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Crop comp to ROI doesn't work

Aug 17, 2012 3:11 AM

I'm new to After Effects and I'm using AE6.


I'm working on a video clip.


After drawing a Region of Interest I selected Crop Comp to Region of Interest in the Composition drop down menu.  Nothing happens!  The original bounding box of the comp stays the same and when I render with Crop>use region of interest checked off it crops only the width but not the height.


Any suggestions?

  • Currently Being Moderated
    Aug 17, 2012 4:13 AM   in reply to raylaur

    Screenshots perhaps? More info on you system and comp settings?



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  • Currently Being Moderated
    Aug 17, 2012 5:14 AM   in reply to raylaur

    The first question I have after seeing your screenshots is what are you going to do with this cropped comp. This new comp size isn't standard to anything and won't work for most delivery codecs. Even encoding for the web or playback in a browser or powerpoint using H.264 won't work because MPEG codecs have very specific frame size requirements that you must consider.


    The second thing that is probably confusing you is the bounding box. The bounding box always shows the boundary of the clip and it has nothing to do with the size of the composition. You can hide it using the View Options or by deselecting Show Layer Controls.


    The composition settings clearly show a comp with a non standard frame size that is smaller than HD. It looks like Crop to ROI worked just fine. The size of the composition changed. The only problem I see is that this comp won't render to any standard delivery format without problems.


    I will occasionally use crop to region of interest if I'm pre-rendering a shot for use in another composition using an appropriate codec. I will also occasionally crop a pre-comp to make it easier to deal with in a complex project. The feature isn't useful for much else.

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    Aug 17, 2012 7:20 AM   in reply to raylaur

    As far as I can tell, there's nothing wrong. As Rick said, the layer bounding box still remains the same after the crop. Only when you pre-compose and use the nested comp will the bounding box change and, as per your own observation, it will do the same when applying a mask. Your render issues may be/ are format specific. Compressed formats always are tied to specific aspect ratios or minimum values in eitehr dimension and those dimensions will always be even multiples of 2/4/8/16 and so on due to how their math works. Plus they will always quantize to the next valid resolution within their spec. So from where I sit everything is as it should be/ will have to be.



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    Aug 17, 2012 11:41 AM   in reply to raylaur

    If you're rendering to FLV then your output is being stretched to the nearest legal frame size. If you're nesting this cropped comp in another comp to render a final product to FLV for final output there is also no need to crop the composition.


    >>>  I'm rendering to FLV and it works fine in my presentation.

    You may think it's fine but it could be better.


    If you are rendering this cropped comp to FLV and combining the result in flash then your comp is being stretched to the nearest legal frame size. The resulting render will be distorted and a little softer than it should be.


    If you feel you must reduce the dimensions keyed video then nest your keyed comp in a legal sized composition. FLV is just h.264 in a different wrapper.


    At the very least, make sure that your final composition has even numbers for horizontal and vertical dimensions. It will render in less time and it will retain more of the original detail.

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