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    Correct Premiere CS5 / AE CS5 footage interpretation?
    #1
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    Hello,

    I have a HMC150 and primarily shoot 1080p 30p and import and edit in premiere cs5. For months now I have just left the footage interpretation to default, and all has gone mostly well, but recently after deciding to understand what is actually going on behind the scenes I have become a bit confused. The footage default interprets to Upper Field first rather than progressive, which I have read contradicting posts as to the reasoning why. Some say, including Barry Green, that it is shot in a 60i data stream and therefore Premiere is rightfully interpreting it as Upper field first. Another post said this is a bug in premiere and you should force interpret each file to None - progressive in field order.

    1) Which of these is the correct interpretation for the 1080 30p footage, and if it is indeed Upper field first, can someone explain what exactly having 30p in a 60i data stream means? Does it make the footage interlaced and what is the difference in viewing between a 30p in 60i stream and a raw 30p stream. Will the video look interlaced or need to be de-interlaced?

    My second question / issue is that after effects, using roto brush, will claim there is a frame-rate mismatch and that the composition should be set to 59.94 frames per second in order to roto correctly and match the source footage. Here again I am confused as I was shooting in 30p.

    Basically I am looking to know what is the "Right" way to interpret this footage and composition/sequence in PP and AE, and what are the side effects of it being in a 60i data stream if it is indeed supposed to run in a 59.94 composition as AE states. Or is this all a bug and I need to force everything to 30p settings?

    I am about to just shoot 24p from now on lol...

    Thanks,


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    #2
    Senior Member
    Join Date
    Sep 2010
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    765
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    The right way to interpret the footage is to drag the clip to the "new sequence" button and it will create a sequence based on the settings of the clip.

    The HMC150 (and all other cameras, I *think*) captures 30p over 60i. I don't know the technical intricacies behind it but that's what it does. Your footage is still progressive but played back in a 60i stream. It has to do with the fact that there is no NTSC 30p broadcast standard, but there is a 60i standard -- 60i can also carry a progressive image.


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    #3
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    That's interesting thanks for the reply. When I typically create my own sequence I chose AVCHD 1080P square pixel 29.97fps, with the - Editing mode: AVCHD 1080p square pixel - but when I drag it to new sequence button it creates it as - Editing mode AVCHD 1080i square pixel. I cannot tell or see any differences between the two, but I am curious if any experts know if the sequence being 1080i or 1080p would matter for shooting 1080 30p on the HMC?

    Also when I talked about interpreting footage I meant by right clicking - modify - interpret footage and if there was a need to force change from default (upper field first) to (progressive).

    I can't see how any of this explains after effects insisting the source footage is 59.94 fps when I use the Roto Brush.


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