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-   -   Correct Photo Aspect Ratio for slideshow (https://www.dvinfo.net/forum/non-linear-editing-pc/479990-correct-photo-aspect-ratio-slideshow.html)

John Gerard June 6th, 2010 03:26 PM

Correct Photo Aspect Ratio for slideshow
 
Hello,
I have tried to post this message a couple of times.
You guys have helped me before in setting up a good workflow for down converting HDV video to SD DVD.I use video Dub to convert the final Premiere Pro project to AVI and then import that in to Encore. This creates really good quality DVDs.
I am currently working on a project that will contain mostly Photos with a few MP4 video clips that will be displayed on a HDtv but in the DVD format. What is the best project setting to use in Premiere Pro CS3? HDtv, SD etc. And what size should I resize the photos to in Photoshop and what aspect ratio should I use? I want the final project to be displayed in the 4:3 format on a HDtv? I know that the size of the picture can be a little bigger than what would be displayed on a tube TV.

Thanks for your help,
John Gerard

Chris Harding June 6th, 2010 09:40 PM

Hi John

The rule for photos is very simple. The still photo needs to be the same height as your video project but to get the correct width you need to multiply the standard width (720 in SD) by the pixel aspect ratio which is usually 0.9091 : 1 so your still needs to be 655x480 and not 720x480 to fit the frame correctly.

If however you are working with widescreen the PAR increases to 1.21 : 1

So 4:3 video I find that cropping the still to an aspect ratio of 1.365 : 1 is pretty close and then you can simply resize it to suit (655x480 for NTSC 4:3)

Chris

John Gerard June 7th, 2010 11:19 AM

pixel aspect ratio
 
Hi,

So, for an HD tv what is the Pixel Aspect Ratio? I read on the net that the picture size should be 720x547. Is that then not correct? The hard part is that the photos are all different sizes to begin with. So if I size all photos to the same size it appears that not all the photos will be displayed correctly. I think I need to learn how a photo is interpreted in digital form and in photoshop.

John Gerard

Martin Mayer June 7th, 2010 12:18 PM

Just to be clear: there is no flavour of HD that uses the 4:3 aspect ratio. HD video is always 16:9.

However, a widescreen TV (16:9) is not necessarily HD: there are standard definition (SD) widescreen TVs. Not sure what you mean by a "tube TV".

I mean no disresepct, but I suspect you're using "HDtv" to mean 16:9, and "tube TV" to mean 4:3. You're going to get confused if you do that, and confuse the responses you get here, too.

Adam Gold June 7th, 2010 01:25 PM

The problem here is that we have a variety of sizes, formats and aspect ratios, even within formats. You can fit a square peg into a round hole if the hole is big enough, but if the hole's too small... well, you get the point.

Still photos are usually 1.5:1, going back to the 35mm days, when the frame for still 35mm film was 24 x 36 mm. But of course this could be portrait or landscape, which complicates things for video, which is always landscape.

In HD, the Pixel aspect ratio could be either 1.0 for 1920 x 1080 or 1280 x 720, or it could be 1.33 for 1440 x 1080. The aspect ratio of the frame is always 16:9 in HD, or 1.78 (approx).

Standard def is 4:3, or 1.33, with a PAR of about .9. So neither video format fits the still photo, so you will always end up doing some combination of cropping and zooming, letterboxing or pillarboxing. Unless you want to stretch them and distort them as if you are looking at them in a fun-house mirror.

Assuming you are doing no moves with these pictures, if you are editing them in an HD project, set the width of the photos in Photoshop to 1920px. If it's an SD project, set it to 720px. Tell Photoshop to preserve the aspect ratio or proportions and you should be all set.

Note: CS3 hates stills and will crash on you. A lot. You can minimize this by saving your stills as PNGs when you resize them instead of JPGs.

Note2: All this resizing is largely irrelevant in Premiere except that the goal is to have the still be just big enough so that you don't lose any resolution. But you can crop, stretch, zoom, all within Premiere to make it look exactly the way you want. I use an interesting free app called Irfanview to resize, rename and convert all my stills in batches; If I recall correctly all you do is tell it to make the long side 1920 and push "go." But all your real manipulation should be done in Premiere.

If I understand your original post correctly you:

1) Will be displaying on a 16:9 TV
2) From a standard DVD
3) But want it to be in 4:3 (why?)

Is this correct?

