带有mp4格式的IOS UIImagePicker

Question

是否可以保存视频并将其添加到自定义 ALAsset，以 mp4 格式从 UIImagePicker 捕获？或者我必须将它保存在 .mov 中并通过 AVAssetExportSession 进行压缩？

Answer 1

是的，您可以使用 压缩视频AVAssetExportSession。您可以在此处指定压缩视频的视频类型、质量和输出 URL。

参见以下方法：

- (void) saveVideoToLocal:(NSURL *)videoURL {

    @try {
        NSArray *documentsDirectory = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *docPath = [documentsDirectory objectAtIndex:0];

        NSString *videoName = [NSString stringWithFormat:@"sampleVideo.mp4"];
        NSString *videoPath = [docPath stringByAppendingPathComponent:videoName];

        NSURL *outputURL = [NSURL fileURLWithPath:videoPath];

        NSLog(@"Loading video");

        [self convertVideoToLowQuailtyWithInputURL:videoURL outputURL:outputURL handler:^(AVAssetExportSession *exportSession) {

             if (exportSession.status == AVAssetExportSessionStatusCompleted) {
                 NSLog(@"Compression is done");
             }
             [self performSelectorOnMainThread:@selector(doneCompressing) withObject:nil waitUntilDone:YES];
         }];
    }
    @catch (NSException *exception) {
        NSLog(@"Exception :%@",exception.description);
        [self performSelectorOnMainThread:@selector(doneCompressing) withObject:nil waitUntilDone:YES];
    }
}


//---------------------------------------------------------------

- (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:AVAssetExportPresetPassthrough];
    exportSession.outputURL = outputURL;
    exportSession.outputFileType = AVFileTypeMPEG4;
    [exportSession exportAsynchronouslyWithCompletionHandler:^(void) {
        handler(exportSession);
    }];
}

这里我将压缩视频保存到应用程序的文档目录中。您可以在下面的示例代码中检查其详细工作原理：

示例演示：