frame mode at DVinfo.net

Alex Harding · November 18th, 2004, 08:02 PM

what is the diference between 24p and frame mode on an XL1 / XL1s?

Are there any drawbacks with frame mode?
thanks,
alex

Jimmy McKenzie · November 18th, 2004, 08:22 PM

Huge difference. Half your resolution is tossed when in frame mode. The new XL2 in progressive is full frame. You will need light for scenes of low contrast where you could pull it off before in 60i.

Alex Harding · November 18th, 2004, 09:38 PM

thanks,
im still struggling a bit here though. i can understand why shooting de-interlaced would half the resolution, though i'm still unclear as to the specific advantage in such high resolution ccd's in a camera that records at 720 x 576.
cheers,
alex

Don Palomaki · November 19th, 2004, 05:31 AM

Frame mode on the XL1/XL1s uses green pixels from one field and red/blue pixels from the othe field to form the frame, a vertical pixel shift as it were. It removes inter-field motion effects, similar to progressive scan, but does result in some loss of vertical resolution because you are not using a full sampling of each line in each field.

Also 24P is 24 frames per second, with NTSC frame mode is 30 frames per second, so you will see the frame rate effect differences in moving objects and pans/tilts.

Nominally the vertical resolution of a normal interlaced NTSC image is 480 lines, simple field doubling would give 240 lines, and frame mode nets on the order of 360 lines.

Whether or not the visual effect is huge will depend on subject matter and viewing system. And of course which looks better is in the eye of the beholder.

Mathieu Ghekiere · November 20th, 2004, 12:45 PM

it's not the half of your resolution that you loose. It's only 25 % of the vertical resolution (or horizontal, one of both).
That's what I read though.

Rob Lohman · November 22nd, 2004, 06:59 AM

<<<-- Originally posted by Jimmy McKenzie : Huge difference. Half your resolution is tossed when in frame mode. -->>>

That is not true, neither of the frame mode or the de-interlacing
on computers these days. The exact loss is not known (also
because it depends on the footage you shot etc.) but it certainly
is lower than half.

Alex Harding · November 22nd, 2004, 07:04 AM

so, aside from the fact that frame mode is a diferent frame rate (actually 25 for me since i'm using PAL), and since the resolution difference is an issue but more negligable than first thought, what is so much better about 24p?

Jimmy McKenzie · November 22nd, 2004, 07:07 AM

Hi Rob,

Perhaps you can clarify.

My understanding is that the resolution is dropped due to the interpolation or duplication compression of the mystery green pixel resulting in the poorer colour set.

You mentioned that this is not true, but that the resolution loss is around 50% less.

Curious.

Jimmy.

Rob Lohman · November 22nd, 2004, 07:22 AM

I can't technically explain to you what happens since I don't know
exactly. There was an excellent page back in the days that
described it, but I don't know where it is at or if it still exists
today. It is just a known that it is less than 50%. I'll try to refind
the paper.

Edit: it looks like the paper was from Adam Wilt and it is not
currently avaible on the web...

Leonard King · November 23rd, 2004, 02:18 AM

So what you're tryng to say is that if you shoot using Frame Mode in conjunction with 16:9 the pictures will move from being awful to TRULY awful?

I don't mean to sound like I'm flaming, especially on my first post. I've only recently purchased an XL1S and immediately took it into work to see the results on prefessional monitors. I probably didn't shoot enough footage to do a good job of it, but I didn't see much resolution difference between the frame mode and standard, at least nowhere near as much of a resolution drop as there was between 4:3 and 16:9.

Don Palomaki · November 23rd, 2004, 05:37 AM

Frame mode composes a full frame image based on the data read from green pixels on one field and the red & blue pixels in the other field at the same time, so ther is no inter-field motion blurr. This gives it a progressive-like look. Because the image is updated every 1/30 (1/25 for pal) it tends to have a more film-look for motion than standard video.

Because image is formed from data sample from every line in the image it can have higher resolution than an image based on a single field. However, the exact resolution will depend somewhat on the content of the image, especially the mix of colors and their purity present in the image. I believe the resolution will be lower for objects containing single pure primary colors, and higher for objects with a blending of primary colors.

On the average, it tends to fall halfway between 480 and 240 lines.

Jimmy McKenzie · November 23rd, 2004, 06:58 AM

Thanks Don. So that being the case, the difference when moving up to the XL2 is at a completely different plane. Full RGB colour space on progressive captured frames?

