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Old April 2nd, 2006, 02:27 AM   #16
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Wow!!!

Wow man, that's pretty cheap for High def res. Let me ask though, how much hard drive space does it take up for say 1 min worth of 24 fps footage?
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Old April 2nd, 2006, 12:32 PM   #17
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Sorry to have been away for a while. ive been working on how to incorporate the 35mm adapter with the camera. im afraid the adapter would only be suitable for daytime outdoor shots, as i lose Alot of light with it on.

And for harddisk space. it is amazing. the recorded footage has a data rate of 1611 kb per sec. A 59 sec long peice of footage i recorded has a file size of 96,522 kb. (97mb) about. so thats about a minutes worth. thats with the jpeg compression setting on the camera set to 75%, i can take it all the way up to 99 if i want. but you really arent able to see any compression artifacts at 70/75% so its good enough for me. if you raise it up, everything stays the same, fps speed and such, only the file size in the end gets bigger.

But its not at all a huge filesize because it records to a mjpeg codec.

Wayne, im not sure how you want me to perform the tests, can you explain what to do so i can answer your question about the compression on the camera? thank you
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Old April 2nd, 2006, 03:53 PM   #18
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Hey!

Jef, and everyone else, i uploaded a video file which is straightly converted from the .ogm to .avi. its about 34 mb

download it here: http://www.savefile.com/files.php?fid=3526893

this means there is no extra post compression. sorry there is not much motion, just a handheld shot at 24fps showing different focuses with my c-mount lens. if your media player doesnt support mjpeg codec, youll need to download the codec, or download the easy and free media player vlc. http://www.videolan.org/vlc/
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Old April 3rd, 2006, 11:11 PM   #19
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Quote:
Originally Posted by Forrest Schultz
And for harddisk space. it is amazing. the recorded footage has a data rate of 1611 kb per sec. A 59 sec long peice of footage i recorded has a file size of 96,522 kb. (97mb) about. so thats about a minutes worth. thats with the jpeg compression setting on the camera set to 75%, i can take it all the way up to 99 if i want. but you really arent able to see any compression artifacts at 70/75% so its good enough for me. if you raise it up, everything stays the same, fps speed and such, only the file size in the end gets bigger.
..
Wayne, im not sure how you want me to perform the tests, can you explain what to do so i can answer your question about the compression on the camera? thank you
Well, that part answered it, 1611KB/s, is around 12.9Mb/s, half of MiniDV, around 1/8th of DVCPROHD, which is around 6:1 reduced 1080i res (I'm guessing you are talking about a 1080p image here) so that's around 48:1 MJpeg1, even higher if you are using full 1080p res. MJpeg is very similar to normal Jpeg, and a fraction of the performance of Mpeg2. What about at max settings? The most you can expect from MJpeg (which is similar to DVCPROHD) is performance of DVCProHD, over the 100Mb/s network. That is why Ogg is important, it was supposed to be the alternative to Mpeg2, where even Mpeg2 at 100Mb/s would really kick ass, but we don't know how suitable Ogg is. I examined some Ogg footage up close a month or two ago, and I noticed large colour blocks. Whenever I ask people who should know, about specifics, I get consistent silence, I suspect that there is fundamental bad news. This, apparent problem, may not be such a problem for me, but it definitely will be for others.

Sorry for the confusion about the compression thing, wasn't too well, and I didn't explain it properly. To measure compression just get the bytes per second and divided by, frame size times the frame rate times by the amount of data per pixel (in bytes). That will give you an idea of how much smaller than compressed footage si from the original.


Viewing distances for a Cinema effect, and display resolution:
There is a fundamental problem in how people examine HD footage for Cinema use, and lots of people do it. A big HD TV is meant to be viewed from a minimum distance that makes the screen look something like half the width that a really good Cinema seat should give you (similar to the coverage that the Imax seat would give you). 4:3 TV viewing distances are worse again. The extra wide effect makes the footage look like it has much less res, and makes the compression problems much more evident. So, what is widest, from private tests, nearly a wide glass lens width of image (after that vision goes into purely peripheral head turning vision), half that for a poor cinema seat. This is about half an eye full of vision, line up one corner of your single eye vision with the side of the screen, while looking straight ahead, and about the middle of your vision should be on opposite edge of the screen. Try it, HD footage looks a lot different. But, for HDTV work, things are much better, that is already heavily compressed.


Display resolution:
With Displays there are a few things they do that hide the problems, that should be looked at. One, they use odd, none genuine 1080 or 720 resolutions (indeed, even HDV 1440*1080 does this in camera) in the actual screen, that blurs the boundaries in between pixels, causing data from one pixel to integrate with another pixel. This hides some problems. Some displays use inputs that don't work at the full resolution they are receiving. Still others make a genuine attempt to clean up the image and get rid of artifacts, maybe even artificially restoring some lost detail. There are wide screen TV's that use genuine 720/1080 resolutions, in the past many didn't.


