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Old October 17th, 2005, 12:36 PM   #1
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Quality of video stills out of HDV?

If I consider buying an HDV camcorder for wedding and event videography, is the resulting frame grab useful for a 5 x7 inches print?
Can I charge extra for stills out of HDV video?

-EDWIN
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Old October 17th, 2005, 01:47 PM   #2
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To me 5x7's look great. One thing I really recommend for pulling stills off HDV is the uprezzing program Photozoom Pro. What I do is reduce the height by 50% in Photoshop to get rid of the interlace lines, then export to Photozoom Pro and resize to 200% height by 133% width using the spline algorythm and a little sharpening. You can uprezz further than that if you want, but that is the ratio you need to keep. You have to crop the ends of the 16x9 frame, but the end result looks realy good. A little color stretch in Photoshop is also necessary. Anyway, to my eyes, the results look like good photographs. There's something about capturing that exact moment, and that is what screen captures do so well.

Also, be aware that on the H1 and A1, you can preview footage on the camera, then press the photo button to capture stills anywhere you want. That is one of the reasons I went with the A1. If you end up downrezzing to SD on capture, this lets you get better stills than you would from the editor.
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Old October 17th, 2005, 07:53 PM   #3
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Just be aware that the GOP plays a part in the quality of the frame that you end up getting - especially if it's grabbed from an interlaced stream.

Movement, or more specifically the amount of it, that takes place in the frame is also something to consider - because there are MPEG compression algorithms working on individual frames at different rates. Frames with very little (or no movement!!) will be plenty good enough (with decent post processing) for 5"x7" prints.

The problem with capturing stills from the HDV stream is usually the ability of the program you're capturing with to retain the actual image quality. I now use Vegas to capture as interlaced PNG and then use Photoshop CS2 to de-interlace, adjust Pixel Aspect Ratio and resample from the grab's screen resolution.

I've used some grabs for newspaper reproduction, and the quality definitely surprised my usually 'reticent to accept anything new' colleagues.

The bottom line is... if you want a single frame from HDV to use for 5"x7" prints; it's very do-able - but it's not as easy as using a Digital Still camera - unless you're using one of the JVC cameras, as they offer still image capture. Problem is, you're then using a 1280x720 frame size -on the other hand, there's no likelihood of interlaced effects possibly entering the exact frame you're after: but, you have to remember to keep switching the camera between still and video modes...
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Old October 18th, 2005, 05:11 PM   #4
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If you use a progressive cam, like the JVC's, every frame is a still picture.

Steve-"Problem is, you're then using a 1280x720 frame size "

Why is that a problem? It is not the frame size but the detail within the frame. The Sony's pixel shifted 960x1080 chips, produce 1440x1080 frames which are then interlaced dropping resolution by about 25% bellow its stated format. The Sony's 15GOP vs. JVC's 6GOP also reduces the quality of stills captured from fotage. Then do not forget you get another resolution hit when you de-interlace the still.
If someone is wanting stills from HDV video the JVC's should be first on ther list. Problem is progressive cams do not lend themselves to low light, so weddings might not be best. My advice would be to aquire some footage then take a still out and see how you like it.
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Old October 18th, 2005, 09:03 PM   #5
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Quote:
Originally Posted by Ken Hodson
If you use a progressive cam, like the JVC's, every frame is a still picture.

Steve-"Problem is, you're then using a 1280x720 frame size "

Why is that a problem? It is not the frame size but the detail within the frame. The Sony's pixel shifted 960x1080 chips, produce 1440x1080 frames which are then interlaced dropping resolution by about 25% bellow its stated format. The Sony's 15GOP vs. JVC's 6GOP also reduces the quality of stills captured from fotage. Then do not forget you get another resolution hit when you de-interlace the still.
If someone is wanting stills from HDV video the JVC's should be first on ther list. Problem is progressive cams do not lend themselves to low light, so weddings might not be best. My advice would be to aquire some footage then take a still out and see how you like it.

It's been my experience; from capturing 720p stills from my JVC HD10u - as well as my Sony FX-1e, that the FX-1e 1440x1080 1.3333 PAR image is approx. double the effective detail of the 1280x720 1.0 PAR HD10u image.

