library, but the same video taken from camera and came via didFinishPickingMediaWithInfo is not compressed, though i used the AVAssetExportSession code below.

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{

    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];


if ([mediaType isEqualToString:(NSString *)kUTTypeMovie])
{

    NSURL *videoURL = [info objectForKey:UIImagePickerControllerMediaURL];
    NSString *urlPath = [videoURL path];

    if ([[urlPath lastPathComponent] isEqualToString:@"capturedvideo.MOV"])
    {
        if (UIVideoAtPathIsCompatibleWithSavedPhotosAlbum (urlPath))
        {
            [self copyTempVideoToMediaLibrary :urlPath];


        }
        else
        {
            NSLog(@"Video Capture Error: Captured video cannot be saved...didFinishPickingMediaWithInfo()");                
        }
    }       
    else
    {
        NSLog(@"Processing soon to saved photos album...else loop of lastPathComponent..didFinishPickingMediaWithInfo()");
    }
}    
[self dismissModalViewControllerAnimated:YES];
}

- (void)copyTempVideoToMediaLibrary :(NSString *)videoURL {

        dispatch_queue_t mainQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

dispatch_async(mainQueue, ^{

    ALAssetsLibrary *library = [[[ALAssetsLibrary alloc] init] autorelease];

    ALAssetsLibraryWriteVideoCompletionBlock completionBlock = ^(NSURL *assetURL, NSError *error) {
        NSLog(@"Saved URL: %@", assetURL);
        NSLog(@"Error: %@", error);

        if (assetURL != nil) {

            AVURLAsset *theAsset = [AVURLAsset URLAssetWithURL:[NSURL URLWithString:videoURL] options:nil];

            NSArray *compatiblePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:theAsset];

            AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:theAsset presetName:AVAssetExportPresetLowQuality];

            [exportSession setOutputURL:[NSURL URLWithString:videoURL]];
            [exportSession setOutputFileType:AVFileTypeQuickTimeMovie];

            [exportSession exportAsynchronouslyWithCompletionHandler:^ {
                switch ([exportSession status]) {
                    case AVAssetExportSessionStatusFailed:
                        NSLog(@"Export session faied with error: %@", [exportSession error]);
                        break;
                    default:
                        //[self mediaIsReady];
                        break;
                }
            }];
        }
    };

    [library writeVideoAtPathToSavedPhotosAlbum:[NSURL URLWithString:videoURL] completionBlock:completionBlock];
});
}

推荐答案

如果您想压缩视频以进行远程共享并保持 iPhone 本地存储的原始质量，您应该查看 AVAssetExportSession 或 AVAssetWriter.

If you want to compress the video for remote sharing and keep the original quality for local storage on the iPhone, you should look into AVAssetExportSession or AVAssetWriter.

另请阅读 iOS 如何管理 资产.

Also read up on how iOS manages Assets.

- (void)convertVideoToLowQuailtyWithInputURL:(NSURL*)inputURL 
                                   outputURL:(NSURL*)outputURL 
                                     handler:(void (^)(AVAssetExportSession*))handler
{
    [[NSFileManager defaultManager] removeItemAtURL:outputURL error:nil];
    AVURLAsset *asset = [AVURLAsset URLAssetWithURL:inputURL options:nil];
    AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetLowQuality];
    exportSession.outputURL = outputURL;
    exportSession.outputFileType = AVFileTypeQuickTimeMovie;
    [exportSession exportAsynchronouslyWithCompletionHandler:^(void) 
    {
        handler(exportSession);
        [exportSession release];
    }];
}

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info

{   
    NSURL *videoURL = [info objectForKey:UIImagePickerControllerMediaURL];
    NSURL *outputURL = [NSURL fileURLWithPath:@"/Users/josh/Desktop/output.mov"];
    [self convertVideoToLowQuailtyWithInputURL:videoURL outputURL:outputURL handler:^(AVAssetExportSession *exportSession)
     {
         if (exportSession.status == AVAssetExportSessionStatusCompleted)
         {
             printf("completed
");
         }
         else
         {
             printf("error
");

         }
     }];

}

这篇关于iPhone:以编程方式压缩录制的视频以共享?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！