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Emanuel
08-14-2006, 01:59 AM
Differences between the (pseudo?) progressive scan method:


[XL1]
frame movie mode

vs.

[XL2]
"p" mode

vs.

[XL-H1 or XH-A1/G1]
"F" offer


Any thoughts?


EDIT -- BTW, also:

vs. the DVX/HVX "p" one

vs. the CineAlta's PsF

rawfa
08-14-2006, 05:12 AM
It is strange that the XL2 has a true progressive mode when they just bought the rights for true progressive. This makes you think about what have they been using so far (great job, btw). Anyway, imo, if you can't tell the difference from true progressive from fake progressive and if you don't lose resolution, then it's all the same.

Elton
08-14-2006, 09:09 AM
HDV 24F is virtual 1080 24p. (HATE the term "virtual" but it's truthful) Calling it "pseudo" or "faux" progressive negates it, IMHO.

This is only a theory, but if in this mode the image is interlaced scanned at 48i and then perfectly stitched back together to be a 24p result and you can't find any interlace artifacts, then how is it not considered progressive?

It walks and quacks like a duck, so I think it's fair to consider it of the duck species. ;-)

MovieSwede
08-14-2006, 10:10 AM
You cant perfectly make 24P out of 48i. Sure you could do stuff do get real good results (like deinteracing in post) But I dont think you will retain the full 1080 resolution.

Elton
08-14-2006, 10:41 AM
Interesting that you should say that. I've done a lot of deinterlace stuff with Magic Bullet, Nattress, etc. and I never got perfect looking progressive results. There were always a few odd repeat frames and hiccups. 24F has never EVER shown anything that looked like an interlace artifact the way software deinterlace can.

IMHO, you do get a lot closer, perceivably, to full 1080 24p resolution than the other $sub-10K cameras with Canon HDV 24F.

Emanuel
08-14-2006, 12:19 PM
IMHO, you do get a lot closer, perceivably, to full 1080 24p resolution than the other $sub-10K cameras with Canon HDV 24F.Are you saying they aren't the same thing though both @48Hz? Why?

Emanuel
08-14-2006, 12:20 PM
And if the Canon's HDV 24F/48Hz is better than the Sony's HDV 24CF/60Hz 'cause the differences, wouldn't the 25F/50Hz show the same results than the 25CF/50Hz?

Elton
08-14-2006, 12:23 PM
I've always thought the Canon 24F looked much better than CineFrame 25. CineFrame 24 is abysmal, even if there are workarounds for it.

Elton
08-14-2006, 12:24 PM
Are you saying they aren't the same thing though both @48Hz? Why?

All I'm saying is that 24F in my experience looks and feels like good 1080 24p. It's very close to CineAlta. I believe it's well worth not having to deal with 50i and converting to 25p with all the render time that would involve for good results--and even then you might have hiccup frames here and there with the software "smart deinterlace" process.

It's high res and it looks filmic. What else is there to say? End of story.

Gordon Prince
08-14-2006, 10:12 PM
The frame movie mode available within the XL1 (SD) is the same than the progressive mode of its HD version? (XLH1 and now A1/G1 as well)

Emanuel
08-14-2006, 10:54 PM
This even seems those brand FAQ :laugh: (just before your edit, Barlow) -- you know I'm a HD prosumer Canon believer.

I'd like to hear our Barry. Why has he been saying what he has pronounced about the subject?

For instance here (http://www.dvxuser.com/V6/showpost.php?p=117694&postcount=23):

The NTSC XL1 produces a "pseudo" 30P. The PAL XL1 produces "pseudo" 25P.

The NTSC XL2 produces genuine 24P and 30P, and the PAL XL2 produces genuine 25P. But the XL1 fakes it using frame mode.It was two years ago regarding the Canon SD offer. Actually he compares the Canon's XL1 progressive mode to the future CF then as fake progressive.

