2013/4/15 Vittorio Giovara <[email protected]>

> On Mon, Apr 15, 2013 at 12:42 PM, Luca Barbato <[email protected]> wrote:
>
> > On 04/11/2013 04:56 PM, Yusuke Nakamura wrote:
> > > 2013/4/9 Luca Barbato <[email protected]>
> > >
> > >> On 09/04/13 10:16, Yusuke Nakamura wrote:
> > >>> Attached patches support setting field order information for H.264,
> > VC-1
> > >>> and MPEG-2 video stream by parsing.
> > >>
> > >> They look ok, the h264 one might be reformatted a little since chained
> > >> ternaries aren't that nice to follow.
> > >>
> > >> lu
> > >> _______________________________________________
> > >> libav-devel mailing list
> > >> [email protected]
> > >> https://lists.libav.org/mailman/listinfo/libav-devel
> > >>
> > >
> > >
> > > I replaced chained ternaries with if-else.
> > >
> >
> > I like the idea, who is against it?
> >
> > lu
> >
>
> Unless I'm missing something and if my understanding of the spec is
> correct, the SEI message used here to update field_order is originally
> intended only as a hint for the display. The "correct" way to understand if
> frame has been coded interlaced or progressive is by looking at
> frame_mbs_only_flag and field_pic_flag.
>
> Then again somewhere in the spec it should be written that the SEI must be
> initialized to the same value of frame_mbs_only_flag but I wouldn't rely on
> an optional SEI message to get the field order information.
>
> Best,
> Vittorio
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>

I don't care about progressive or interlaced.
I want to use field order information for pulldown to get frames correctly
and automatically by frame number on AVI-based editors.
Without pulldown, people is bothered with AV asynch on AVI-base editor
timeline.

As far as I understand, frame_mbs_only_flag == 1 guarantees that frames are
progressive, while frame_mbs_only_flag == 0 doesn't guarantee that a frame
is coded as progressive or interlaced.
And, if CpbDpbDelaysPresentFlag is equal to 1 or pic_struct_present_flag is
equal to 1, Picture timing SEI is not optional and it shall be present in
every access unit.
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