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Photo for HD Video (D-SLR and others)
HD from Nikon D90, other still photo cams (except EOS 5D Mk. II, LUMIX GH1).


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Old February 25th, 2007, 05:09 PM   #31
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actually capitalizing MB means megabyte, but the lowercase on the second b means megabit: Mb. there is a convention somewhere. google it.
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Old February 26th, 2007, 07:40 AM   #32
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I can take an guess on that. Let's say that HDV 720p and DVCPROHD 720p are roughly equivalent (less some resolution in DVCPROHD at 30p), when not moving, or much noise etc. 35mb/s is around half that of DVCPRO (probably a bit worse). That is 9mb/s in mpeg2 terms, Sanyo uses Mpeg 4, that will give about 50% better quality (if we are lucky) which is around 13.5mb/s in Mpeg2 terms, or over 50mb/s in Mjpeg quality with still picture and no noise.

Guess what it is for Mpeg2 and Mpeg4 with plenty of noise and/or movement. 9mb/s Mpeg4 should probably be basically equivalent to 13.5mb/s MJpeg, and Mpeg2 at 9mb/s, probably equivalent to 9mb/s of MJpeg. I don't know if I am totally right, but I think this maybe the case.
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Old February 26th, 2007, 07:48 AM   #33
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They really needed to double the data-rate, or (more practically) use Mpeg4, VC1, On2's VP7/8, H264, even intra compression. Isn't this what we expect from MJPEG compression video formats on still cameras.
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Old March 1st, 2007, 08:33 AM   #34
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How to Output from Computer to HDTV?

How can you manage the HD-video you get from this camera, in a practical and economical way? Buying 100GB of camera cards doesn't sound very appealing. That's why tape is still so popular------lots of cheap space. Continually shuttling the footage in and out of the computer with camera cards, so you can play past clips out of the camera, would be a real bother.

If you don't have a new Vista computer with DVI/HDMI or HD component, what do you do, besides watch it on your computer monitor? Any non-nVidia graphics cards you'd recommend that have any or all of these outputs? I've tried to install an nVidia GEForce 5200 and it is not compatible with my nVidia programs that were bundled with the computer. Maybe that's why it's only $500., because they'd get you to spend so much on cards and all the other things you'd need for playback from storage. Do you suppose they supply you with a software program that provides some solutions to these problems?
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Old March 1st, 2007, 08:41 AM   #35
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Isn't this what we expect from MJPEG compression video formats on still cameras.
But that's exactly what this camera is: it's a Canon PowerShot, which is first and foremost a still photo camera; and that product line has always used Motion JPEG for its video clips. I'm not sure how you could have expected anything else.
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Old March 1st, 2007, 09:34 AM   #36
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Sorry, how I wrote it wasn't quiet clear. That is what I meant, this is the quality we expect from still cameras, we usually have to buy the manufacturers video cameras for better. More could be done though, sanyo was only an minor step in this direction.
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Old March 1st, 2007, 09:36 AM   #37
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Originally Posted by J. Stephen McDonald View Post
How can you manage the HD-video you get from this camera, in a practical and economical way? Buying 100GB of camera cards doesn't sound very appealing. That's why tape is still so popular------lots of cheap space. Continually shuttling the footage in and out of the computer with camera cards, so you can play past clips out of the camera, would be a real bother.
J

There are mobile hard drive enclosures that have card readers to backup cards on the spot to the hard drive. There was an cheap company that I found that did these things years ago. I have one of their re-badged combination 5 button trackball+mouse, but they are the only ones I know of that do an 8 button, wireless trackball+mouse. So they might be googable that way.