However, he isn't the only one [ex. in American Cinematographer (July 2003 -- 28 Days Later article) there (http://www.theasc.com/magazine/july03/sub/)]:
«(...) shot in the 4x3 aspect ratio but matted for 16x9 by the PAL XL1 (625 lines of resolution, 900,000 effective pixels over three 1/3" CCDs) in Frame Movie Mode, its pseudo-progressive-scan method, which is performed electronically within the camera»

But it's also known the Barry's comparison between the F mode and the CF one. So, if @50Hz wouldn't it be the same thing?

Then, I might purchase a Z1 when was launched...and why such HVX waiting? (How it really happened... Much ado about nothing?)
[personally speaking considering:
1) my non-HVX option;
2) and just now (almost two years later) in order to a F mode shooting ?!! -- if Barry is leaving his impression as the same stuff*??!...]

* I can figure his commitment with his favorite brand and we must discount his understandable biased POV but it's always relevant to know what he has to say.

MovieSwede
08-15-2006, 02:42 AM
Interesting that you should say that. I've done a lot of deinterlace stuff with Magic Bullet, Nattress, etc. and I never got perfect looking progressive results. There were always a few odd repeat frames and hiccups. 24F has never EVER shown anything that looked like an interlace artifact the way software deinterlace can.

IMHO, you do get a lot closer, perceivably, to full 1080 24p resolution than the other $sub-10K cameras with Canon HDV 24F.


Well thats because most people who have deinterlaced have gon from 60i to 24P.

48i to 24P should be tested against deinterlacing 50i to 25P.

The the CF25 mode is just 1080i with one line removed. If Canon used a more smart deinterlacer they would get better results.

Canon has one more benifit (as the Z1) it does the deinteraling before compression where most other deinterlacers work with already compressed material.

Of course this is just my theory, but it seems logical that they use smart deinterlacing if they capture from 48i.

Elton
08-15-2006, 07:40 AM
Canon has one more benifit (as the Z1) it does the deinteraling before compression where most other deinterlacers work with already compressed material.

Of course this is just my theory, but it seems logical that they use smart deinterlacing if they capture from 48i.

Good points. You're right, it would be interesting to compare 50i/25p conversions and 24F. I still think software will sometimes show minor deinterlacing artifacts, even from 50i.

Emanuel
08-16-2006, 12:34 AM
The frame movie mode available within the XL1 (SD) is the same than the progressive mode of its HD version? (XLH1 and now A1/G1 as well)Good question!

Elton
08-16-2006, 08:49 AM
The frame movie mode available within the XL1 (SD) is the same than the progressive mode of its HD version? (XLH1 and now A1/G1 as well)

The new frame modes are in such a different realm than the old XL1 that it's just not fair to compare. There may be some fundamental similarities in how it's achieved, but the H1's frame modes just look great in HD whereas the old XL1's mode was quite mushy compared to interlace. (in SD)

Gordon Prince
08-16-2006, 09:35 PM
There may be some fundamental similarities in how it's achievedIf we can say this on XL1/XLH1 comparision subject, will it be the same between the XL2 and its successor, the XLH1?

#If we already know being the XL2 "p" mode better than "the frame movie mode" of the XL1#

Can we closer both XL1 and XLH1 rather XL2 or not?

Elton
08-16-2006, 10:48 PM
I don't entirely understand the question. I understand the need to feel that what you're getting with a Canon is really really "progressive", but again, if you're familiar with the cadence of 24p and you take a good look at 24F stuff, nobody can honestly say they truly look different.

The way I see it is this: 24F is a different path to the same basic result.

It just works and it looks good in a 1080p frame size if shot the right way.

Gordon Prince
08-16-2006, 10:57 PM
if you're familiar with the cadence of 24p and you take a good look at 24F stuff, nobody can honestly say they truly look different.

The way I see it is this: 24F is a different path to the same basic result. Putting in another words: And already wasn't the XL1? Then, why XL2 is mentioned by Barry as true 24p and not the XL1 mode? If the XLH1 is more similar to XL1 than XL2 (if it is!... here is the question), this will be a backward step (if compared to XL2) or not?

