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Cropping a 720x480 Video to 320x320
crash447 posted 2008 Jun 02 18:09
I have never really understood how to crop video correctly. How much do I need to take off of a video if I am going from 720x480 down to 320x320? I know I am making this sound like an easy question, but I understand it probably is not. Even if it is not exactly 320x320 is fine, but something to get rid of some of the black would be a great start.

Thanks,
John



redwudz posted 2008 Jun 02 18:23
For what format? If DVD, you need to end up with 720 X 480 or 352 X 480 most times. If you crop off all the black and end up with something else, you will probably have to resize, besides you will have to re-encode if you resize or crop anyway. For Divx or similar, you can use most any framesize you want, though the codec may require multiples of 2 or 4 or 16 in the framesizes.

If it's a AVI type file like Divx/Xvid, try the cropping and resizing features in VirtualDub. Crop from all four sides if you want, resize if you need to.

EDIT: Since this is the Portable Video forum, what device are you resizing for, what resolution/framesize does it use? 320 X 320 seems a odd size if you are trying to keep the aspect ratio correct. :?



crash447 posted 2008 Jun 02 18:32
It is a palm centro and I am going to convert it to H.264/AAC. I do not really need 320x320, but with a 640x360 conversion I have tons of black and I really do not need 640x anyway. I have just never understood how much to take of the sides to get stuff to look right.


MOVIEGEEK posted 2008 Jun 02 19:27
It's best to encode in 320x320 from the source rather than clipping and reencoding.I would use Nero Recode or WME if your Palm supports WMV.You can also use TMPGEnc to make an MPEG-1 video in 320x320.
Tip:you need to select "keep aspect ratio" otherwise the video will be sqwished horizontally.



crash447 posted 2008 Jun 02 19:40
My sources is 720x480. My device is 320x320. I am using Nero Recode, but wanting to encode to H.264/AAC. I am not reencoding.


Noahtuck posted 2008 Jun 02 20:06
crash447 :
My sources is 720x480. My device is 320x320. I am using Nero Recode, but wanting to encode to H.264/AAC. I am not reencoding.

:shock: :shock:
:lol: :lol:

If you are changing resolution, cropping or going from one format to another, you are re-encoding, hence the name of the program you are using 8)



MOVIEGEEK posted 2008 Jun 02 20:28
crash447 :
My sources is 720x480. My device is 320x320. I am using Nero Recode, but wanting to encode to H.264/AAC. I am not reencoding.


Yes you are.
My Treo 700 also has a 320x320 display and I use 320x240 resolution video,the aspect ratio is preserved and no clipping is required.



Alex_ander posted 2008 Jun 02 23:43
crash447 :
... how much to take of the sides to get stuff to look right.

For any 4:3 fullscreen video (independently of pixel type) you want to crop exactly 1/4 of its horizontal size in pixels to keep proportions at 1:1 playback. In your case crop to 540x480, then resize to 320x320.



theewizard posted 2008 Jun 18 01:22
videos for many phones are 320*240, even on my voyager with a 400*240 display , video is 320*240

AFAIK the centro is setup to display normal qvga video, that is 320*240 even though the screen is 320*320.. thats for NON-vidoe use, phone menus etc..

convert/re-encode to 320*240 at 15 fps for the best results

set conversion to 360*240 and crop 40 pixels, 20 pixels on each side, this will maintain the correct aspect of your videos

I use SUPER to convert to 3g2 or MP4 15fps 240k video bitrate, 56k CBR audio




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