DV AVI to FLV - Squished video - aspect ration 4:3 really 3:2???

[Tfp]

Hi everyone,

We have a Adobe Premiere 2.0 Project that has 720 x 480 NTSC Mini DV footage. We export the video as uncompressed AVI with progressive interlacing. I import video into Macromedia Flash 8. I select resize in the advanced options. I set the width to 400 and to maintain aspect ratio. It changes the height to 266 making a total 400 x 266. The resulting encoded .flv file appears squished.

According to my math 720/3*2=480 therefore, 720x480 is a 3:2 ration and not a 4:3 ratio. Apparently Macromedia Flash 8 believes this as well.

Mediainfo tells me that my 720x480 files are 4:3 aspect ratio, fair enough, I override maintain aspect ratio in flash import and select settings of 400x300 which is a 4:3 aspect ratio. Resulting video appears to have proper aspect ratio.



What is going on here? How can 640x480 be 4:3? I measured 720 x 480 width in media player with pixel ruler and sure enough, the "720" wide is actually "640" wide.

I know how to work with this stuff now, although Flash 8 doesn't but I just want it to make sense in my head. I did a bunch of Google searches and stuff but could not find answers so here I am...

Thank you

[gadgetguy]

You're confusing resolution with aspect ratio. miniDV/DV-AVI uses non-square pixels for either widescreen or 4:3, but the 720x480 resolution is the same in both cases.

[manono]

Yep. 720x480 is, as you discovered, 3:2 or 1.5:1. The 4:3 DAR (Display Aspect Ratio) tells the player how it's to be resized upon playback. For 4:3 encoded videos, that's 640x480 (480 x 4/3 = 640), or any other similar 1.33:1 ratio (like your 400x300). As gadgetguy says, it's stored as non-square pixels which become square again after the resize.

[Tfp]

Hmm, I wonder why Macromedia Flash doesn't pick up on that then. You would think it could handle that. I wonder how many people squish there video with that and don't even realize it.

It is gonna take me a minute to reflect on what you guys said.

[gadgetguy]

I wonder how many people squish there video with that and don't even realize it.

Many. Another common item overlooked is that DV-AVI is interlaced and needs to be properly dealt with to maintain the interlace and keep the correct field order through the final encode.