What makes an AVI clip 16:9 aspect ratio ??

[davehewy]

I have batch captured an hour of DV tape from my Canon MV600i using VideoStudio7.
I moved my project to VS8, setup the project to use non square pixel rendering,and as I filmed this in 16:9 all the clips appeared correctly in widescreen EXCEPT 1 !
Right in the middle there is one that is not reporting to VS8 that it is 16:9, and checking the properties compared to the other clips this is confirmed.
How can I make this clip 16:9, is there a bit or something that flags the aspect ratio?
Thanks
dave

[underwurlde]

Hmmm,

I may be wrong but my experiences with aspect ratios are thus:

The frame size determines the aspect ratio =
(H pixel size / V pixel size):1

Plop existing AVI into GSpot & calc aspect ratio based on above.

So, if you want to MAKE something a certain aspect ratio, note what GSpot reports, & use VirtualDub to convert to a new resized image whose new H/V pixel sizes are a ratio of 16:9, i.e. 1.77777:1 aka DVD Widescreen (British)
e.g. resize to something like 640x360

Hope this helps in some manner,


Andy

[davehewy]

Thanks Andy - that's most helpful.
The other alternative I suppose, is to output the full AVI movie as 4:3, then, as I have been doing before VS8, use something like TMPgEnc to convert to 16:9.
Do you think there'll be any loss of detail doing this instead?

Cheers

Dave

[underwurlde]

OK

converting 4:3 -> 16:9
i.e.
converting 1.33:1 -> 1.77:1
i.e.
converting (for example) 640x480 -> 640x360

As you can see the original vertical size is larger so I guess there must be some loss of data when resizing.

However..
The orignal 4:3 sould appear squished when played due to your non-square pixel capture approach and then resizing to 16:9 should un-squish it and hence no loss of data???!!!!

Does this sound right to you? All you can do is try it out of course....

Aspect ratios can be a real head-scratch!

Andy