Recently camera companies have gotten onto this scheme as well, even through wireless digital still camera networking protocols.
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Old March 1st, 2007, 09:38 AM   #38
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This could be a great crash cam IMHO

This could turn out to be a great crash cam where you don't need audio and don't want to risk your more expensive gear, not just an excellent vacation/baby cam. Footage from a model airplane, fastened to a motocross cycle while jumping, POV shots like from a helmet ( though my skydiving days are long over and you'd never catch me jumping my Harley ). Used to shoot super8 flim a couple years ago and this will likely be better quality than Kodachrome reversal was before they stopped making that for S8. I've had a Canon SD500 point and shoot for a few years and though it isn't Canon's best still camera for movies, the 640X480 30FPS isn't bad. CurrentTV used some footage I shot with it on their website back when they started out of the first Bay Area user meetup they had. Josh Wolf was in that footage who now holds the world record, doing federal time as a journalist protecting his sources, so maybe I should hunt that edit up. I'd rather have a 24fps mode too, but it is what it is, should be great. The TX1 uses AVI (Image data: Motion JPEG; Audio data: WAVE (Stereo)) and looks like it has a wind reduction mode on the audio and well as maybe a manual level, so might do better on audio than my SD500. Am getting an HV20 from B&H, so don't have money now for the TX1, but in the future I'm there if I come into some extra cash.
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Old March 1st, 2007, 09:54 AM   #39
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Sorry, how I wrote it wasn't quiet clear.
My apologies for misreading your post, Wayne. And I certainly agree with you that more can be done.
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Old March 2nd, 2007, 08:17 AM   #40
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Is This Bit-rate Really Correct?

When you consider that the HDV mbps rate of 25 is to encode a 1,440 X 1,080 picture, the 35 mbps of the TX1 is extremely high for its smaller pixel-size. The TX1 produces a picture of just 921K pixels, compared to the 1,555K pixels of HDV. That's 68% more pixels for HDV, for just 71% of the TX1 mbps rate. That's 2.36 times as many pixels per mbps. Maybe, they'll tell us there was a misprint in the specs??
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Old March 2nd, 2007, 10:55 AM   #41
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When you consider that the HDV mbps rate of 25 is to encode a 1,440 X 1,080 picture, the 35 mbps of the TX1 is extremely high for its smaller pixel-size. The TX1 produces a picture of just 921K pixels, compared to the 1,555K pixels of HDV. That's 68% more pixels for HDV, for just 71% of the TX1 mbps rate. That's 2.36 times as many pixels per mbps. Maybe, they'll tell us there was a misprint in the specs??
Bitrate isn't everything. The efficiency of the codec is equally important. HDV is MPEG-2, which is way more efficient than MJPEG. However it is hard to compare the two, since with MJPEG each frame is a keyframe and so any artifacts which are motion based are completely absent.

Basically I would say that MPEG-2 is like 3-4 times more efficient than MJPEG for scenes with little movement.

However for high motion scenes MPJEG really shines and MPEG-2 struggles.

I think that this cam will wonderful for mouting on helmets and other places where you see lots of shake and movement, since MJPEG would have no marcoblocking at all.
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Old March 2nd, 2007, 10:57 AM   #42
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I would LOVE to see video clips from this little camera. Anyone know a place to find one? Lots of Canon sties have images but no video! Not that I can find anyway...
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Old March 2nd, 2007, 11:12 AM   #43
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I think that this cam will wonderful for mouting on helmets and other places where you see lots of shake and movement, since MJPEG would have no marcoblocking at all.
It depends on the data-rate of the MJpeg, their is an example on the wikipedia about it, I think at 6:1 and beyond there is significant macro blocks. By the looks of it, this means that you can get them on complex still images as well :(. Is this camera using 4:2:0, instead of 4:2:2, if so this might go an long way to reliving this by reducing the amount of data to be compressed. If they had done 70mb/s+, then I think it would have been great.


The Elphel camera in our alternative imaging forums uses similar ratios of compression, and blocks are there, and people use filters top get rid of them.
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Old March 2nd, 2007, 04:40 PM   #44
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Is this camera using 4:2:0, instead of 4:2:2
That is a very good question. Which begs the question, what color space do existing Canon digital cameras use for video? I have one. Is there a way to find out from the AVI file?
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Old March 2nd, 2007, 04:53 PM   #45
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what color space do existing Canon digital cameras use for video?
Color space is not manufacturer specific. It is format / standard specific.

HD-SDI, DVCPRO HD is 4:2:2

HDV and PAL DV is 4:2:0

NTSC DV is 4:1:1

See http://www.adamwilt.com/DV-FAQ-tech.html#colorSampling for more info.
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