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Canon VIXIA Series AVCHD and HDV Camcorders
For VIXIA / LEGRIA Series (HF G, HF S, HF and HV) consumer camcorders.


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Old November 1st, 2007, 11:58 PM   #16
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Paul:

Is this a snap taken in the still camera mode, or a frame grab, or what ? It doesn't look like it is in the right aspect ratio to be 16:9 from video.
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Old November 2nd, 2007, 12:27 AM   #17
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Originally Posted by Robert Ducon View Post
Looks like good 4:2:0 HDV 1440x1080 HDV footage to me. What do I mean? I see MPEG compression artifacts, and interlace artifacts, and that be normal. This IS an HDV consumer camera, using the commonly accepted GOP technique to capture pseudo-HD. If you notice that on HDMI input, that's good - you're seeing more detail. From what I've read, it'll all get worse with a Sony HC7 as it sharpens the image even more.

I see nothing wrong.

However, if you're not happy with a purchase, return it if that will let you feel better. Be prepared to fork out more dough for a higher end camera, or wait a year or more for a camera to offer more TVL/ph at a similar price point to still get good value on your dollar.
Sorry, but we're talking apples and oranges. I was interested in this camera because I've read that pros are using it for b-roll and 2nd unit. I didn't expect artifacts as extreme as I've found. I certainly wouldn't consider a Sony HC7 as an acceptable alternative. I'll probably wind up with an FX7 unless turning down the sharpening works.
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Old November 2nd, 2007, 12:28 AM   #18
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Originally Posted by Chris Barcellos View Post
Paul:

Is this a snap taken in the still camera mode, or a frame grab, or what ? It doesn't look like it is in the right aspect ratio to be 16:9 from video.
It's a frame grab pulled into Photoshop and saved as a jpeg.

Ooops -- just looked at it again. I may have pulled it into a Premiere Pro project with the wrong settings. I'll have to look again.

Okay, I looked --

The frame export was correct, but the pixel aspect ratio in Photoshop was wrong.
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Old November 2nd, 2007, 02:48 AM   #19
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I was considering the V1U, but the HV20's price and feature set were enough value for me. If you do get an FX7, please share your findings on this thread, and if you can visit the same location as you did with the HV20, that'd be great too.

I've shot extensively with the V1U's older brother/cousin the Z1U and, in my opinion, the Z1U can't hold it's own against the HV20 in terms of image quality/resolution/lack of noise. My personal thoughts were (before the HV20 was announced) if I were going for a larger cam, I'd have gone for the Canon XH-G1 or Sony V1U (which has a much better image processor than the Z1U). Best of luck.
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Old November 2nd, 2007, 03:13 AM   #20
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Originally Posted by Paul Tauger View Post
Sorry, but we're talking apples and oranges. I was interested in this camera because I've read that pros are using it for b-roll and 2nd unit. I didn't expect artifacts as extreme as I've found. I certainly wouldn't consider a Sony HC7 as an acceptable alternative. I'll probably wind up with an FX7 unless turning down the sharpening works.
Eh? They have inferior image to the hv20 so what exactly are you looking for? There's nothing wrong with the image you posted. Just basic mpeg-compression. And if you think a 3-ccd camcorder will take that away then think again. The V1 actually has a somewhat worse encoder than the canon cameras in terms of macroblocking. DV-cameras also encode with an mjpeg type codec so they will also feature some crawling effects on borders though not as bad as hdv. Has nothing to do with 1-ccd vs 3 or a bayer-filter.

I'm looking at that screencapture with my 24" Eizo and it looks great. Ofcourse there are compression artifacts if you zoom in 300%, it is hdv anyway.

Absolutely astonishing that an image as beautiful as this doesn't cut it for you in a consumer camera. There has to be something wrong with your Toshiba. I know that some settings in lcd-monitors can increase grain and encoding effects so atleast check your brightness levels etc.
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Old November 2nd, 2007, 10:01 AM   #21
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Originally Posted by Mikko Lopponen View Post
Eh? They have inferior image to the hv20 so what exactly are you looking for?
I don't believe the XH-A1 and the FX7 exhibit the same artifact problem.

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There's nothing wrong with the image you posted.
Then your standards are significantly lower than mine. As I said when I started this thread, high-frequency detail, literally, crawls. The artifacts exhibited in the still that I posted are not static.

