Static kVTSampleAttachmentQualityMetricsKey_ChromaRedMeanSquaredError 

pub unsafe static kVTSampleAttachmentQualityMetricsKey_ChromaRedMeanSquaredError: &'static CFString

Available on crate feature VTCompressionProperties only.

Key for mean squared error (MSE) of the encoded Chroma Red channel from the video encoder.

For single-view video, a CFNumber value is returned. For multi-view video, a CFArray value is returned, and each element (CFNumber) in the CFArray includes MSE for the corresponding view. The video encoder will attach this in kVTSampleAttachmentKey_QualityMetrics via the CMSampleBufferGetSampleAttachmentsArray interface before emitting the sample buffer.

See also Apple’s documentation