Aspect ratio settings in MPEG Streamclip

[Shane Ross]

[Bobby Hall] “Is it wise to put 854×480 footage in a 1920×1080 timeline in FCP 7?”

Sure. It’s 16:9. You will have to scale it up and render, but that’s it.

[Bobby Hall] “And could you also create an 854×480 sequence in FCP 7?
“

No. That’s non-standard frame size, and FCP 7 doesn’t like non-standard. SD was always 4:3, and the footage was letterboxed, or anamorphically squeezed, to accommodate that. You have extracted and un-anamorphically squeezed it…which is fine for what you are doing.

Shane
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[Bobby Hall]

Thanks for the info!

[Bobby Hall]

When I open up one of the DVDs in MPEG Streamclip and click “show stream info” it says it’s 720×480 and when I choose to convert it to .mov it defaults at 640×480. I converted it to this aspect ratio as well as 720×480 to see the difference and they both look exactly the same. Why is this?

[Bobby Hall]

Aren’t all DVDs 720×480? Why shouldn’t I choose 720 when ripping from a 4:3 DVD?

[Bobby Hall]

Dave (or anyone else),
I did as you suggested and ripped a portion of my 16:9 SD DVD and chose 720×480. Of course it looks squeezed in Quicktime and Final cut Pro 7 unless I check “anamorphic” in the sequence settings. I also converted the clip at 854×480 to compare them both in FCP 7.

The 720×480 clip is just slightly horizontally more stretched than the 854×480 clip but the 720 one also shows just a little bit more detail on the sides. But the 854×480 clip seems more correct to me because of the slightly stretched picture on the 720 one. Does this have anything to do with square vs non-square pixels? I’m trying to understand this!

Also, the 16:9 DVD footage is going in a 1920×1080 sequence, and dropping the 854×480 clip looks better than putting the 720×480 clip in because then I have to distort the aspect ratio of that clip and change the scaling. So in this circumstance, isn’t it better to convert the 16:9 SD footage as 854×480? You said ripping at 720×480 yields better resolution, so I don’t understand! Thanks for any help!

[Bobby Hall]

Ok, thanks Dave. I’m trying to better understand aspect ratios of DVDs and how they’re displayed. I’ve read that all DVDs, whether 4:3 or 16:9, are 720×480 pixels.

If you have a fullframe pan & scan DVD and display it in its native 1.5:1 dimensions, how would this look? Does it look horizontally stretched? And is showing it in 4:3 just a matter of squishing it horizontally until it’s 4:3?

And if you have a 4:3 letterboxed DVD, does it do the same thing as above and the only difference is black bars are encoded in the top and bottom of the frame?

If you have a 16:9 Anamorphic DVD, which is also 720×480 pixels, how does it look if displayed in its native 1.5:1 ratio? I don’t quite understand this and I’m just curious how it would look compared to a 4:3 DVD.

Also, since pixels on a DVD are rectangular, I don’t understand how the 720×480 ratio is 1.5:1. To me this only makes sense if the pixels are square because then the width and height would be the same.

If the width of a pixel is longer than its height, you can’t divide them to get the aspect ratio, right? For instance, if you had a frame of 15 pixels wide and 10 pixels high, and if the pixels are 2 inches wide and 1 inch high (for the sake of argument), then the width of the frame would be 30 inches (15 pixels times 2 inches) and the height would be 10 inches (10 pixels times 1 inch). This would give an aspect ratio of 3:1. It would only be 1.5: 1 if the pixels were square. So how does a 720×480 DVD with rectangular pixels come out to 1.5:1?

[Bobby Hall]

Also, when I rip DVD files to convert to .mov for editing in FCP 7, should I choose 720×480 unscaled or DV NTSC? What’s the difference?

Should I deinterlace or not? Does mixing this footage with progressive footage have any influence on whether or not you choose to deinterlace?