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Just basic mpeg-compression.
No, it is not just basic mpeg-compression. It appears to be a combination of over-sharpening with poor mpeg-compression. I've been transcoding my standard definition video to mpeg for years to burn my own DVDs. Not one of them exhibits this kind of artifact.

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And if you think a 3-ccd camcorder will take that away then think again. The V1 actually has a somewhat worse encoder than the canon cameras in terms of macroblocking. DV-cameras also encode with an mjpeg type codec so they will also feature some crawling effects on borders though not as bad as hdv. Has nothing to do with 1-ccd vs 3 or a bayer-filter.
Sorry, but you're completely wrong. If, by "DV-cameras" you mean miniDV cameras, they use the DV-25 standard which is a non-temporal compression codec. DV-25 is not mpeg-like, because mpeg is a temporal compression codec and the typical artifacts which affect mpeg are the result of that temporal compression.

Next, Bayer-filters are used only on 1-CCD machines -- A Bayer-filter is a grid of primary color filters that allow a single sensor to reproduce colors. Obviously, there is no need for a Bayer-filter on a 3-ccd machine. Because the Bayer-filter is a grid, it can introduce high-frequency artifacts. I have an old TRV-20 that does this (if you like, I can post frame grabs that demonstrate this) and this was precisely the reason I moved to my VX2000, which is a 3-ccd machine and has virtually no perceptible artifacts.

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I'm looking at that screencapture with my 24" Eizo and it looks great. Ofcourse there are compression artifacts if you zoom in 300%, it is hdv anyway.
These are motion artifacts -- that's the problem. They are obvious and distracting without any magnification.

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Absolutely astonishing that an image as beautiful as this doesn't cut it for you in a consumer camera. There has to be something wrong with your Toshiba. I know that some settings in lcd-monitors can increase grain and encoding effects so atleast check your brightness levels etc.
There may, indeed, be a problem with my Toshiba. The fact that there are visible and obvious artifacts in a frame capture suggests otherwise. The question isn't whether the HV20 is a good for a consumer camera. It's whether it is good enough for my applications. The very limited amount of video I shot in my initial test indicates that it is not. It would be nice if it was because I wouldn't have to consider the added cost, weight and size of a prosumer machine. That is, however, exactly what I had to do to get an adequate for my purposes standard definition machine.
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Old November 2nd, 2007, 11:24 AM   #22
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I wonder if CMOS versus CCD has something to do with your complaint? I'm much less knowlegeable than you are about video, but I have read many posts about artifacts that seem to come into play on CMOS cameras that do not on CCD's. Especially when it comes to horizontal motion. It's a given to me that you absolutely must pan as slow as possible with CMOS.
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Old November 2nd, 2007, 11:31 AM   #23
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Originally Posted by John Hotze View Post
I wonder if CMOS versus CCD has something to do with your complaint? I'm much less knowlegeable than you are about video, but I have read many posts about artifacts that seem to come into play on CMOS cameras that do not on CCD's. Especially when it comes to horizontal motion. It's a given to me that you absolutely must pan as slow as possible with CMOS.
The only thing different is the rolling shutter. It seems people don't really now how to handle 24p material or have most of them even seen interlaced material.
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Old November 2nd, 2007, 11:38 AM   #24
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Originally Posted by Paul Tauger View Post
Sorry, but you're completely wrong. If, by "DV-cameras" you mean miniDV cameras, they use the DV-25 standard which is a non-temporal compression codec. DV-25 is not mpeg-like, because mpeg is a temporal compression codec and the typical artifacts which affect mpeg are the result of that temporal compression.
... Do you know what mjpeg is? It's basically a jpeg codec such as dv is. It also exhibits jpeg artifacts in images and could potentially be seen as "crawling" effect on certain types of contrasty edges. DV-codec also has artifacts that's why I mentioned it. Offcourse the artifacts will be lower, but still. They are there.

What do you mean even by "you're completely wrong". Completely wrong in what? DV-codec has basic jpeg-artifacts and they could be seen as high frequency crawling on certain edges. What is wrong in that statement may I ask?

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Because the Bayer-filter is a grid, it can introduce high-frequency artifacts. I have an old TRV-20 that does this (if you like, I can post frame grabs that demonstrate this) and this was precisely the reason I moved to my VX2000, which is a 3-ccd machine and has virtually no perceptible artifacts.
I don't buy it. If they are motion artifacts then it can't have anything to do with a bayer-filter. The RED camera also utilises a bayer filter and the results are astonishing. I'm still a believer in one ccd-machines provided the resolution and sensor size is there.

