AVAssetWriter无法使用AVVideoProfileLevelKey编码视频 [英] AVAssetWriter failing to encode video with AVVideoProfileLevelKey

问题描述

有人可以帮我解决这个问题吗? 我可以使用具有以下输出设置的AVAssetWriter对视频进行编码.

Can anyone help me out with this problem? I am able to encode a video using AVAssetWriter with following output settings.

NSDictionary *videoCompressionSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                          AVVideoCodecH264, AVVideoCodecKey,
                                          [NSNumber numberWithInteger:dimensions.width], AVVideoWidthKey,
                                          [NSNumber numberWithInteger:dimensions.height], AVVideoHeightKey,
                                          [NSDictionary dictionaryWithObjectsAndKeys:
                                           [NSNumber numberWithInteger:bitsPerSecond], AVVideoAverageBitRateKey,
                                           [NSNumber numberWithInteger:30],AVVideoMaxKeyFrameIntervalKey,
                                           nil], AVVideoCompressionPropertiesKey,   
                                          nil];

但是，当我尝试通过指定配置文件进行编码时，请说AVVideoProfileLevelH264Baseline30输出设置，这看起来像

However when i try to encode by specifying a profile say AVVideoProfileLevelH264Baseline30 output settings after this will look like

NSDictionary *videoCompressionSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                          AVVideoCodecH264, AVVideoCodecKey,
                                          [NSNumber numberWithInteger:dimensions.width], AVVideoWidthKey,
                                          [NSNumber numberWithInteger:dimensions.height], AVVideoHeightKey,
                                          [NSDictionary dictionaryWithObjectsAndKeys:
                                           [NSNumber numberWithInteger:bitsPerSecond], AVVideoAverageBitRateKey,
                                           [NSNumber numberWithInteger:30],AVVideoMaxKeyFrameIntervalKey,
                                           AVVideoProfileLevelH264Baseline30,AVVideoProfileLevelKey,
                                           nil], AVVideoCompressionPropertiesKey,   
                                          nil];

使用这些设置，我的视频录制失败.

My video recording fails with these settings.

那么我的问题在哪里? 我已经像这样

So where is my problem here ? I have initialized Asset writer like this

_assetWriter = [[AVAssetWriter alloc] initWithURL:_movieURL fileType:AVFileTypeMPEG4 error:&error];

推荐答案

我也遇到了这种失败.对我来说，问题仅存在于OS X 10.7(Lion)上，它根本不支持AVVideoProfileLevelKey ...您仍然可以在H.264中进行编码，但是只需要省略该参数，OS便可以处理选择配置文件的问题.使用.如果您在OS X 10.8/10.9或iOS 4或更高版本上看到此操作失败，则说明您还有其他问题.

I've had this fail too. For me, the problem was only on OS X 10.7 (Lion), which simply does not support AVVideoProfileLevelKey... You can still encode in H.264, but just need to omit that parameter, and the OS will handle choosing a profile to use. If you're seeing this fail on OS X 10.8/10.9, or iOS 4 or later, then there's something else going wrong for you.

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