Pixel aspect ratio

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pchin
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Joined: Thu Aug 05, 2004 11:15 am

Pixel aspect ratio

Post by pchin »

Dear Lost Marble,

it would help a great deal if it was possible to be able to set the pixel aspect ratio in the project settings or render options. Makes it a lot easier to render anamorphic formats directely from MOHO.
Patrick Chin
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lawson&whatshisname
www.whats.nl
jeff
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Post by jeff »

Patrick,

I know what you're saying.

Rather than introducing the concept of pixel aspect ratios, I would put it like this: it would be nice to be able to work on a project at, say, 1024 x 576 pixels then export it as 720 x 576 pixels (these are European figures) for output to DigiBeta and have the shape of the images squashed as a result. These figures would give you a correct anamorphic image for 16 x 9 broadcast.

At the moment, if you change the pixel dimensions in your project settings, the geometries of your artwork don't alter.

For now, as a workaround, you can of course use software like the freeware prog. IrfanView to batch re-size your files.

Jeff
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pchin
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Post by pchin »

Hey Jeff,

I think that if you only change the resolution the person on the receiving end would have to manually restretch the footage to match his or her anamorphic project. This is not a very complicated operation, but would still add another step and more rendertime to the whole process. With pixel aspect ratios the whole process is automated and does not require more rendertime.

I think MOHO might be facing more of these type of requests as it becomes more and more professional (hooray!). And MOHO users start using it more for broadcast or even film projects. (in which the concept of pixel aspect ratios is quite common)
Patrick Chin
--------------
lawson&whatshisname
www.whats.nl
jeff
Posts: 127
Joined: Fri Aug 20, 2004 12:32 pm
Location: London, UK
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Post by jeff »

Hmm, maybe I am being dense, but I am not sure I see your problem, Patrick. I can only say from experience that I usually keep everything at the correct 16 x 9 shape throughout a project. It's only after all the creative work is done and at the very last stage, transferring to tape, that an anamorphic image is needed. I have only done a few bits and bobs in Moho for broadcast use and I worked in Moho at 512 x 283 pixels. When I was ready to render, I upped the project settings to be 1024 x 576 pixels. I output files at this resolution. My video card resizes these files on the fly to be 720 x 576 pixels and thus turns them into standard anamorphic broadcast images which can be output to Digital Betacam which I hire in. If it didn't, I would use Photoshop or IrfanView etc. to batch process them to be 720 x 576. For cinema or HD use, of course, I would re-size the project to be 1920 x 1080 and then anamorphic doesn't come into it. I haven't actually done final work at HD resolution, but it is very easy; all I would need to do is burn the files at that resolution on to CD or DVD ROM and give them to a facilities house who would then put them on to D5 tape etc. or even film.

As far as I know, there's only one reason to ever use anamorphic images and that is when transferring to a D1 format VCR such as Digital Betacam. Unfortunately, they can only record and playback at 720 x 576, so in order to get the letterbox shape of 16 x 9, without throwing any picture away, they need a squashed i.e. anamorphic image.

Does this make any sense? Maybe there's another issue which I am overlooking, in which case I apologise.

I have written some notes on widescreen usage for UK animators and also an article about pixel aspect ratios on at:

http://animationpost.co.uk

(you need to click on the "Pixels and Pegbars" section).

Let me know if I am just talking crap, or whether this helps.

Best regards,

Jeff
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pchin
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Post by pchin »

Hey Jeff,

I quickly read through your article and I think we basically agree on this issue.

I think it comes down to this: "The size conversion may not be necessary if you are fortunate and have a video board that will automatically re-size the incoming image correctly." (from your article;-)

I would like Moho to do this. That's all.


Nice bunch of articles by the way, cool of you to write that stuff down. All this technical stuff can be very confusing. It can still confuse me sometimes. Thanks for reacting to my posts.
Patrick Chin
--------------
lawson&whatshisname
www.whats.nl
jeff
Posts: 127
Joined: Fri Aug 20, 2004 12:32 pm
Location: London, UK
Contact:

Post by jeff »

Phew. We're agreed then Patrick!

I suppose you could group all your Moho layers into one then just apply a horizontal scaling factor. Not very elegant, but would probably work.

All the best,

Jeff
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