Alternate scan flag for interlaced MPEG4 ASP

[adkumar]

I guess Alternate scan flag is set at VOP level for interlace pictures.And Alternate scan flag is useful with Field DCT but
I geuss Field/frame DCT dicision is taken at MB level.

Normally in what condition "Alternate scan flag " is set to 1 ?

If the dicision is taken at sequence level.wat is the use of it?


Thanks and Regards
Kumar

[adkumar]

please give me some pointers,where i can get info about it?........

[adkumar]

Divx and XviD encoder are truning the "Alternate scan flag" 0

is there any typical encoder making it 1?