ios - AVAssetWriterInput 当前不支持 AVVideoScalingModeFit - IOS 错误

Question

我正在尝试使用 AVAssetWriterInput 裁剪我在应用程序的截屏视频中阅读的视频。这是我当前的配置。

NSDictionary *videoCleanApertureSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                            [NSNumber numberWithInt:320], AVVideoCleanApertureWidthKey,
                                            [NSNumber numberWithInt:480], AVVideoCleanApertureHeightKey,
                                            [NSNumber numberWithInt:10], AVVideoCleanApertureHorizontalOffsetKey,
                                            [NSNumber numberWithInt:10], AVVideoCleanApertureVerticalOffsetKey,
                                            nil];


NSDictionary *videoAspectRatioSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                          [NSNumber numberWithInt:3], AVVideoPixelAspectRatioHorizontalSpacingKey,
                                          [NSNumber numberWithInt:3],AVVideoPixelAspectRatioVerticalSpacingKey,
                                          nil];

NSDictionary *codecSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                               [NSNumber numberWithInt:960000], AVVideoAverageBitRateKey,
                               [NSNumber numberWithInt:1],AVVideoMaxKeyFrameIntervalKey,
                               videoCleanApertureSettings, AVVideoCleanApertureKey,
                               videoAspectRatioSettings, AVVideoPixelAspectRatioKey,
                               AVVideoProfileLevelH264BaselineAutoLevel, AVVideoProfileLevelKey,
                               nil];

NSDictionary *videoSettings = @{AVVideoCodecKey:AVVideoCodecH264,
                                AVVideoCompressionPropertiesKey:codecSettings,
                                AVVideoScalingModeKey:AVVideoScalingModeResizeAspectFill,
                                AVVideoWidthKey:[NSNumber numberWithInt:320],
                                AVVideoHeightKey:[NSNumber numberWithInt:480]};

_videoWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo outputSettings:videoSettings];

我收到以下错误:“AVAssetWriterInput 当前不支持 AVVideoScalingModeFit”

对于使用此库的任何人来说，这是一个常见错误，但我找不到真正的解决方案。我只是看到人们说:“我最终弄明白了”，却没有解释。问题肯定与这一行有关:“AVVideoScalingModeKey:AVVideoScalingModeResizeAspectFill”，它告诉 AVAssetWriter 裁剪视频并保持纵横比。有人知道解决这个问题的方法吗？

Answer 1

本身没有“解决方案”。它根本不受支持。您需要使用 Core Image 或 VTPixelTransferSession 或任何适合您的管道的内容自行缩放视频帧。