John Gerard June 7th, 2010 08:24 PM

pixel aspect ratio
 
Hi,

Thanks so much for the reply. You are 90% correct in interpreting my post. I, at first assumed that I wanted to convert my pictures in to something like a 4:3 format. Maybe this was wrong thinking. I have not used photos much in my work. I really meant to say that I do not want my photos to look stretched out as in a HD Widescreen format. I am thinking that there must be a formula in figuring out the correct pixel dimensions to resize my photos? So as you put it look the best if not perfect on the TV screen. Not being confused with Pixel Aspect Ratio. I have read that one needs to resize the photo in a way to compensate for the non square pixels in the different formats. I just don't know the formula for this? If a LCD HDtv has the Square pixel aspect ratio then I would think that I would not have to do any special conversion. Although, it depends on what Virtual Dub and/or Encore is doing when it writes the final project to DVD? Is Encore converting the final project into .9 Pixel aspect Ratio or 1.21 Aspect Ratio or is Encore leaving it as Square pixels? I would like to have the computer resize the photos to a size I can use so I do not have to manually resize each one in premiere pro if that is possible. I realize that some photos are taken in Portrait and some in landscape mode. Each one with different pixel widths as well. I realize each photo might not be the exact same size, screen dimensions. I just want them to look relatively close to the actual photo dimensions to the viewers eye. I am going to have close to 100 photos. I will have some short video taken on many different types of cameras. I do know it is mostly MP4 video. What I don't know is if any video cameras are HD or just SD format.
I could probably do the project in SD but even in SD the screen size is different on a HD TV(LCD tv)(wider and i think a little taller screen size) than on a standard tv, what I call a Tub TV. I would like to fill as much of the screen as I can. As I talked about I learned that it is best to edit my HDV video in 1440x1080I and then convert it to SD in Vertual Dub. Then import to Encore. I am just think that this might be the best way to get the best quality out of this project. But then again I could be wrong. I am assuming you are saying that an LCD HD tv has a Pixel aspect ratio of Square pixels?
I will reread your post to better understand what you are talking about. Oh, I do use Ifranview a lot and really like the program. I also can create custom macros in Photoshop CS3 extended.

Thanks,
John Gerard

Adam Gold June 7th, 2010 11:56 PM

I think I get where you're wanting to go with this, and maybe you are over-thinking this a bit and making it harder than it needs to be.

The HDTV itself doesn't have a set PAR; it merely plays what you tell it to and generally does a pretty good job unless it gets confused.

So let's say you're using a proper HDTV with a 16:9 display. You want your photos to display without any stretching (excellent) but you also want to fill the whole frame of the TV. So you're going to need to crop. For landscape photos you may not need to crop much, because they are already wider than they are high, just not as wide, proportionally, as an HDTV. For Portrait mode photos you will need to crop a great deal off the top and bottom as you can't stretch them or turn them sideways.

So really, the only thing to do is edit everything in an HD project, 16:9. Make all your photos 1920px wide in whatever program you like, but make sure the proportions are maintained so as to avoid stretching or squashing or other nasty distortions. The landscape photos will probably end up somewhere around 1200px tall, which means a little bit of cropping on top and bottom. The Portrait ones will probably be in the 3000px tall range, so you'll have to crop them a lot off the top and bottom. But in either case the amount you crop off top and bottom may not be the same, so it will take some effort and artistic judgment on your part to make it look nice -- no way around that.

Once the project is done, just go File > Export > Export to Encore. No need to use Virtual Dub or any other third party program. CS3 does a fantastic job of going straight to DVD from an HD timeline. This way you will have the highest quality source material you can then render to any format you wish.

I've done quite a few projects in CS3 using stills and this is what I usually do. Use Irfanview's batch conversion utility to take all your photos and make them all 1920 wide PNGs. Then import into Premiere and adjust as necessary. If you thought you might want to zoom in on them or add other motion effects (panning, tilting, rotating, etc) then you could make them bigger to allow for this without losing resolution.

Doug Bailey June 30th, 2010 08:36 AM

Hi John,
One of the answers to different size photos is to use a larger photo for the background (maybe B&W) with a lower opacity. Then drop the different size photos onto this. This gives continuity and blends it all together.

An example of someone's life could be a larger size lower opacity old house as the background, with more recent images of the person getting married, playing golf, fishing etc in different sizes.

I saw a slide show like this a while back with music and birds singing and it stuck in my mind as something beautiful to create.

Hope this helps & best of luck.
Regards,
Doug.
www.BaileyNatureGallery.com


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