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Square or non square pixels

Mar 29, 2013 8:47 AM

I am very new to After Effects and am completely unsure about which composition and preset Settings to choose. I want to create a slideshow to view on a SD LED TV although I have no idea which preset to choose: PAL DV, PAL DV Widescreen, PAL DV Squarew Pixels, PAL DVWidescreen Square Pixels.

 

Should I be working in 720x576, is it okay to view on widescreen TV??

 

Thanks in advance

 
Replies
  • Currently Being Moderated
    Mar 29, 2013 5:57 AM   in reply to Curly12378

    The actual SD broadcast spec always has anamorphic pixels. The square pixel equivalents are only meant for working easier. Whether you use widescreen 19:9 or 4:3 is entirely your choice. In any case, you might wanan do some reading on teh matter on a more general level...

     

    Mylenium

     
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  • Currently Being Moderated
    Mar 29, 2013 6:42 AM   in reply to Curly12378

    It is always best to work with square pixels. It is also always best to work at the maximum frame size you can reasonably expect to have need to use. For most projects today this means HD. The last decision is what frame rate to use. In PAL standard countries the minimum standard frame rate is 25 fps. Everywhere else the minimum standard is 23.976. There are other frame rate considerations for your main project that involve the kind of motion you are going to use. Generally speaking you get smoother motion with less chance of jittering or stroboscopic effects with higher frame rates.

     

    That was a lot to throw out at you all at once. Take a deep breath, I'm going to throw you some more. It's time to talk about source materials. It's always best to always start with the highest quality source material you can for your project but, now read this carefully because you are interested in doing a slide show, it is always best to size photographs and other artwork like Illustrator files (vector art) to a size that matches the size in the final project or is just slightly larger.

     

    What does that mean? Let's talk about your slideshow. First of all I would not consider working any project in Standard Definition any more. There are very few displays that are only 720 pixels wide. Even phones have higher resolution screens than that. My minimum size for any movie is full HD, 1920 X 1080. I also work mostly at 29.97 fps because it gives me more freedom with motion. We'll talk about sizing your slideshow for distribution later. For now let's talk about your slide show and the images you are going to use in it.

     

    So you've decided to do the slide show at 1920 X 1080 using the (PAL Standard) 25 fps setting. You've also shot all of your images with a 16 MP camera in Camera RAW format so you are starting with High Quality originals. You're processing your original photos in Photoshop to crop, color correct, and touch up. What size do you use for your final export. The originals are probably close to 4912 x 3264. That's 2.5 times larger than a standard HD frame size. If you are designing your slide show to show the full image at some point then your images can be resized in Photoshop to 1920 pixels wide. You should do final image sharpening and adjusting there. If, on the other hand, you want to push in on your photographs to see some details on the photos you must consider the final framing of the move on your photographs. At the original 4912 x 3264 frame size you could push in to about 1/4 of the picture without any problems. You can estimate the safe framing of your photographs by setting a fixed size to the rectangular selection tool in Photoshop and dragging it around your image. If you want to move in to show more detail than you see in this preview then you should scale up your photos in Photoshop and do your best to fix the scaling artifacts and improve the image there.

     

    Why don't you want to just use your photographs at full resolution? Because Photoshop will do a much better job at scaling your photos than you can do in AE and because your project will easier to work with and faster to render.

     

    Now let 's talk about delivering your project. You should always save your project with all of the source files. An AE project file does not contain any source footage. There's nothing in there but pointers to the original source footage. If you move the original footage, or don't save it then your project file is in a little trouble or completely ruined. You have two options for rendering your project to a delivery codec. The first is to render the project to a production codec that is lossless or nearly lossless. This is good for storage and, if you are delivering to several different formats or may need to do so in the future, this is the best first step. Once you have your Lossless original rendered you render a delivery version with the appropriate software. You should NOT use After Effects Render Cue to render to a delivery format. Highly compressed GOP compression like h.264 require multi pass compression do to a good job. You need specialized software for that. Fortunately Adobe supplies the Adobe Media Encoder with After Effects and it is very good at that job.

