如何使用AVAssetWriter將視頻裁剪為方形iOS

Question

我正在使用AVAssetWriter來錄制視頻，我希望能夠將視頻裁剪成一個偏離頂部的正方形。 這是我的代碼 -

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


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



NSDictionary *codecSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                               [NSNumber numberWithInteger:bitsPerSecond], AVVideoAverageBitRateKey,
                               @1,AVVideoMaxKeyFrameIntervalKey,
                               videoCleanApertureSettings, AVVideoCleanApertureKey,
                               //AVVideoScalingModeFit,AVVideoScalingModeKey,
                               videoAspectRatioSettings, AVVideoPixelAspectRatioKey,
                               nil];

NSDictionary *videoCompressionSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                               AVVideoCodecH264, AVVideoCodecKey,
                               codecSettings,AVVideoCompressionPropertiesKey,
                               @320, AVVideoWidthKey,
                               @320, AVVideoHeightKey,
                               nil];

每當我取消注釋AVVideoScalingModeKey時，我的assetWriter都會給出一個關於無法應用videoCompressionSettings的錯誤。 我嘗試過如何使用AVAssetWriter制作縮小尺寸的視頻？ 但它仍然不適合我。

Answer 1

我將AVVideoScalingModeFit,AVVideoScalingModeKey添加到我的videoCompressionSettings以使其工作。