720x480 vs. 856x480

[Brad Simmons]

yes, it has an analog breakout box as well.

[Julian Luttrell]

Brad,

is your comp accidentally set to square pixels? This would have the effect of making it look right at 856x480...

Julian

[Simon Orange]

Ok....

I assume that what canopus have done is to fudge the way that it deals with widescreen footage to make it compatible with with the analog section of the card (?) - This would mean that the analog section would dispay 16:9 FHA correctly...out of interest what is the frame size of the normal (not widescreen) NTSC DV storm premiere preset ?

If this is the case..and canopus insists on capturing the footage at this frame size you should use the same frame size in AFX (don't do the interpret aspect ratio on the clip) and just work with it whilst viewing your clips 'squashed' (although I think that 856x480 is about right for 16x9). I know this is a pain...you have to do this with flame* which costs considerably more than AFX !

AFX only understands a couple of different pixel aspect ratios.

simon

[Brad Simmons]

Julian <<<-- Originally posted by Julian Luttrell : Brad,

is your comp accidentally set to square pixels? This would have the effect of making it look right at 856x480...

Julian -->>>
---------------------------------------------------------

Hi Julian. No, my comp has a preset of NTSC DV Widescreen, and the pixel aspect ratio is the same thing - NTSC Widescreen (1.2)
And my footage is interpreted as widescreen as well.

Simon, I see what you're saying.
Basically in AFX if I create a comp with 856x480 frame size, it will look perfect in AFX, as shown in this shot http://www.fusionarena.com/forumpost/megwide.gif

So what I'm saying is, it doesn't look squashed at all in this mode. It only looks squashed when I set the comp to 720x480. So actually this works better for me I think, because I'll be able to work on the clips as they were meant to be seen. Problem is I have no idea how 856 wide could be the real size, since everyone here is saying widescreen is 720 pixels wide?

As for your question, the frame size of the normal DV Storm preset is 720x480.

I think I am losing my head over this. I've learned a lot from this thread though, sorry for being so confusing, if only I could talk to someone about this it'd be so much easier. thanks for all the responses guys.

[Simon Orange]

The problems you are having are because the Storm card is using non-standard framesizes...for reasons we can only guess at.

The AFX widescreen setting is based on normal-standard-everyday DV widescreen 16:9 FHA settings, which it seems canopus (in their wisdom) have deviated from. This means in your case the AFX preset is useless.

Your aim in this is not to have to re-size footage, this would mean some kind of interpolation of the footage and therefore quality loss. DO NOT INTERPRET FOOTAGE AS WIDESCREEN then you won't have to resize.

Set up your own AFX preset based on the canopus premiere capture settings and all should be well - a couple of seconds with a calculator shows that frame sizes will display fine in AFX without using any kind of pixel aspect ratio compensation. When you import the footage you should not have to do any rescaling, it should just snap fine into the comp frame.

The next issue you will hit is how to render the stuff out...I assume that canopus provide a codec which renders out the stuff with the same frame size ? If you need any pointers let us know.

simon

[Brad Simmons]

Thank you Simon. That is exactly what I needed to know! I just need to make a different comp size as a preset. It really does make more sense to me now, and yes, Canopus does have a codec I can render it out to and import back into Premire if need be. The goal is to get this thing viewed normally on a widescreen TV, but also make a regular NTSC television version - letterboxed.

Basically you're saying, as long as I'm not physically resizing the video, I should be fine, and I believe your right. I worked with the 856 comp setting in AE and then exported it back out to Premiere. It displayed normally again in the widescreen mode. For the standard television version, all I have to do is import that widescreen version into a 4:3 project setting, apply a verticle transform and it automatically places letterboxes on the top and bottom. Looks great!

btw, if I scale down widescreen footage in normal 4:3 mode, I've heard people say to use 75 percent scaling in order to get the letterboxes. It looks fine, but I was just wondering if that is mathematically verified? Is it really exaclty 75 percent or is it 77 etc?

Thanks again for the help.

[Simon Orange]

it is exactly 75%...get out the calculator:

difference between 16:9 and 12:9 (4:3) is 75% on vertical axis.

One last thing, if you are gonna broadcast the piece and want to do a 4:3 letterbox version, my advice is to do the whole project 16:9 and let the broacaster run it through its ARC (aspect ratio convertor) - or at least speak to the broadcaster to see what format it needs.


si

[Rob Lohman]

According to a Pixel Aspect of 1.2 for NTSC Widescreen your
footage should be 864 wide, not 856. Oh well, it is all in numbers.

