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  1. Member
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    Maybe I'm missing something but this seems like it should be easy...
    I'm trying to downsize some HD recordings from 720p 59.94fps to 480 29.97. Specifically, if it matters, Family Guy. The mpegs are pulled directly from my Comcast 6412 DVR via firewire (btw, the HD mpegs are 10000% nicer quality than the regular SD streams). Cropping 160 pixels from the L and R sides of the 1280x720 mpeg would give me a 4:3 picture. With MPEG Streamclip, how do I crop first BEFORE resizing? If I set it to export at 720x480, the crop always takes place after the downsizing. I actually tried a custom size of 960x480, cropped 120 pixels from each side, and came pretty close. Is there a better way?
    I'm open to using another tool, but I like the fact that MPEG Streamclip can crop, resize, and convert framerates all in one shot.
    Also, to export to an uncompressed format, what should I use? Apple None is what QuickTime uses for uncompressed video but it doesn't show up in the MPEG Streamclip export options.
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  2. So you want to crop 1280x720 to 960x720, then scale 960x720 to 720x480, right? (Hmm, shouldn't you scale to 656x480 IF you are using square pixels in all steps? Is HD square pixels?? Is the target rectangular pixels?).

    Anyway, there are some things to remember with MPEG Streamclip:

    If you choose a DV frame size as an output, the "Scale" option has no effect and the picture is always scaled to match the input resolution (this is why you must Zoom into the image to preserve the correct aspect ratio with DV output when doing a simple crop of DV material).

    http://www.sjoki.uta.fi/~shmhav/SVCD_on_a_Macintosh.html#crop

    With non-DV (or "unscaled" DV-like sizes) you can just crop and leave the Scaling box unchecked. Then the frame size changes.

    But you want a different output frame size after cropping the larger size.

    Maybe you could tweak the X/Y setting, too: I did a quick test with square pixel input and output and I did find a X/Y value that did what I wanted. ...but I used a lot of trial and error to find a suitable value and my initial good-looking calculation did not work universally.

    Maybe it is best ask this from the MPEG Streamclip author -- he might give you the definite answer how to precisely calculate the needed values and/or modify the interface or the guide to take this need into account.

    [I edited this post after I found out that my initial fix didn't work universally]
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  3. Member
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    Why are you cropping? If you intend the result for computer playback, just downsize to a widescreen aspect, like 640x360. If you intend to burn a DVD, just downscale the entire image to 720x480, author as an anamorphic DVD, and let your DVD player do the cropping to a pan&scan image.
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    I should probably clarify further...

    First the basics (not that you guys need it, I'm just going thru the process). HD resolution 1280x720 (and 1920x1080 as well) is a 16:9 display ratio and is square pixels. DVDs are 720x480, either as a 4:3 or 16:9 DAR, and are not square pixels.

    I'm trying to downsize from a 1280x720 16:9 HD source to an uncompressed 720x480 QT .mov that I can then drop in Compressor and make 4:3 mpgs. Somewhere along the way I will need to convert the framerate as well, it seems logical to do that at the same time as the resize. I will then author in DVDSP using the original .ac3 files demuxed from the HD source.

    I need to crop 160 pixels from both the L and R sides because 1280x720 is 16:9 and the show I'm working with (Family Guy) is 4:3. The area being cropped is useles black space. The resulting size is 960x720 which in theory sizes down perfectly to 640x480, a 4:3 ratio. But since I'm doing this to author a DVD I don't want 640x480, I want 720x480.

    I've found that if I resize FIRST from 1280x720 to 960x480, THEN crop 120 pixels of black space from the L and R sides, the result is a pretty decent 720x480. The 960 width and 120 pixel crop are arbitrary numbers arrived at by best guess. The ideal method would be to crop first then resize, which I am unable to figure out how do with MPEG Streamclip. MPEG Streamclip resizes first and then crops.