     

    Another advantage of the Adobe Media Encoder is that you can load your After Effects project file directly into the Adobe Media Encoder and render your delivery product there. This skips the first render and, for many projects is sufficient. If you have SD and HD output requirements you can set up the AME to render both at the same time using standard presets. This will also save you time.

     

    I hope this helps you figure out the best workflow. Good luck on your AE journey. I've been on it for more than 20 years.

     
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  • Currently Being Moderated
    Mar 30, 2013 12:58 AM   in reply to Curly12378

    You are always safe with the presets. DO NOT create custom non square pixel comps unless you know exactly what you are doing. 99.9999999% of the time custom pixel aspect ratio projects are wrong.

     

    AE will handle all of the pixel aspect ratio conversions automatically. Always work with Square Pixel Presets unless you specifically know that your project requires something else.

     

    Video displayed on the web is ALWAYS square pixels. Photographs taken with every digital camera I have ever worked with are always square pixels. Video, on the other hand, can be just about anything. You must know how your original video was shot. Most of the time AE properly interprets video from cameras so there's very little chance that your video will be distorted if you bring it into any square pixel or any non square pixel project. You can drop any video from any standard source, no matter what the PAR of the original, into a square pixel composition and AE will correct for the PAR difference and give you an undistorted image. It may be the wrong size for your composition, but it will not be distorted. To fix the size simply scale it up or down to fit keeping the X and Y scale values identical. If you start pulling down on the PAR options you're just going to end up with distorted images. Circles will be ovals. Squares will be rectangles. Don't change the PAR of a comp.

     

    When your project is ready to deliver Adobe Media Encoder will properly scale and fit any format into any other format without doing anything but choosing a preset. It's fool proof for nearly any application. The only exception is when you need to render projects for non standard digital displays like scoreboards, LED signs, or web banners.

     

    Here's the Comp Presets:

     

    Screen Shot 2013-03-30 at 12.24.11 AM.jpg

    Anything in Blue is a good standard working size for a composition with square pixels. The presets in Green are for output to film or cinema projection. The presets in yellow are what I use for all of my standard definition only projects but I have not done a SD only project in at least 5 years. There's no point. They haven't built a standard definition TV that anyone's bought in 5 years and TV stations in the US are not required to broadcast SD signals any more.

     

    The remaining presets are all rectangular pixels. They are useful ONLY if you have a specific request or a specific need to render back to a camera codec and camera frame size. Otherwise they are completely useless in any production workflow that I can think of. If you have some particularly difficult green screen footage shot on HDV or DVCPRO HD for for example you may want to pull your key in a comp that matches the footage so that the keying can work with the original pixels but that's the only time that you may gain a very slight advantage using a non square pixel comp for production. I've never had the need.

     

    You asked about the disadvantages to working in HD but viewing in SD. The only one is the extra render pass. When you're watching broadcast tv in the US your set is getting a HD signal that is either 1080 or 720 i and the receiver is downsizing it to SD for viewing. If you feed the signal from a BluRay player to a SD tv it is downsized to fit. If you use Apple TV or your X-Box to view NetFlix or YouTube and you pick HD content it is downsized. If you use Encore or any DVD authoring app to burn a DVD of your project you'll get a SD 720 rectangular pixel conversion of your HD material. The DVD authoring program will either automatically detect if your project is widescreen or if it is 4:3 or it will give you the choice. Either way, you'll get a better end result by giving the app HD material to digest rather than SD because the compressor is going to have more data to sample and compress.

     

    I hope this helps. Let's summarize. Use the Square Pixel presets for all projects unless you specifically are required to use another format to deliver to specialized content to a specialized playback device. NEVER mess with the PAR setting in a comp window. I don't even know why it is selectable. No one has ever shown me a legitimate reason to set a any comp to a non standard PAR. And lastly, use an encoding program like Adobe Media Encoder to render your final product for delivery.

     
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