But, as someone else stated (and his is correct) the footage is
still 720x480 on tape/in your AVI. What has change is the Pixel
Aspect ratio. This is the ratio for width vs. height. Normally an
NTSC pixel is 90% of the width as its height. In widescreen is
has a ratio of 1.2 and is therefor 120% the width as its height.
What the programs are doing (since you are VIEWING the
material on a square pixel monitor [1.0]) is RESIZING/RESAMPLING
the footage to the 1.0 aspect ratio (which in the case of your
widescreen footage means resizing the width by 1.2 times)
for VIEWING. They also give you the resolution probably so you
can interpret it better or for communication with other applications.

I hope this explains it a little bit better!

[Simon Orange]

Rob....the whole point is - using the canopus setting the AVI footage ISN'T 720x480

addtionally I make it that the horizontal frame size is 480/9 * 16 = 853.3333 not 856 (or 864) but near enough !

if you follow the thread we are suggesting that canopus are using square pixels not rectangular - either to maintain compatiblity with the anolog section of the storm card of for some other reason we cannot understand.

si

[Brad Simmons]

Yes, based on the info here I think I finally understand what to do. I have to do this all differently because damn Canopus captures this in square pixels, (who knows why).

I must interpret that footage as square pixels if I'm using the original 856x480 captured footage in After Effects.

1. If I capture the widescreen footage in Premiere, THEN export from Premiere at widescreen 720x480, then I can use the 720x480 widescreen default comp in After Effects - as long as I change the pixel aspect ratio for the footage to widescreen.

2. I still can use the 720x480 widescreen comp in After Effects IF I am using the original 856x480 footage (not exported as 720x480 from Premiere), as long as I make sure that the footage is interpreted as square pixels in After Effects.

3. Finally, I can create a 856x480 composition, and use the original captured footage, if I interpret that footage as widescreen.

All of these three methods seem to produce the same exact results from my naked eye.


The way Canopus handles this really confused me. I think I was also getting frame aspect ratio and pixel aspect ratio confused. Hopefully this thread will help those who have a Canopus and want to capture widescreen. Thanks for the info all, if you have anything more to add please do.

[Boyd Ostroff]

<<<-- Originally posted by Brad Simmons :Boyd, when choosing between 16:9 or 4:3 on a camera such as the XL1s, isn't the resolution the exact same? In one method you're cropping in post, the other method crops in camera, and you shrink it down to play on NTSC. Both seem to end up doing the exact same thing in the long run don't they? -->>>

I think there are two issues:

1. True, on the XL-1s the 16:9 mode involves cropping down your regular 4:3 image, then stretching so it becomes anamorphic. However there's some discussion of the fine points of the process as it relates to DV compression, and evidently the results vary between different models of camera. See Adam Wilt's website for more info http://www.adamwilt.com/DV-FAQ-etc.html#widescreen

2. What do you plan to use the footage for? Do you just want to letterbox it for 4:3, or do you want to view it on a widescreen TV? For letterboxing either method should work equally well. However if you need anamorphic 16:9 and you've shot 4:3, then you'll need to crop and then stretch it vertically in post to get the correct aspect ratio.

Personally I like Simon's suggestion to keep it anamorphic and let the broadcaster letterbox as needed. That way if you're doing titles or effects they will take advantage of the full 480 vertical lines.

[Brad Simmons]

2. What do you plan to use the footage for? Do you just want to letterbox it for 4:3, or do you want to view it on a widescreen TV? For letterboxing either method should work equally well. However if you need anamorphic 16:9 and you've shot 4:3, then you'll need to crop and then stretch it vertically in post to get the correct aspect ratio.

------------------------------------------

Boyd,
Ideally I'd like both! :) I'd like for this film to be seen on both widescreen television as well as letterboxed for 4:3 so I can put it on DVD and VHS and people will be able to see in on tv.

I guess widescreen television is not that important, but if this film is good enough I want to send it to some film fests. Do thy only show widescreen? What do they usually use? Would it look bad projected in a theater if shown on widescreen?

[Simon Orange]

more or less right I think.

to clarify again (!!!!) hopefully


It seems that you footage captured in premiere 'IS' square pixel (846x480)....so your first point is absolutely correct - and 'IS' the way you should work.

and your remaining points........

1. If I capture etc etc...

Yes correct...but beware you could potentially suffer a quality loss doing this (scaling down from 846 to 720 horizontally).

2. I still can use the 720 etc etc......


No...you shouldn't do this !.... If the footage is 856x480 square pixel it is just that: 856x480 square pixel.....NOT 720x480 horizontal pixel - therefore project should reflect this....
If you use this setting and import the footage as 720 widescreen pixels (in AFX speak) then AFX will scale the footage to fix your comp (loosing a 136 pixels en-route and draging these remaining pixels out to look like 856 pixels - as in 1. above) ...are you with me so far.... then when you render back out with the canopus DV AFX will scale the footage back up from 720 widescreen pixels back to 856 square pixels to import back into premiere.(more quality lost)..phew !


