Why/when to use codec friendly sizing in the VDub resize filter?

[brassplyer]

Using the resize filter in Virtualdub, when would you use the option for codec friendly sizing - multiples of 2, 4, 8, 16?

Thanks

[Cornucopia]

Any codec that uses block level DCT requires it (which integer depends on the block size). This includes: DV/DVCPRO/DVCPRO50/DVCPRO100, MPEG 1, MPEG2, MPEG4/DivX/Xvid/Wmv/Vc1, H.261, H.263 H.264, H.265.
It is probably a good idea to use it with full frame wavelet codecs (DNxHD, Cineform). In fact, it's probably a good idea to use it all of the time.

Scott

[brassplyer]

Any codec that uses block level DCT requires it (which integer depends on the block size). This includes: DV/DVCPRO/DVCPRO50/DVCPRO100, MPEG 1, MPEG2, MPEG4/DivX/Xvid/Wmv/Vc1, H.261, H.263 H.264, H.265.
It is probably a good idea to use it with full frame wavelet codecs (DNxHD, Cineform). In fact, it's probably a good idea to use it all of the time.

Scott

How would one find out which option you should use with what codec?