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-   -   Crop before output? (https://www.dvinfo.net/forum/flash-web-video/2310-crop-before-output.html)

Chris Hurd June 6th, 2002 10:48 PM

Crop before output?
 
I'm just curious... given the difference in image composition between video on a consumer television (where the viewable frame is limited to the action-safe area) and video for the web (where the entire frame is viewable), are any of you cropping your web video image down to the action-safe area so that it appears the same as video on a consumer television? Or are you using the entire frame, even though you normally don't see beyond the edge of what the viewfinder shows you when you shot it in the first place. Thanks,

Rob Lohman June 7th, 2002 05:57 AM

I at least crop vertically, but that is more due to widescreen
things than that. You do ask an interesting question though,
theoratically you do want everyone to have the same experience,
so it might be interesting to do.... interesting!

K. Forman June 7th, 2002 06:35 AM

I leave it in its natural glory. Unless there is the odd flickering at the edges.

Adam Brooks June 7th, 2002 09:57 AM

Part 1

There are 2 reasons to crop video for the web.

#1. You shot in 4:3 and you want to look like 16:9. You could crop it as much as you like. you could make it 16:2 if you wanted too. It doesn't really matter since you don't have a standard to stick too.

#2. Look at the DV image you shot and notice that in some editing systems you see that there is a black line or group of lines either on the top bootom left or right . Depending on how the footage has been imported into the system. The ITU 601 Standard is 720x486. and DV is 720x480 . What happenedd to the other 6 lines? Well they are filled in with black.
RealSytems for example has a hard time encoding when there are black lines that don't change on screen. So you want to crop them out. It also makes it look right.

Part 2
There is no action safe or title safe for web video. So you are using the entire video source when you encode. So lower thirds and graphics go edge to edge on the screen. Besides when you create a video that's 160x120 you want to start out with as much picture as possib.e.

Adam

Peter Wiley October 13th, 2002 05:22 AM

The instructions that come with HipFlics (QuickTime compression tool) actually recommend cropping to help get the final file size as small as possible. I think cropping for this reason is a standard practice.

Rob Lohman October 14th, 2002 06:18 AM

Agreed peter. I want it wide screen and I really do not have to
encode the black bars... That is a waste of filesize. Your computer
will auto black it when played fullscreen... Handy dandy.

Nathan Gifford October 14th, 2002 08:33 AM

I only crop out the black lines (every little bit helps the bandwidth). I haven't shot anything 16:9 because I do not have anamorphic lens for the XL-1. My fear is that someone will need some footage 4:3 and all I will have electronic 16:9.

Oh, I am using Real.

Later,

Rob Lohman October 16th, 2002 12:29 PM

I'm not shooting 16:9 either Nathan... I am framing for it though.
And I'm adding black bars (to get a 16:9 frame) to the final output.
If I'm going down the web delivery route I'd either crop those
black bars out or crop the original footage (which is the same).

I prefere to watch it in widescreen, and as said, I frame for it
too whilst shooting. If someone still wants 4:3 I can go back and
"remove" the black bars (ie, keep the original footage and not ADD
the black bars ofcourse) and output it again, done.

Josh Bass October 16th, 2002 03:07 PM

I've been meaning to ask this, and now seems like as good a time as any. With film festivals in mind, should you crop to the action safe? I don't what smaller festivals who don't play film use (Digital light projector, vcr and big TV, no idea). I wouldn't worry except that I'm pretty sure there's some naughty errors that could be eliminated by cropping.

Rob Lohman October 17th, 2002 08:18 AM

I have got no idea... anyone else?

Charles Papert October 17th, 2002 08:29 AM

Josh:

If I understand you correctly, you are talking about cropping (i.e. removing the area outside of safe action) and then resizing the result to full screen for NTSC playback (monitors, projectors)? This means that on a regular TV, you are likely to lose picture since most display a somewhat overscanned image (part of the image is inside the bevel, unable to be seen). The reason overscan was created was to eliminate potential black edges in case a picture tube started to shrink. Things have gotten a lot more complicated in recent years with flat screen TV's and projection that show a lot more of the image. For this reason it is best to always protect the full image from things like boom mikes and flags since they may show up here and there.

You may be talking about something else entirely, though...?

Nathan Gifford October 17th, 2002 11:30 AM

I don't see the advantage to cropping to the safe action area. Computer CRT screens are different than regular TVs. Most Reals, QTs, etc. are already shrunk in size so there is little chance of running into an overscan problem.

However, I always pay careful attention to these areas and create my videos with those areas in mind. You never know when someone may want one for DVD or something.

Josh Bass October 17th, 2002 12:45 PM

You got it Charles, you steadicamin' maniac. Exactly what I meant. I guess the rule is play it safe, period.


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