MovieStuff PAL transfer question

[crimsonson]

field?

how do you define field or frame based?

DV is captured in field not frames (with 1 or 2 camera exceptions)

As you have pointed out in Adam Wilts FAQ- there is interfield compression involved.

All DV codecs (MS, Apple, Avid, Canopus, etc) I know of have a field dominant system (you need to specify it or it does for you in order to compress correctly).

the better DV codecs uses field to do FX (Avid, Canopus, etc).

Clearly DV data is captured, written and stored in fields.

Maybe I am confusing your definition with mine?

[mattias]

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor="#DDDDDD"><font size=2 face="Verdana, Helvetica, sans-serif">
"of course, the data stream written to tape still interleaves the even and odd fields for proper interlaced TV display; it's just that both fields appear to have been clocked into the transport-and-hold registers of the CCD simultaneously instead of in even-odd alternation"</font></td></tr></table></td></tr></table></BLOCKQUOTE>

he's trying to explain something completely different here, and is simplifying/generalizing a bit too much for our discussion. read the parts about the compression scheme instead.

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor="#DDDDDD"><font size=2 face="Verdana, Helvetica, sans-serif">BTW- intraframe compression only means that unlike MPEG, each frame is compressed by itself- without dependency from previous frames.</font></td></tr></table></td></tr></table></BLOCKQUOTE>

to be perfectly honest i think it's hilarious that you think that you have to explain that to me. why don't you just listen instead? some of you seem to think that i'm here to win discussions, when all i'm after is to learn things and to share my own knowledge. if somebody makes a false statement i think it's my duty to point that out. why would i claim something if i wasn't sure it was true? it's clear that you're not sure, so why don't you just go "thank you matt, now i know more than i did before" so we can move on? or if you don't understand what i mean, please tell me what isn't clear and i'll be happy to explain further.

and here's my response to your other post: http://8mm.filmshooting.com/scripts/...opic.php?t=310


/matt

[crimsonson]

Matt why dont you settle down first?

You asked a question - it was answered.

"why don't you just listen instead?"

why dont you just give counter arguments and leave the insults somewhere else.

"some of you seem to think that i'm here to win discussions"

hmmm, never said that, never implied that. In fact I asked you for further explanations.

"why would i claim something if i wasn't sure it was true?"

same here. Or such noble cause are left to person such as you?

"it's clear that you're not sure, so why don't you just go "thank you matt, now i know more than i did before" so we can move on?"

wow. I just gave you several answers...


"or if you don't understand what i mean, please tell me what isn't clear and i'll be happy to explain further."

I think I did. here let me quote myself
"Maybe I am confusing your definition with mine?"

"he's trying to explain something completely different here, and is simplifying/generalizing a bit too much for our discussion. read the parts about the compression scheme instead."

Now he's explanation is inadequate when it counters your claim but is adequate when it supports it? I dont think Adam Wilt is a buffet table.
Compression scheme instead? Yes- he says part of the DV spec is that it includes interfield compression. Or should we disregard this also since it does not support your argument.

"no, it's fixed."

I never said its not fixed - I am only saying that a field domination is necessary for proper rendering.


"so why don't you just go "thank you matt, now i know more than i did before" so we can move on?"

Sure - should I carve your statue now also?

[MovieStuff]

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor="#DDDDDD"><font size=2 face="Verdana, Helvetica, sans-serif">Originally posted by mattias:
some of you seem to think that i'm here to win discussions</font></td></tr></table></td></tr></table></BLOCKQUOTE>

And that confusion is everyone ELSE'S problem? I know you're a smart guy, Mattias, but you do sometimes come across a little combative (as do I on occasion). Perhaps our snide-remark/direct-info ratio gets a little lopsided from time to time, eh?

Roger [img]smile.gif[/img]

[crimsonson]

Roger / Blackangus

What software are you using to capture the still?

Premiere 6 has a pixel aspect ratio setting that may help resolve your problem.

Roger do some stills and send it out to some people in PAL land and see if they can work out the pixel aspect ratio. I am sure some people here have Premiere 6 as their editing tool.

[TA152]

crimsonson / Roger / Blackangus.

Just confirming that even old AP 4.0 "tweaks" any pixel format required. I even belive that the pixel format size are 1:1, at least for raw unformatted files. (editing mode).

Free pix * pix setting are available for both capture & "production".

[crimsonson]

here ya go from Mr Wilt

"of course, the data stream written to tape still interleaves the even and odd fields for proper interlaced TV display; it's just that both fields appear to have been clocked into the transport-and-hold registers of the CCD simultaneously instead of in even-odd alternation"


talking about prosumers cameras that do "frame mode" capture.

BTW- intraframe compression only means that unlike MPEG, each frame is compressed by itself- without dependency from previous frames.

[blackangus1]

Okay, I thought of a more direct way to explain the aspect ratio issue:

NTSC DV in 4:3 mode is 720x480.
NTSC DV in 16:9 mode is: ... 720x480.

All DV, all the time, is 720x480. Yet one is 1.33:1 and one is 1.78:1. Some people think there are more pixels in 16:9, but it isn't so... all DV is 720x480. There's a flag set in the data stream that tells the TV how to display the image: either using tall pixels, or using fat pixels. Either way there's the same number of pixels, but if they're interpreted to be fat & wide, then the image is stretched across a 16:9 area. But, it looks proportionally correct because the imaging device sampled and created the image using fat, wide pixels. If you displayed that same image on a 4:3 TV, it would appear to be substantially squeezed in on the sides. That's because you'd be using pixels that were intended to be displayed fat & wide but you'd be displaying them on a device that was interpreting them as tall & skinny.

