[M4IF Technotes] question about top_field_first!

[Xue Xuhong]

Dear Experts,
We know ASP Profile includes Interlace Tool. In syntax, top_field_first is a
parameter about interlace, whose meaning is defined as below(reference to
w3056):
"This is a 1-bit flag which when set to "1" indicates that the top field
(i.e., the field containing the top line) of reconstructed VOP is the first
field to be displayed (output by the decoding process).  When
top_field_first is set to "0" it indicates that the bottom field of the
reconstructed VOP is the first field to be displayed "
As it describes, when reconstructed VOP is to be displayed, top_field_first
is an useful information to control which field should be first displayed.
We wonder that whether  it is necessary to display the two fields of the
reconstructed VOP in consecutive different time? That is, when
top_field_first =1, then the top field should be displayed first , and it
will hold for 1/2 Tframe(Tframe is the frame period ), then the bottom field
should be displayed, and it will hold the  remained  1/2 Tframe.
Is our understanding right?
Thanks for your help!
Regards,
Xue Xuhong
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