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

问题描述

我在录制视频之前调用了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;

在录制视频和通过电子邮件分享等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.

如果我将视频质量用作高品质，那么录制的视频已变得庞大。例如，如果我以高质量录制视频30秒，则录制的视频大约为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;

我如何编程在共享之前压缩高质量录制的视频，就像Apple如何处理内置视频一样-in录像机？

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

请指导我解决此问题。

谢谢！

更新：

这是我最近的尝试，但仍然没有成功：我想要压缩拍摄的录制视频来到didFinishPickingMediaWithInfo并存储在相同的相册实际视频路径本身，而不是其他任何地方。我测试相同的视频被压缩到非常小的尺寸，当我从照片库中选择时，但是从相机拍摄的同一视频来自didFinishPickingMediaWithInfo并未压缩，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

如果你想压缩用于远程共享的视频并保留iPhone上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.

同时阅读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\n");
         }
         else
         {
             printf("error\n");

         }
     }];

}

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