Elton
08-16-2006, 11:16 PM
The XL2 has progressive chips, which is why it can claim "true 24p". Frame mode on the XL1 was a weird deinterlace and futzing of fields, (it was originally meant for pulling stills from video) and for NTSC users it wasn't even close to the film/24p look because it was always 30 fps.

The XL-H1 24F frame mode is doing something very 24p-like from interlace 1440x1080 1/3" HD CCD's.

I believe it's fairly obvious that the chips are clocked at the correct rate of 48 hz and somehow it's stitched together in real time as a progressive frame at 24 frames per second--and BEST OF ALL--it's recorded to tape as actual 24p that can easily be captured and exported to other codecs to work in a true 24p timeline.

Is that a step backward? Not to my way of thinking because for me, it all boils down to the core image...and I think the H1's HD image is solid to the core.

I mean, to get an image that could pass for CineAlta at less than $4K?

Pinch me. :)

Emanuel
08-17-2006, 11:00 AM
You're the Canon guru Barlow. BTW, speaking about it and following this thread, Barry PM me with his point. Regarding the same vertical resolution between F and CF modes @50Hz and a superior horizontal res as Canon's advantage -- 'cause its higher CCD res, I also add.

Bogdan
08-27-2006, 08:05 PM
Canon's 24f and 30f modes produce amazing images, hard to distinguish from true progressive scan. Since it's their closely guarded secret, we can only speculate on technicalities, but does it really matter what kind of internal processing is done inside XL-H1 and new XH line if the final quality is so close to $20k XDCAM HD?

Canon's F mode (not to confuse with Frame mode of their first XL camcorders) achieves more than 800 lines of effective resolution and at the same time images have pleasant filmic appearance. What more can we expect at this price level?

Canon's 24f, 25f and 30f images are just too good to be simply deinterlaced. The best software deinterlacers do not achieve that quality (let alone the speed) simply because it's really not easy to deal with time displacement between the fields. It does not matter if we go from 60i to 24p or 30p or from 50i to 25p. The problems are there, sometimes pretty bad, especially when we deal with fine motion of high contrast details in the image. All of that makes me think Canon phase shift signal clocking the CCDs, scanning both fields at the same time. Since the imagers are technically interlaced and the image is not captured in one sweep but with two parallel scans, the process can not be called true progressive. OK. Resolution drop in f mode vs interlaced? I think it's the result of necessary filtering applied to both scans, but if the final quality is better than anything on the market below $20k, who can seriously complain here? :)

I doubt anyone watching our movies will notice the difference between 24f and 24p, but surely people will notice the difference in resolution and overall image quality. The best resolution CCDs in the class (1440x1080) and the results Canon achieves at this price level are truly impressive.

Cheers.

Elton
08-27-2006, 08:27 PM
Excellent first post, and welcome to the forum! Canon of course won't say, but I have heard vaguely of this "phase shift signal clocking" technique, but I have no clue as to how it's done.

I think youre right about the deinterlacing thing. I've done all kinds of renders with the best algorithms and "smart deinterlacing" was never 100% perfect. By contrast, I have never seen a tell-tale deinterlace artifact from the HDV F modes.

800 lines of effective resolution? Only with 1080i, but I hate the whole resolution numbers game anyway. I've edited a fair amount of very good 24p CineAlta footage in HD, and I can say without any hesitation that the XL-H1 comes the closest to this standard.

It's not perfect, but you're right. Potentially now at an even lower price level than the H1, how can anyone complain? It's a dream for no-budget indies.

MovieSwede
08-27-2006, 11:43 PM
Its not the F mode that bothers me

its the HDV.

Emanuel
08-28-2006, 12:08 AM
Its not the F mode that bothers me

its the HDV.Buy the G1 and wait for the external HD-SDI recorder portable device option and the 10-bit Cineform RAW.

Emanuel
08-28-2006, 12:15 AM
Do you think HDV shooting means you have to EDIT in the format?Good effort Barlow. There is a lot of misunderstanding here on the subject. I didn't want to mean about MovieSwede. He knows what he's talking about. But there is who insists on that. HDV is a format like any other. With its limitations. A non-broadcasting HD format, unless as 15% or 25% of the total footage if delivered to Discovery HD channel. But with Canon you have the HD-SDI or even the uncompressed HD port. Analog in the latter case, OK but there are more than one option around the corner. I prefer it rather than the lower res HVX and its lowlight response, for example.

