Incorrect pixel format

[vyeevani]

kCMVideoCodecType_422YpCbCr8 corresponds to uy1vy2. However, the current alias is to yuyv which results in incorrect conversion. There's a separate type that's needed to model the uy1vy2 format. I can put up a PR that addresses this if needed.

[vyeevani]

links to the descriptions:
https://developer.apple.com/documentation/coremedia/kcmvideocodectype_422ypcbcr8
https://developer.apple.com/documentation/coremedia/kcmpixelformat_422ypcbcr8_yuvs