If you bring a 16:9 image into your computer, it will look like it was anamorphically squoze. (squeezed?) That's because the computer uses square pixels, but the 16:9 image uses wide pixels. And that is the same reason why, if you take a 720x480 image from an NTSC source and just center it within a 720x576 PAL image, you will not get the proper aspect ratio. It will appear to be squashed down horizontally. Because PAL pixels are not the same shape as NTSC pixels.

Hopefully that makes it easier to understand...

[TA152]

Elastics by the meter / foot?

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor="#DDDDDD"><font size=2 face="Verdana, Helvetica, sans-serif">Why should I care about 16:9?
As the world slowly and painfully switches over to digital broadcasting, it looks to be a 16:9 world we're all moving into. Although it's likely to take ten years or more before 16:9 receivers outnumber 4:3 receivers worldwide, and there will always be a huge legacy of 4:3 SDTV programs in the vaults, "premium" programming in the future will almost certainly be 16:9 material, in both "standard definition" and "high definition" forms.

4:3 program material won't be obsoleted by any means, but many forward-looking producers are composing and shooting for 16:9 to maintain as high a value as possible for all future distribution possibilities. Some are actually shooting 16:9, while others are practicing "shoot and protect" in 4:3, just by making sure that the material can be cropped to 16:9 without losing any important content from the top or bottom of the image.
?

How do you get 16:9 pictures?
You can use the 16:9 switch on your camera (if it has one). Or, you can shoot and protect a 16:9 picture on 4:3. Or, you can use an anamorphic lens.

Many cameras have a 16:9 switch, which when activated results in either a "letterboxed" image and/or an anamorphically-stretched image. But beware; there's a right way and a wrong way to do this.

The "right way" is to use a 16:9 CCD. When in 4:3 mode, the camera ignores the "side panels" of the CCD, and reads a 4:3 image from the center portion of the chip. When in 16:9 mode, the entire chip is used. In either case, the same number of scanlines is used: 480 (525/59.94 DV) or 576 (625/50 DV). You can tell when a camera is capturing 16:9 the "right way" because when you throw the switch, whether the resultant image is letterboxed in the finder or squashed, a wider angle of view horizontally is shown, whereas the same vertical angle of view is present.

The "wrong way" is for the camera to simply chop off the top and bottom scanlines of the image to get the widescreen picture. When you throw the switch on these cameras, the horizontal angle of view doesn't change, but the image is cropped at the top and bottom compared to the 4:3 image (it may then be digitally stretched to fill the screen, but only 75% of the actual original scanlines are being used).

[There are some Philips switchable cameras that do clever tricks with subdivided pixels on the CCDs; when you flip into 16:9 mode, the image's angle of view will get wider horizontally and tighter vertically. So to really be sure, use the change -- or lack thereof -- in the horizontal angle of view to see if your camera is doing 16:9 "the right way".]

Some Digital8 cameras seem to split the difference: when in 16:9, the picture gets slightly cropped on top and bottom, and it gets a little wider! I don't know what's going on with the silly things; perhaps they're using some extra chip area normally used for digital image stabilization to go wider, yet they don't have a wide enough CCD for true 16:9? Puzzling... This looks like the sort of thing the Philips cameras do, but at D8's price points I seriously doubt it. Anyone with the straight dope should email me with it.

The "wrong way" is wrong because the resultant image only uses 360 lines (525/59.94) or 432 lines (625/50) of the CCD instead of the entire 480 or 576. When this is displayed anamorphically on your monitor, the camera has digitally rescaled the lines to fit the entire raster, but 1/4 of the vertical resolution has been irretrievably lost. This is not too terrible for SDTV playback (still, it isn't great), but it's asking for disaster if the image is upconverted to HDTV.

[Note that there are two "wrong ways," the vertical-pixel-shift method used by Canon and Panasonic, which isn't as bad as I make it sound; and the field-doubled/interpolated method employed by Sony (I don't know what JVC does). The Canon/Panasonic method yields images softer than true 16:9, but cleaner and sharper than the Sony method.]

The bad news is that most inexpensive DV cameras (including the VX2000 and XL-1) do 16:9 the wrong way. 16:9 chips are still very costly and the yields (and demand) are low; in late '98 Sony's DXC-D30WS 16:9-capable DSP camera (which, docked with the DSR-1 DVCAM deck, becomes the DXC-D130WS camcorder) was only available in short supply, and the Sony sales force was encouraged to steer folks to the non-widescreen D30 model unless they really needed widescreen, because the supplies were so limited. Even then, the WS model commands a US$3000 premium over its 4:3-only sibling. The Panasonic AG-D910WA, which is switchable between 4:3 and true 16:9 as well as between DVCPRO and DVCPRO50, is a good choice -- but at US$24,2000 it's not readily affordable the way a US$3,900 XL-1 is... At NAB '99 the US$15,000 DSR-500Ws single-piece DVCAM camcorder was released; it's excellent. It's the current entry-level true 16:9 camera in the DV formats. At NAB 2000 Panasonic showed the AJ-D610WA, a US$16,000 16:9 DVCPRO camcorder; JVC should be shipping the US$12,000 widescreen DV700 in 2001. </font></td></tr></table></td></tr></table></BLOCKQUOTE>

http://www.adamwilt.com/DV-FAQ-etc.html#widescreen