Zigzag scan type ????

[Haku]

When using bitrate viewer to see what field was first,i saw that next to scan type it said zigzag.

what is zigzag,as ive not had that b4 ,normally i get alternate.

[adam]

zigzag and alternate scan order are patterns used when sequencing DTC coefficients. Assuming you are not using any custom matrices, zigzag may produce higher quality with progressive sources and alternate may produce higher quality with interlaced sources.

Mpeg1 can only use zigzag scanning order since it doesnt support interlacing. For mpeg2 your encoder may or may not allow you to edit this parameter. CCE does, TMPGenc does not as far as I know.

[Haku]

The movie i have is Pal Interlaced ,top field first,so even though bitrate viewer says zigzig should i encode it to Alternate as like u said

" zigzag may produce higher quality with progressive sources and alternate may produce higher quality with interlaced sources. "

[adam]

If your source is interlaced then yes it would be better to use alternate scan, though honestly I doubt it will cause any noticable difference.