Even after all the over-intellectualised, supposed pixel decimating processes you mention... a 1080i image is still more detailed for still image reprographics than a 720p one is.

I've printed grabs from both via a Xerox 1,200dpi colour laser and an Epson Photo 2100 at 1440dpi, and the images from the Sony grabs are not only more detailed, but more saturated in colour, with greater dynamic range. Grabs from the HD100 may be better because of the 3-CCD capture block, but even so... MPEG motion artifacts will be just as evident in a frame grab of 720p as they are in a 1080i screen capture, and they'll still be - in pixel terms - always below the starting point of 1080.

If I tried to argue with my newspaper graphic designer colleagues that a 1280x720 pixel image gave a better image than a 1440x1080 one - even with re-sampling etc. applied... they'd correctly assume I knew nothing about still image reprographics.
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Old October 18th, 2005, 09:47 PM   #6
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Thats funny becuse when the FX1 came out and there was a lot of comparison it was stated by quite a few people that the HD10 had slightly more detail. It lacked in dynamic range and colour saturation but lower detail was not a chief complaint. For you to say you see double the detail makes me question where you get you glasses. I for one do not see it.

"MPEG motion artifacts will be just as evident in a frame grab of 720p as they are in a 1080i screen capture"

Well that just isn't true in most cases, especially with any motion. If you are tripod mounted and there is virtually no motion in the shot, then the long GOP will be fine. Otherwise it takes a hit.

"If I tried to argue with my newspaper graphic designer colleagues that a 1280x720 pixel image gave a better image than a 1440x1080 one - even with re-sampling etc. applied... they'd correctly assume I knew nothing about still image reprographics."

The logic in that statement is very flawed. I could up-sample an XL1 image to 1440x1080 and give you a 1280x720 image from a HD-100. Who has the better image? Your newspaper graphic design colleagues would be wise to ask a few questions first. It is how those pixels are derived, compressed, processed ect.. The FX/Z1 does not resolve any more detail than a HD-100. The main differance is the HD-100 is showing its full 720p format(a single still frame), while the FX/Z1 is comming no where near 1080p (a single still de-interlaced frame). In the end they end up looking very close, except under high motion. 1080i deinteralced is so very close to 720p, that if it is a progressive frame that one seeks, why go interlaced? Extreem low light sensitivity asside.
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Old October 18th, 2005, 10:22 PM   #7
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Quote:
Originally Posted by Ken Hodson
Thats funny becuse when the FX1 came out and there was a lot of comparison it was stated by quite a few people that the HD10 had slightly more detail. It lacked in dynamic range and colour saturation but lower detail was not a chief complaint. For you to say you see double the detail makes me question where you get you glasses. I for one do not see it.

"MPEG motion artifacts will be just as evident in a frame grab of 720p as they are in a 1080i screen capture"

Well that just isn't true in most cases, especially with any motion. If you are tripod mounted and there is virtually no motion in the shot, then the long GOP will be fine. Otherwise it takes a hit.

"If I tried to argue with my newspaper graphic designer colleagues that a 1280x720 pixel image gave a better image than a 1440x1080 one - even with re-sampling etc. applied... they'd correctly assume I knew nothing about still image reprographics."

The logic in that statement is very flawed. I could up-sample an XL1 image to 1440x1080 and give you a 1280x720 image from a HD-100. Who has the better image? Your newspaper graphic design colleagues would be wise to ask a few questions first. It is how those pixels are derived, compressed, processed ect.. The FX/Z1 does not resolve any more detail than a HD-100. The main differance is the HD-100 is showing its full 720p format(a single still frame), while the FX/Z1 is comming no where near 1080p (a single still de-interlaced frame). In the end they end up looking very close, except under high motion. 1080i deinteralced is so very close to 720p, that if it is a progressive frame that one seeks, why go interlaced? Extreem low light sensitivity asside.
The personal attacks were uneccesary... Just keep to the facts. :)
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Old October 18th, 2005, 10:57 PM   #8
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A little fun jabbing in responce to you seeing DOUBLE the detail. Hardly a personal attack.
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