why is NTSC Half D1 352x480 instead of 360x480?

[mracer]

If D1 and NTSC DVD resolution is 720x480, why is half D1 352x480? It seems like it should be 360x480. I want to make half D1 DVD's and this is confusing me. Maybe I am all mixed up on this subject.

[andkiich]

Don't forget that an acceptable, but often forgotten fact that 704x480 is also a valid DVD resolution.

If you double 352, you'll get 704.

[Sulik]

360 is not a multiple of 16. It would have to be 352 or 368.

[ronnylov]

And the actual picture area on a 720x480 DVD is closer to 704x480 (surrounded with black borders on left and right). Just crop 720 width to 704 width and then resize to 352 width.

[lordsmurf]

Half D1 is truly 352x480
Full D1 is truly 704x480

720x480 is a bastard resolution.

[themichael]

I thought Broadcast D1 was 704x480 and Full D1 was 720x480.

[mracer]

Thanks for the info everyone. Does anyone know why DVD is 720x480 instead of 704x480? It just seems like it should have been the same as D1.

[Sulik]

Both 704 and 720 are valid DVD resolutions.

[duhmez]

it must be a multiple of 16. 360 is not multiple of 16. And since 704 is fully valid, it's all good.

I think what lordsmurf was trying to say, is 704x480 is full D1 res.

720x480 is merely "DVD compliant"

[adam]

704x480/576 is NOT full D1. This resolution is referred to as cropped D1 or 1/1 D1. I've also seen this referred to as broadcast resolution.

Full D1 is defined in CCIR-601 as 720x480/576.

As others have said, half D1 is 352x480/576 so that it can be mod 16. This is also why cropped D1 is 704x480. If not rounded it would be more like 702x480/576.

[lordsmurf]

I'm still curious why 352x480 and 704x480 play fine, while 720x480 has routine errors on linear objects. I've had this commented to me by others, and I see it too.

I've seen 1/1 D1 (704) and 1/2 D1 (352) specs. I assumed that was Full and Half, but adam has clarified that a bit more.

[vhelp]

...Does anyone know why DVD is 720x480 instead of 704x480? It just seems like it should have been the same as D1.

.
.

I'm still curious why 352x480 and 704x480 play fine, while 720x480 has routine errors on linear objects. I've had this commented to me by others, and I see it too.

I've often wondered why myself. I too am curious. But, as far as the
"linear objects" thing, I think it has to do w/ the capture card in question.

* How does it handle frames.. for instance:
- - - ** 352 interpolated to 704 and resized to 720, or
- - - ** 352 interpolated to 720, or
- - - ** 704 resized to 720
or, does it depend on a "cut-off" size (ie, 352 vs. 720) or (ie, 352 vs. 704)
...and depending upon th e"cut-off" size, either it will:
- - - ** interpolate to a given size, or
- - - ** resize to a given size, or
- - - ** something entirely different all-together.

Again, as to the "linear objects", my ATI-TV Wonder will not reproduce a
given frame (pending upon size) at as smooth/sharp a Horizantal as my
Osprey-210 will. And, I think my Osprey-210 does a better job at this than
even my ADVC-100 does.. but this requires some addtional testing on.

I've also noticed that on some older THX version of VHS movies, that some
have some Horizantal issues, than todays THX version VHS movies.
.
.
Ive said in another thread, that I capture at 704 w/ my ATI-TV Wonder card,
and no boarders (though cap'ed at 720 will show boarders) and on other
cards, (ie, Osprey-210) I can capture at 720 and no boarders is evident.

So, capture cards do matter as well in this instance.

Now, I've seen many DVD's where the left/right have some boarders added
to it. I think they are usually between 4 and 8 pixels. Some examples
are:

* 8 pixels - 2.35:1 - Widescreen - Fifth Element
* 4 pixels - 2.35:1 - Widescreen - Dogma
* 8 pixels - 1.33:1 - Fullscreen - Star Trek TNG
* 0 pixels - 1.85:1 - Widescreen - Ice Age
* 0 pixels - 2.35:1 - Widescreen - KPax
* 0 pixels - 2.35:1 - Widescreen - Deep Blue Sea
* 0 pixels - 2.35:1 - Widescreen - Red Planet

So, my guess (or best theory) is that when we are dealing w/ DVD's, we
have to consider it's Aspect Ratio.. (ie, when ripping DVD's)
But, when we are talking about capturing, we are talking about an 4:3
Aspect Ratio source, and as such, we are subject to the Broadcaster's
that output a given source per Resoution and Aspect Ratio, and these
vary from Broadcaster to Broadcaster, and provider to provider, and so
on and so forth.

-vhelp 2165