Bogdan
08-28-2006, 09:55 AM
I also heard a theory about phase shifting (or inverted cycle) of one of the CCDs (possibly G), but that would still result in time displacement, while Canon's images do not display any artifacts suggesting use of this technique. It's interesting. Again, it makes me think they use a kind of solution that falls in between interlaced and progressive acquisition, gathering images in two parallel sweeps, but requiring additional filtering. Anyway, I'm happy we have that quality available for big chunk less than $10k.

Some tests and camcorder comparisons available on the Web were not conducted properly. I dare to say some were quite biased against Canon XL-H1. When 24f or 30f footage is imported properly (e.g. with Premiere Pro and Aspect HD), I can clearly see vertical resolution of 800 lines, but what matters more is it behaves very nicely in fine motion. In currently commercially available technology, only Cinealta provides better results.

I am convinced Canon's HDV compression in F mode uses progressive scans which is much more efficient than interlaced compression (and that's why it can not be played back on other HDV equipment). At 25mbps rate, it produces really impressive results with minimal motion artifacts. For many of us it's a dream come true, even without HD SDI option.

MovieSwede
08-28-2006, 10:24 AM
Is it just me or could pixelshift be invovled in the process?

Bogdan
08-28-2006, 11:37 AM
Pixel shift is standard on most cameras today, including H1 and it works in both interlaced and progressive modes. I don't think it's related to f mode specifically. Shifting CCD horizontally or in both directions will not eliminate problems associated with interlaced scan. Imho Canon did not go this way. Seems way too hard to produce such nice progressive look real time in the camera, even with advanced processor.

Elton
08-28-2006, 01:18 PM
As a matter of fact, the XL-H1 pixel shifts horizontally to achieve full-raster SDI spec. The CCD's pixels have a wide aspect ratio of 1.212...if you multiply 1440 x 1.212 you get 1745 horizontal res, which is then pixel shifted to achieve 1920.

Elton
08-28-2006, 01:42 PM
I am convinced Canon's HDV compression in F mode uses progressive scans which is much more efficient than interlaced compression (and that's why it can not be played back on other HDV equipment). At 25mbps rate, it produces really impressive results with minimal motion artifacts. For many of us it's a dream come true, even without HD SDI option.

You're correct. The camera's MPEG2 encoder is fed a progressive image in F mode, which generally compresses better and is more artifact resistant than regular 1080i mode. I also believe it has a shorter GOP cycle in 24F, but I'm not absolutely certain.

Bogdan
08-28-2006, 02:12 PM
You're correct. The camera's MPEG2 encoder is fed a progressive image in F mode, which generally compresses better and is more artifact resistant than regular 1080i mode. I also believe it has a shorter GOP cycle in 24F, but I'm not absolutely certain.

Shorter GOP in 24F makes perfect sense with extra 20% bandwidth available compared to 30F.

Elton
08-28-2006, 02:21 PM
A non-broadcasting HD format, unless as 15% or 25% of the total footage if delivered to Discovery HD channel.

Wanna know something funny? I just recorded a Discovery HD program last night called "Iconoclasts" which was originally produced for the Sundance Channel.

I swear it was all Sony HDV. I know the look well, and it was unmistakeably Z1u. It looked like it was shot CineFrame 30. A tiny bit soft for HD, but still decent...although you could definitely see a difference between the preceding program shot mostly on Varicam and CineAlta (it was called "Discovery Atlas") and the Z1.

You know what though? The show was about Robert Redford , Paul Newman, and their history together...and guess what? Content trumped technical specs, and it probably didn't hurt that the show featured lots of footage of both famous actors hanging out and waxing philosophical about their movie experiences.

Discovery HD will apparently bend the rules for acquisition as long as it features famous people or the content is very compelling.

Zim
08-28-2006, 03:35 PM
they probably need HD footage too.