Does an NTSC (TV) AVI contain both fields?

[davexnet]

Hello, I know that a frame of SVCD at 480*480 contains
both the odd and even fields, but is there an equivalent
to this in AVI?
For example, if I capture NTSC of a pure interlaced show,
(shot from a TV camera) into 29.97 AVI, what do I get?
If it only gets one field, then half the info has been lost?

Please advise.
Dave

[dodge]

As i understand it dividing the picture into two fields or interlacing is just to reduce the bandwidth of the video signal, if you capture somthing digitaly each frame will be captured (progressive) containing feilds a and b.

[davexnet]

Thanks for the info. I was looking for a little more info,
and I came across http://www.lukesvideo.com/interlacing.html

This clarifies it by stating that it applies to anything
captured at full vertical resolution (480 or more horizontal).

It seems then that AVI and SVCD behave similarly. For example,
regular VCD (352*240) only contains one field.

Regards,
Dave

[khp]

Support for interlaced video is up to the codec.

Older versions of divx does not support interlaceing. AFAIK divx5.03 and XVID does support interlacing. But I haven't tried it.

[davexnet]

Thanks for the info re: the codecs.

Some of the confusion (I think) is that it seems Virtualdub
treats *any* AVI regardless of V. resolution as if it really
had two fields per frame even if it (technically)doesn't.

For example, a wide screen avi 640*272, due to it's
vertical resolution of 272, It obviously doesn't have enough
info for two complete fields (240*2 for NTSC) but
the deinterlace filter will still do it's thing.
I guess Vdub just separates the odd/even lines
no matter the size.

It seems like it's only a factor at MPG (vcd or svcd) creation,
because the goal; is to display the clip on the TV. -
But then, we trust Tmpgenc tp do the right thing !

Dave