Jiggy Gaton · November 23rd, 2004, 07:14 AM

wow u guys lost me here! i have read that frame mode (sometimes mentioned as movie mode) can be used to give XLS1 footage a more movie-like look. I have a PAL and was hoping to do exactally this. (softer look). Am i on the right track? thanks!!!
jigs

Rob Lohman · November 23rd, 2004, 07:19 AM

Leonard: it is known that there is a massive drop of resolution
in 16:9 mode because it is no true 16:9. Every other camera
that is not true 16:9 (most of them) has this, with exceptions
like the new XL2 (true 16:9).

Normally the picture is 720 x 480 pixels in 4:3. However, in these
faux 16:9 modes the picture is cropped to around 720 x 364 and
then stretched back to 720 x 480. So you loose 116 pixel rows
or almost 25% (probably even more since it also needs to stretch
the picture up).

If you care about the resolution you will be better off with an XL2
with native 16x9 and true progressive. Or you can get an
anamorphic attachment for the XL1S.

Personally I always just cropped the information and work with
the loss. The camera still produces incredible images in my mind,
resolution isn't everything either (people are currently "complaining"
about moire patterns with the XL2 due to the fact it is very sharp
with a much higher resolution).

Jimmy: that is correct!

Jiggy: yes it can certainly help. But as I have "preached" before,
there is much more to a "film look" than simple settings. The
primary things being:

- story (script)
- acting (actors)
- framing (and thus camera support gear)
- lighting
- editing
- audio recording + music

etc. etc. it all works together!

Leonard King · November 23rd, 2004, 07:23 AM

I did have a play on the XL2 and considered it, however the cost kind of left me behind. I was only able to convince the wife to let me have the money for the XL1S because it was on serious special.

I knew about the 16:9 issues going in, so that's not such a big problem. I can always find a way around it. However I'm glad I now have a better idea of what's going on in Frame Mode. That will be very handy down the track.

November 18th, 2004, 08:02 PM	#1
Alex Harding New Boot Join Date: Aug 2004 Location: london / bournemouth Posts: 22	frame mode what is the diference between 24p and frame mode on an XL1 / XL1s? Are there any drawbacks with frame mode? thanks, alex

November 19th, 2004, 05:31 AM	#4
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	Frame mode on the XL1/XL1s uses green pixels from one field and red/blue pixels from the othe field to form the frame, a vertical pixel shift as it were. It removes inter-field motion effects, similar to progressive scan, but does result in some loss of vertical resolution because you are not using a full sampling of each line in each field. Also 24P is 24 frames per second, with NTSC frame mode is 30 frames per second, so you will see the frame rate effect differences in moving objects and pans/tilts. Nominally the vertical resolution of a normal interlaced NTSC image is 480 lines, simple field doubling would give 240 lines, and frame mode nets on the order of 360 lines. Whether or not the visual effect is huge will depend on subject matter and viewing system. And of course which looks better is in the eye of the beholder. __________________ dpalomaki@dspalomaki.com

November 22nd, 2004, 06:59 AM	#6
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	<<<-- Originally posted by Jimmy McKenzie : Huge difference. Half your resolution is tossed when in frame mode. -->>> That is not true, neither of the frame mode or the de-interlacing on computers these days. The exact loss is not known (also because it depends on the footage you shot etc.) but it certainly is lower than half. __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

November 22nd, 2004, 07:04 AM	#7
Alex Harding New Boot Join Date: Aug 2004 Location: london / bournemouth Posts: 22	so... so, aside from the fact that frame mode is a diferent frame rate (actually 25 for me since i'm using PAL), and since the resolution difference is an issue but more negligable than first thought, what is so much better about 24p?

November 22nd, 2004, 07:22 AM	#9
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	I can't technically explain to you what happens since I don't know exactly. There was an excellent page back in the days that described it, but I don't know where it is at or if it still exists today. It is just a known that it is less than 50%. I'll try to refind the paper. Edit: it looks like the paper was from Adam Wilt and it is not currently avaible on the web... __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

November 18th, 2004, 08:22 PM	#2
Jimmy McKenzie Major Player Join Date: Jan 2004 Location: Waterloo Ontario Posts: 721	Huge difference. Half your resolution is tossed when in frame mode. The new XL2 in progressive is full frame. You will need light for scenes of low contrast where you could pull it off before in 60i.

November 18th, 2004, 09:38 PM	#3
Alex Harding New Boot Join Date: Aug 2004 Location: london / bournemouth Posts: 22	thanks, im still struggling a bit here though. i can understand why shooting de-interlaced would half the resolution, though i'm still unclear as to the specific advantage in such high resolution ccd's in a camera that records at 720 x 576. cheers, alex

November 20th, 2004, 12:45 PM	#5
Mathieu Ghekiere Inner Circle Join Date: Jun 2004 Location: Belgium Posts: 2,195	it's not the half of your resolution that you loose. It's only 25 % of the vertical resolution (or horizontal, one of both). That's what I read though.

