Hi -

> From: Selva Nair <[EMAIL PROTECTED]>
> But why do you care about top_field first when the source is progressive? 

        I don't care which order the fields come in - could have been the DV
        standard's bottom first and I'd have been just as happy.

> If you use 24000:1001 and pulldown instead of 30000:1001, the encoder will
> keep switching between top_field_first = true/false to generate the
> pulldown sequence.

        Now it's my turn to ask why would I want to do a pulldown when I have
        ~30fps interlaced with is what I wanted all along?

> By progressive if you mean progressive_frame flagged as true, again, 
> use 24000:1001 and pulldown you will have it.

        But that's precisely what I do not want - or at least I'm fairly 
        sure I do not need it.   I was concerned that progressive IN would
        yield progressive OUT and that won't work with DVDs.

> But if you want a progressive sequence the dvd preset wont allow it
> as DVDs are for interlaced displays by design. I think mpeg2enc will

        Exactly - so since the encoder will take the generated frames and
        split each into two fields as I want why bother with converted film
        rates and the pulldown?

> generate progressive sequences with a generic mpeg2 preset plus -I 0.

        I wonder if that'll work - have to try it.   Of course it'd be for
        a small clip since 1280x768 is going to be very slow encoding (~3x
        slower than encoding 720x480).

> You have the full 444 chroma info at the ppm stage so isn't it  best 
> to subsample it directly to 420_mpeg2 from the ppm? Otherwise you go 
> through 444 -> 420_jpeg -> 420_mpeg2 -- looks more lossy to me.

        Hmmm, possible but I have a feeling that the jpeg->mpeg2 conversion's
        "loss" is so small you'd need Golden Eyeballs to notice it ;)  Certainly
        it'd be a lot less of a loss than the 444 -> xxx conversion.

        Now to do what I probably should have done before posting this - get
        a cup of coffee :)

        Cheers,
        Steven Schultz


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