What's difference between mpeg4 and mpeg 2 yuv 4:2:0 pixel formats?

[keesbor98]

There are "PrPixelFormat_YUV_420_MPEG2_FRAME_PICTURE_PLANAR_8u_601" and "PrPixelFormat_YUV_420_MPEG4_FRAME_PICTURE_PLANAR_8u_601". They difference only in component ordering or something else?

[Rallymax-forum]

technically the difference is where in the 2x2 block the chroma is sampled.

In practice there is no difference.