November 22nd, 2004, 07:07 AM	#8
Jimmy McKenzie Major Player Join Date: Jan 2004 Location: Waterloo Ontario Posts: 721	Hi Rob, Perhaps you can clarify. My understanding is that the resolution is dropped due to the interpolation or duplication compression of the mystery green pixel resulting in the poorer colour set. You mentioned that this is not true, but that the resolution loss is around 50% less. Curious. Jimmy.

November 23rd, 2004, 02:18 AM	#10
Leonard King Tourist Join Date: Nov 2004 Location: Brisbane, QLD, Australia Posts: 2	So what you're tryng to say is that if you shoot using Frame Mode in conjunction with 16:9 the pictures will move from being awful to TRULY awful? I don't mean to sound like I'm flaming, especially on my first post. I've only recently purchased an XL1S and immediately took it into work to see the results on prefessional monitors. I probably didn't shoot enough footage to do a good job of it, but I didn't see much resolution difference between the frame mode and standard, at least nowhere near as much of a resolution drop as there was between 4:3 and 16:9.

November 23rd, 2004, 05:37 AM	#11
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,488	Frame mode composes a full frame image based on the data read from green pixels on one field and the red & blue pixels in the other field at the same time, so ther is no inter-field motion blurr. This gives it a progressive-like look. Because the image is updated every 1/30 (1/25 for pal) it tends to have a more film-look for motion than standard video. Because image is formed from data sample from every line in the image it can have higher resolution than an image based on a single field. However, the exact resolution will depend somewhat on the content of the image, especially the mix of colors and their purity present in the image. I believe the resolution will be lower for objects containing single pure primary colors, and higher for objects with a blending of primary colors. On the average, it tends to fall halfway between 480 and 240 lines. __________________ dpalomaki@dspalomaki.com

November 23rd, 2004, 06:58 AM	#12
Jimmy McKenzie Major Player Join Date: Jan 2004 Location: Waterloo Ontario Posts: 721	Thanks Don. So that being the case, the difference when moving up to the XL2 is at a completely different plane. Full RGB colour space on progressive captured frames?

November 23rd, 2004, 07:14 AM	#13
Jiggy Gaton Regular Crew Join Date: Sep 2004 Location: kathmandu, nepal, no kidding! Posts: 62	wow u guys lost me here! i have read that frame mode (sometimes mentioned as movie mode) can be used to give XLS1 footage a more movie-like look. I have a PAL and was hoping to do exactally this. (softer look). Am i on the right track? thanks!!! jigs __________________ For more Adventures of Herojig, see www.extreme-nepal.com or go read the NEPALI TIMES every Friday.

November 23rd, 2004, 07:19 AM	#14
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	Leonard: it is known that there is a massive drop of resolution in 16:9 mode because it is no true 16:9. Every other camera that is not true 16:9 (most of them) has this, with exceptions like the new XL2 (true 16:9). Normally the picture is 720 x 480 pixels in 4:3. However, in these faux 16:9 modes the picture is cropped to around 720 x 364 and then stretched back to 720 x 480. So you loose 116 pixel rows or almost 25% (probably even more since it also needs to stretch the picture up). If you care about the resolution you will be better off with an XL2 with native 16x9 and true progressive. Or you can get an anamorphic attachment for the XL1S. Personally I always just cropped the information and work with the loss. The camera still produces incredible images in my mind, resolution isn't everything either (people are currently "complaining" about moire patterns with the XL2 due to the fact it is very sharp with a much higher resolution). Jimmy: that is correct! Jiggy: yes it can certainly help. But as I have "preached" before, there is much more to a "film look" than simple settings. The primary things being: - story (script) - acting (actors) - framing (and thus camera support gear) - lighting - editing - audio recording + music etc. etc. it all works together! __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

November 23rd, 2004, 07:23 AM	#15
Leonard King Tourist Join Date: Nov 2004 Location: Brisbane, QLD, Australia Posts: 2	I did have a play on the XL2 and considered it, however the cost kind of left me behind. I was only able to convince the wife to let me have the money for the XL1S because it was on serious special. I knew about the 16:9 issues going in, so that's not such a big problem. I can always find a way around it. However I'm glad I now have a better idea of what's going on in Frame Mode. That will be very handy down the track.