DVD 16:9 aspect vs. Web Widescreen Aspect

[Chris Owen]

I am probably making this more difficult than I need to, and as a result I am getting very confused about aspect ratios and output for TV / DVD / web.

I understand that what is displayed on computer monitor is displayed in square pixels and this is different (retangular) on a Television set.

A little background on what I use and what I am getting ...
I have been using Vegas and After Effects for a long time to edit video for web for my clients. This has always been client provided 4:3 video footage that I just edited using a 1:1 square pixel 640x480 project template. I want to get into shooting my own "nature videos" in widescreen format to display both on the web and on DVD. The idea here is to have the DVD fill the screen on widescreen format TVs and "letterbox" on standard TVs, AND output to display widescreen on my website (maybe in my portfolio section). Everything @ 24p. I intend to get a new XL2 in the VERY near future to start learning to shoot.

What is driving me crazy right now ... I am in the middle of designing my new site. I am setting up the display areas for streaming video and run into a brick wall. For my website, I start resizing areas to accomodate a derivative of 720px X 480px (ie. 480 px X 320px). It doesn't look quite right so I decide I am going attempt a little math (I've never seen so much smoke in my life!) and figure out that 1.78 times 480 is 854.4 (854x480 looked right in the layout on my site for widescreen). OK, so widescreen isn't 1.78:1 like I thought? It is 1.5:1 (480 times 1.5 is 720)? ... I thought widescreen was 16:9, which equals roughly 1.78:1. (In Vegas, one of the property templates is NTSC Widescreen @ 720x480)

Since I do not yet have my camera (probably a month or so away) to figure all this out on my own, I thought I would go ahead and get my new site built and ready to display my <in the distant future> video projects. Then I ran into this problem - my 17 brain cells just can't handle this.

I am guessing it is something simple that I am trying to make difficult. Do I just layout everything on my site to a derivative of 720x480 and quit messing with this "math" thing (it almost hurts to type that word)? Or is widescreen not 720x480?

I hope this makes sense, I have so many thoughts going through my little head trying to figure this out while I am typing ...

[Tim Johnson]

pixel aspect ratio is wrong i believe

i found out that in order to get the right sizes in graphics (which use square pixels) you must use the following dimensions:

864x480

hope this is of use to you! (google is your friend)

hell, if you were doing it in photoshop cs2 theres even an option in new document menu to choose pixel aspect ratio lol

[Chris Owen]

Thanks for replying. Can you elaborate?

EDIT : Just saw that you did elaborate after I posted :)

I'm doing the whole layout in Flash (unconventional, I know, but its how I started and old habits die hard). Thanks for the tip on still images imported ... that little tip, I am sure, will be very useful in the future.

[Tim Johnson]

i found this info at

http://www.mir.com/DMG/aspect.html

it turns out is actually 864x480 after checking for myself using printscreen?!

[Chris Owen]

Originally Posted by Tim Johnson

i found this info at

http://www.mir.com/DMG/aspect.html

it turns out is actually 864x480 after checking for myself using printscreen?!

Thanks for that link ... the chart actually shows your first dimension (854x480) as correct for square pixel images for NTSC graphics in wide dv. That link really clears a lot of things up ... sort of. I'll have to read and re-read a lot of it.

[Tim Johnson]

Originally Posted by Chris Owen

Thanks for that link ... the chart actually shows your first dimension (854x480) as correct for square pixel images for NTSC graphics in wide dv. That link really clears a lot of things up ... sort of. I'll have to read and re-read a lot of it.

if you google "864x480 ntsc" you will find alot of results...

i compared them on my monitor and 864x480 square and 16:9 widescreen are one and the same :P

[Gian Pablo Villamil]

Widescreen is always displayed as 16:9, so 854x480 is right.

The confusion is that DV (and DVD MPEG2) is always *stored* as 720x480. If it is to be displayed as 4:3, then the pixels are scaled by .9091 horizontally (pixel aspect ratio). If it is to be displayed as 16:9, then pixels are scaled by 1.21 horizontally (approximately). Basically the DV and the DVD MPEG2 standards always store the same resolution video, but use different sized pixels depending on whether the output is WS or 4:3.

So disregard 720x480 which is purely a storage format, and focus on your desired display aspect ratio 16:9 (1:1.7778).

So the following ratios are all good for widescreen 16:9:

1280x720
854x480
640x360
etc.

There are some minor differences between mathematically exact 16:9 and what is actually achieved by scaling up DV, but don't worry about it.

[Chris Owen]

Originally Posted by Gian Pablo Villamil

Widescreen is always displayed as 16:9, so 854x480 is right.

The confusion is that DV (and DVD MPEG2) is always *stored* as 720x480. If it is to be displayed as 4:3, then the pixels are scaled by .9091 horizontally (pixel aspect ratio). If it is to be displayed as 16:9, then pixels are scaled by 1.21 horizontally (approximately). Basically the DV and the DVD MPEG2 standards always store the same resolution video, but use different sized pixels depending on whether the output is WS or 4:3.

So disregard 720x480 which is purely a storage format, and focus on your desired display aspect ratio 16:9 (1:1.7778).

So the following ratios are all good for widescreen 16:9:

1280x720
854x480
640x360
etc.

There are some minor differences between mathematically exact 16:9 and what is actually achieved by scaling up DV, but don't worry about it.

Ahhh, thanks! So I should be fine to layout my video placeholders on the site as 480x270?

After I render from Vegas to uncompressed avi using the Vegas NTSC widescreen template, I will import to Sorenson (just for the web video). Output from Sorenson 4 to H.264 flv at the dimensions I will use on the site (480x270)?

[Gian Pablo Villamil]

480x270 is fine, that is a 16:9 ratio.

Why not render straight from Vegas to Quicktime?

[Chris Owen]

Originally Posted by Gian Pablo Villamil

Why not render straight from Vegas to Quicktime?

I'm going to embed everything into a flash site to progressively stream flv files. I've found that its easier for average folks to update to flash player 8 with install on demand than to have them go to Apple's website and download and install iTunes with QT.

I do plan to also have a seperate link to DL QT files for folks that want the vids on their hard drive. In other words there will be a "play now" button that will stream the flv in a player integrated on the site and a "download" button.