3. Finally, I can etc etc etc.

Yes..and No ! Create the composition in AFX at 856x480 but you don't need to use widescreen pixel aspect ratio and don't interpret the footage as such (cause it ain't !). You might end up with the same kind of interpolation errors as mentioned in 2.

The widescreen setting in AFX are only for anamorphic (vertically stretched) footage ONLY. As a general rule you want to do as little scaling-resizing as possible. Try and work in the natural frame size as your footage. Additionally try to do as few renders as possible - every time you recompress your footage you loose qualtity....indeed the first recompress usually gives the biggest quality drop (for the pedantic take a look at
http://home.insightbb.com/~george/codec/Intro.html for some real world examples)

As regards Boyds point....and I suspect Boyd and I are in agreement on this (?) - shoot 16:9 full height anamorphic and do all your work in this format. But as Boyd mentions it depends on what you are going to do with the footage. If it is for broadcasters they will prefer 16:9 FHA. The ARCs that most broacasters have will do a better job of doing the letterboxing than doing it in AFX and exporting to a DV tape.........Before anybody jumps down my throat on that point I think that it is obvious that footage that has been decompress-cropped-compressed onto a lossy format will suffer more artifacts than a nice quality ARC.


Just read your reply......shoot (preferably with a lens adapter) full height anamorphic if you wanna go to film ....you need as much resolution as you can. (I know you'll get as many opinions on this as there are people on this board).

simon

[Brad Simmons]

Hi Simon,

Ok I'm following you.
When at first I did those tests, it all looked fine. Now I can see where some of those methods would lead to quality loss. I looked at some posts and they have confirmed the Canopus DV widescreen NTSC codec is a frame size of 856 X 480. This is almost exactly 16 X 9 and square pixels. For whatever reason, perhaps some sort of limitation in the implementation of their effects and transitions, Canopus chose to
provide widescreen support by setting up projects as 856x480 with square pixels instead of 720x480 with the correct pixel size.

I've tried to change the capture settings so that it won't capture in square pixels, but it seems dead set.

So, what would you suggest the best method of working in After Effects should be? From you post, I gathered two methods you seemed would work. Create the composition in AFX at 856x480 (square pixel comp, square pixel footage right?) and just work on comps at that setting, OR export my captured 856x480 file out of Premiere at 720x480 (which may result in quality loss?
I knew initially that creating a comp size in AFX at 856x480 would work, but I didn't know if it was "enlarging" the video to a larger size, thus destroying the quality.

Thanks for all your help here.

[Simon Orange]

Brad,

I think you're probably correct about the reasons behind canopus' odd frame size............

Firstly if the canopus DV codec captures at 856x480 square pixels then work in that format. As you have found, you will have to use that setting in premiere to capture correctly.

Once captured in this frame size, any deviation will more than likely involve some kind of quality loss. This means that AFX project should be set at 856x480 square pixels. Note that this is most definitley not the same as 720x480 'widescreen' pixels - even if they may look the same. Exporting out of premiere at 720x480 will work but you will suffer two sets of quality loss (you lose data making frame smaller to export from premiere and lose quality making frame larger when you pull it back in to premiere.) I don't think this contradicts anything I said earlier (the answer to point 1 previously).

Forgive me if I am making this more complicated than it need be (I could just tell you to work in AFX at 856x480), but it seems more sensible to try to explain the reasons why...then you will understand the ramifications of changing frame sizes etc etc.

In the spirit of that, and in an attempt to maintain maximum quality (v. important with DV footage - especially if you are thinking of going to film)......one further thing that I touched on earlier:

Ideally when you export from premiere it will not need any re-rendering at all...therefore in AFX you are using first generation copy. The issue comes when trying to export from AFX.... I assume that the canopus codec is available when you try to make and avi in 'make movie' - this should keep the frame size at 856x480. This is the correct codec to use and means that when you pull the footage back into premiere, premiere will show the footage as not needing rendering (no red bar above footage)... This would ensure best quality.

The aim is to only ever have one lossy (DV) render...the one you do exporting from AFX. You could export as an uncompressed image sequence but you will still end up having to render this if you pull back into premiere so it's swings-and-roundabouts. If you really are going to transfer to film and the AFX work is the last thing you do...after the edit...you might be best exporting as image sequence then there is NO lossy render at all - give them the uncompressed sequence. In our online suites we get loads of footage as uncompressed image sequences...it is the format of choice for 3D work.

The only problem I can see with any of this is if you want to exchange AVI files with anybody else using standard frame sizes....it will work but you will not have optimum quality (for reasons outlined above). Shouldn't be an issue if you are just doing the editing/compositing on your machine.

If of this makes no sense then let me know.

simon