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Canon's Secret to Achieving High Resolution in 1080p
Canon XL H1 Resolution from Shannon's chart: 800Hx650V progressive http://www.cinemahill.com/hidef/xlh1...s/IMG_0115.jpg
800Hx800V interlaced is from a reputable German magazine How is Canon able to achieve such high resolution in progressive compared to interlaced resolution? The chips are most likely using a pixel shift so the initial derived resolution that Canon starts with is higher than 1440x1080. The 1080p stream is derived from this higher resolution interlaced stream. The conversion to progressive seem to happen at the uncompressed level, because the uncompressed HDSDI, as far as I remember, includes 1080p output. I think that Sony Z1 uncompressed output is interlaced only, which means that deinterlacing is most likely done in the MPEG2 encoder. That means that Sony starts with 1080i signal wheras Canon is likely to start with significantly higher resolution when deinterlacing. Progressive LCD images on Z1 LCD may be simulation only, e.g. skipping one field. |
Hey Petr, have you seen any low light footage beside Kakus of the XL H1? I wouldn't mind pickin up an H1 to go along with my HVX if the difference is noticeable enough. =)
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The camera is about 800 lines in 24F mode. It's amazing how that obscure chart has now become scientific data for everybody. Looking at the chart with my own eyes, is unquestionably no less then 750 verticle, but more like 800 to me, 775 to other 810 to others, 800 to me. What me and Nick was reporting is what we 'seen first hand' not what we seen from that .jpg that I captured from the tape after I got home. We moved and repositioned the camera to make sure we were correct. We only rolled tape once, and that's what you see. - ShannonRawls.com |
Shannon, you've been saying this, implying that the camera will do 800Hx800V in 24F, if I understand right. Does it mean that the German magazine also talks about progressive 800Hx800V resolution?
Since you have the camera, could you possibly shoot the resolution chart in 1080i and 1080p and post some frame grabbs, please. |
You're not really going to see a noticable rez difference in a still chart. It's not until motion comes into play that the resolution of an interlaced faux-progressive solution really breaks down.
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Joseph, facts please...what data do you have that the XL H1's image DOES break down with motion? Have you seen the "wheel" grabs I posted last month? They are very limited and at best semi-scientific test, but showed that the image did NOT break down; nor did the beautiful stills taken of the cat by Per Kristian Indrehus: http://www.dvinfo.net/conf/showthread.php?t=57163.
But anyway, gentlemen, THIS thread is supposed to be about HOW Canon achieves its excellent results. There are other existing threads with ad nauseum arguments about interpretation of the very few posted rez chart results (including Shannon + Nick, and mine) as well as other linked grabs and clips that are available... http://www.dvinfo.net/conf/showthread.php?t=57404 http://www.dvinfo.net/conf/showthread.php?t=56347 http://www.dvinfo.net/conf/showthread.php?t=56536 http://www.dvinfo.net/conf/showthread.php?t=55566 ...plus others. Let's keep this discussion on topic and if the old news on rez charts needs to be rehashed, do it in the existing threads on that topic. |
Pete,
Yes, I've seen your clips ... thanks for posting those, they were very helpful. (And, yes they also reveal some of the interlace capture artifacts.) I'm not sure how to say this without sounding like an ass, but an interlaced capture system *has* to lose true resolution (detail or information) if the picture has changed between field captures. Depending on how fast the motion, and how sophisticated the interpolation, the loss will be minimal or drastic. Canon's implementation looks very good for a realtime solution. It's not going to break a sweat yielding great results on a still chart. On a moderate speed vertical pan, you'll end-up with about half the vertical rez. If it's fast enough, the motion blur will negate the loss, though. |
http://www.eidomedia.com/test
The H1 resolution advantage over the FX1 appears at the center of the frame, unlike the FX1 which maintains consistent corner to corner sharpness without the color fringing of the Canon. Below are two side by side images taken directly from the above test and magnified to 300%. In each image, the Sony is on the left, and the Canon on the right. From the magnified images, it's apparent the Sony is lots cleaner, has about the same detail, and none of the offensive red/green chromatic aberration of the Canon. The resolution hype concerning this camera is totally out of proportion. http://vsdrives.com/graphics/Resolut...risongrab6.bmp http://vsdrives.com/graphics/Resolut...risongrab5.bmp |
HUH?? The Canon looks a lot better to me... funny how people see things different
ash =o) |
Folks, again, please put the resolution comparisons in the many existing threads about that topic, unless the comments directly contribute to a point you're making about deciphering the mysterious internal workings of the XL H1. That's the topic of this thread, and this discussion shall be limited to that.
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