    I have no idea how to use the zoom feature. The couple times I tried it the results were totally unpredictable.
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  5. Member
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    I thought Family Guy, like all scripted Fox series, was broadcast in fullscreen 16:9. Are you trying to make 4:3 DVDs just to make 4:3 DVDs, or what? Again I ask, why are you cropping?
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  6. Member
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    Interesting approach. I just did some experiments with a 15 second HD TS clip that I use for this purpose of testing different settings. Unfortunately my clip's image fills the 16:9 frame so I can't tell where your black bars may appear. But the best outcome was when I chose Export to DV in Streamclip, clicked Better Downscaling and set my left and right crops at between 60-80. Higher crops stretched the picture horizontally. The resulting file is 720 x 480 and 29.97 fps.
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    AntnyMD, I'm not sure if I understand what you mean by fullscreen 16:9. To me, 4:3 = fullscreen, and 16:9 = widescreen. The video is 1280x720, which is a 16:9 ratio. There are 160 pixels on each side that are nothing but black filler. 1280 - 160 - 160 = 960 pixels of usable video. 960x720 = 4:3. I would like to crop the 160 pixels off each side for the reason that, well, because I don't know why I would want to keep it. For example, a store bought fullscreen DVD is 720x480, squashed down to 4:3, no pan-and-scan, and no massive black borders on the edges (not counting a few pixels of overscan distortion).
    Part 2 of my original question, what is a good non-compressed format to use? Apple None is missing from MPEG Streamclip. I would prefer not to use DV. I have 8-bit and 10-bit 4:2:2 uncompressed, I will probably use that.
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  8. Member
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    Originally Posted by cnelson87
    AntnyMD, I'm not sure if I understand what you mean by fullscreen 16:9. To me, 4:3 = fullscreen, and 16:9 = widescreen.
    By fullscreen 16:9 I mean a widescreen image that fills the entire 16:9 screen (as opposed to a widescreen image that is letterboxed in the 16:9 screen). So, a high definition fullscreen 16:9 television show like Arrested Development, versus a high definition letterboxed 16:9 film like L.A. Confidential. A 4:3 image in a 16:9 frame is what I call pillarboxed.

    Oh, terminology!
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  9. OK, I calculated the required scaling and cropping/padding based on the info and calculation examples in this page:

    http://www.iki.fi/znark/video/conversion/

    IF my calculations are correct, then you simply need to export & scale the 16:9 square pixel 1280x720 source as 16:9 NTSC 720x480 rectangular pixel DV and pad 4+5 pixels to the left+right and crop 3+3 pixels from the top+bottom. The result seems to be OK in practice, too.

    Now, MPEG Streamclip seems to automatically do that very padding and cropping when converting square pixels to rectangular so the user just has to tell it to scale the video (=basically what AntnyMD told you to do). BTW, MPEG Streamclip relies on the aspect ratio info on the link mentioned above so it should use similar calculations for the conversion.

    If you want to crop black borders off, then you could use a modest Zoom factor (105-110% or something like that). TV overscan will also do some cropping. The Zoom will be also crop from the top+bottom, but you have to do that if you want to preserve the aspect ratio. Enable Interlaced scaling if any part of the video is interlaced, or disable it if all of the video is progressive.

    On the other hand, if you want to output 4:3 NTSC 720x480 DV, then you'll have to crop 114+114 pixels from the left&right and 3+3 pixels from the top+bottom while exporting DV from MPEG Streamclip.

    DV is not the best codec -- that's why MPEG Streamclip author chose to use Motion JPEG as the default for .mov. I don't know why he didn't include an uncompressed output option.

    p.s. In my 16:9 calculations I used the following values:

    -source_sampling_matrix = 1280x720
    -source_actual_active_picture_size = 1280x720 (I'm not sure about this, anyone?)
    -source_pixel_aspect_ratio = (16/9)/(1280/720) = 1
    -target_sampling_matrix = 720x480
    -target_actual_active_picture_size = 710.85x486
    -target_pixel_aspect_ratio = (16/9)/(710.85/486)

    And as an intermediary result I got: resampled_target_sampling_matrix = 710.85x486 which must then be padded and cropped to 720x480.
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    Originally Posted by havema-1
    DV is not the best codec -- that's why MPEG Streamclip author chose to use Motion JPEG as the default for .mov. I don't know why he didn't include an uncompressed output option.
    Maybe because uncompressed output would result in enormous files, like ~25 GB for 30 minutes.
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  11. Member
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    This thread might be helpful to you:

    https://forum.videohelp.com/viewtopic.php?t=289113
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  12. Member
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    Thanks everyone for your suggestions / comments.
    I will email the MPEG Streamclip author with some suggestions for possible future features.
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  13. Member
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    Hi

    I've created a portrait video for display on a poster screen 1920 x 1080, I also want to create a version of this for my website (by not using flash).

    So far I have created the 1920 x 1080 video file. However my visual is narrower than this (more like 1920 x 720) therefore I have two black bars either side (the poster screen envelops these however on my website (the video hosted by vimeo) I cannot remove the bars.

    Obviously I cannot resize the 1080 to 720 because it just warps the video, and upon editing the embedding / iframe it just makes the content smaller within more of a black frame.

    I have tried the cropping tool on MPEG Streamclip however it is just a bit bonkers and jumps one way or the other, having tried adding and subtracting pixels on every side possible I gave up to try edit online with HTML but have not found the answer... hope it doesn't have to mean remaking the video with white background...................

    Any help greatly appreciated.

    kkrr
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