You have to be talking about mpeg-artifacts and if so an XH-A1 or the V1 will DEFINITELY not save you. They have your basic mpeg-artifacts just like in those screencaps.
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Old November 2nd, 2007, 11:44 AM   #25
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Originally Posted by Mikko Lopponen View Post
The only thing different is the rolling shutter. It seems people don't really now how to handle 24p material or have most of them even seen interlaced material.
I'm not shooting 24p. I thought I had made that clear.
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Old November 2nd, 2007, 11:49 AM   #26
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Originally Posted by Paul Tauger View Post
I'm not shooting 24p. I thought I had made that clear.
Wasn't directed at you. There so many threads where people don't know how interlacing and pulldown work even in the xl h1-forum.
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Old November 2nd, 2007, 11:54 AM   #27
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Originally Posted by Mikko Lopponen View Post
... Do you know what mjpeg is?
Yes, I do. Mpeg is not, "basically a jpeg codec such as dv." Mpeg compresses by identifying a reference frame and then compressing subsequent frames based on the delta between the reference frames and the frames that follow. DV-25 (and DV-50) only compress within in each frame. The temporal compression of mpeg is what introduces the motion artifacts. Because DV-25 does not use temporal compression, it is not susceptible to this particular form of digital artifacts.

Quote:
What do you mean even by "you're completely wrong". Completely wrong in what?
Wrong in suggesting that mpeg and DV-25/50 are the same type of compression that result in the same kind of artifacts. The lack of temporal compression in the latter is an enormous difference between the codecs.

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DV-codec has basic jpeg-artifacts and they could be seen as high frequency crawling on certain edges. What is wrong in that statement may I ask?
Nothing. However, that's not the statement that resulted in my saying you're completely wrong.

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I don't buy it. If they are motion artifacts then it can't have anything to do with a bayer-filter.
Of course it can. Bayer filters can result in "jaggies" because the grid creates a screen-door effect when resolving sharp, high contrast lines. If I get some time, I'll post some examples from my TRV20.

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The RED camera also utilises a bayer filter and the results are astonishing. I'm still a believer in one ccd-machines provided the resolution and sensor size is there.
And there are ways to address the artifacts caused by Bayer filters, both in sensor design and post-sensor processing. The RED camera isn't a consumer machine; the latter is not likely include more expensive design features that can address this.

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You have to be talking about mpeg-artifacts and if so an XH-A1 or the V1 will DEFINITELY not save you. They have your basic mpeg-artifacts just like in those screencaps.
I'm not talking about mpeg-artifacts, per se, nor has anything you've said persuaded me otherwise. However, as with the difference between my VX2000 and TRV20, I'd expect that a prosumer machine wouldn't exhibit such blatant and distracting artifacts. I haven't seen the output of an XH-A1 yet, so I can't say for certain.
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Old November 2nd, 2007, 11:55 AM   #28
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Originally Posted by Mikko Lopponen View Post
Wasn't directed at you. There so many threads where people don't know how interlacing and pulldown work even in the xl h1-forum.
Okey dokey. Sorry.
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Old November 2nd, 2007, 11:57 AM   #29
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Originally Posted by Paul Tauger View Post
Yes, I do. Mpeg is not, "basically a jpeg codec such as dv."
MJPEG (Motion JPEG), note the J in mJpeg. That is basically a dv codec. Was never comparing it straight to mpeg.

That's it, I'm gonna take some screencaptures from the HV20 and the Sony hc1 (that has the same image quality as the sony a1u) and set you straight. These cameras give an image quality that for example put the dvx100 to shame and its 3 sensors. I find it very hard to believe your vx2000 could keep up. Having seen video from vx2000 a year ago I still remember it being severely inferior to the hc1 (except in low lighting).
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Old November 2nd, 2007, 12:21 PM   #30
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Folks, if you mention Motion JPEG in a thread where MPEG is discussed, please point it out by saying "Motion JPEG" at least once... it's easy to confuse mpeg and mjpeg. And by all means, let's keep it friendly at all times, please.

By the way, single-chip RGB can be nearly as good, equal to, or even sometimes better than three-chip color accuracy depending on certain particulars... in short, single-chip RGB is in the same ball-park as three-chip.
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