Jpeg problems effecting detail and resolution:
Jpeg is not so good at retaining detail, because it gains great performance from dropping detail, in DV codec at least, it also tends to be so imprecise also that you usually need a special version to do lossless compression. Examination of some of the links I have posted for filtered Raw Bayer from Web cams mods (in alternative imaging) compared to video camera footage shows much better line/edge sharpness. So, while it might retain a clean HD edge, you might notice that much detail in the image itself is dropped to lower resolutions. So the images should look less detailed, less defined, and blander. Our eye though, probably likes the high res edges and don't take to much notice. But on a big screen, the lower resolution is much more noticeable, and probably benefits as much as an slightly out of focus scene.
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Old April 4th, 2006, 06:09 PM   #20
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I agree with you Wayne, but the nice thing about the Elphel camera is that it is open source and develops and improves pretty fast.
As far as I know..and I hope I don't know much..there isn't a OGG Theora converter to AVI or other useful codec (or lossless format) in windows.

Forrest, what lens do you use on the 35mm adapter? If you use a 1.2 or less (meaning bigger) aperture, the lightloss will be no more than 1 or 1.5 stops.
Indoors you'd need a 500W light or more when using an adapter, what ever camera you use.
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Old April 4th, 2006, 06:22 PM   #21
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Amazing how I was dismissed by Elphel owner just like one year ago when I asked him about doing the same thing and he just said: "that is not possible".
Now, suddenly he is making one!!!
I guess I should be doing something really wrong when I talk to people.....
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Old April 4th, 2006, 08:00 PM   #22
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thanks for all the replys guys, I have a f1.7 50mm lens, and f2.8 28mm wide angle lens, and a 135mm f2.8 telephoto lens. so far i wasnt able to get good light transmission, but i think a big problem is the glass im using. i need to get a beattie screen, and build either a mechaincal osicillating adapter or a vibrating adapter similar to the letus with the beattie screen. that should offer alot of help in lightloss.

Other than that, the only factor i can think of is the portablility issue, so far, i think i will need to film near places with power outlets so i can run extension cords from the computer and such. but i will buy the beattie screen and build an adapter around that and then build the camera body to go around it all of it. simulating the style of a 35mm film camera. i also am making a homemade viewfinder also
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Old April 5th, 2006, 05:18 AM   #23
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Quote:
Originally Posted by Oscar Spier
I agree with you Wayne, but the nice thing about the Elphel camera is that it is open source and develops and improves pretty fast.
As far as I know..and I hope I don't know much..there isn't a OGG Theora converter to AVI or other useful codec (or lossless format) in windows.
VLC has a Ogg codec. They also have that linux disk, that should have lots of video options there, try Cinelerra and other Linux editors, you should strike something, then again, you can ask the commercial company that controls Ogg itself, they should know something. My, interest is Ogg, as I know it might deliver the extra quality. But then again, he is doing something in USB2.0, so that might help. The latest Ogg is also the choice for one of the Chinese HD DVD formats, so there is bound to be something out there, maybe even the possibility, even possibly the official Ogg enabled cheap DVD players.


Quote:
Originally Posted by Forrest Schultz
but i think a big problem is the glass im using. i need to get a beattie screen, and build either a mechaincal osicillating adapter or a vibrating adapter similar to the letus with the beattie screen. that should offer alot of help in lightloss.
There is another option. As far as I know, that if you put a lens through a suitable condenser it increases the effective aperture diameter, with the same FOV as the 35mm, so that the depth of field is the same as on a 35mm SLR camera but with lots more light. But once the aperture goes to much, the angle of light through the micro-lens will produce poor pref romance (except the Ibis5a, which has a 100% surface technique instead of micro-lens) and eventually it will be so much that light will bounce off the surface of the chip rather than goign in. Yes, apparently, 35mm adaptor can be done this way.
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Old April 5th, 2006, 05:41 AM   #24
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Quote:
Originally Posted by Juan M. M. Fiebelkorn
Amazing how I was dismissed by Elphel owner just like one year ago when I asked him about doing the same thing and he just said: "that is not possible".
Now, suddenly he is making one!!!
I guess I should be doing something really wrong when I talk to people.....
Yes, I remember, I have noticed that sometimes as well. After I saw your post I didn't bother either. But I think the issue is that somebody else is doing the work in this case.

With his design, it would be possible to put what ever codec you want to in the camera. 100Mb/s capacity, where as 24fps 720p 8 bit Bayer is 177Mb/s, so a simple lossless codec would fit. 498Mb/s for 1080p, there are some codecs that will get close to lossless at that rate (and he is talking USB2.0 soon). So you can do the FPGA stuff you wanted to do using this camera, and it is a low cost platform. Plus you can probably can use the existing Mjpeg codec FPGA design as a basis for a 720p design (see the news-net compression FAQs about what needs to be changed in Mpeg/Jpegs tables to make it true lossless).

It would be good to see you involved. Have fun.
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Old April 5th, 2006, 12:37 PM   #25
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The Ogg codec and DVD players with HD codecs

I mentioned HD codec DVD players somewhere, so relatives can watch it without a computer. I have also found the Ogg codec page, and more advanced commercial forms of it that beat H264 or WMP, that you might be interested in.

http://www.theregister.co.uk/2003/11..._killer_video/
http://www.reghardware.co.uk/2005/11...me_production/

The down loadable stuff is linked to these pages (these are the people that did the codec they use in Ogg, their VP3.2 codec, they are now upto version VP7):

http://www.on2.com/technology/vp7/
http://www.on2.com/video_samples/vp7-samples/
http://www.on2.com/company/

You notice that the PSNR maxes out around 36db, you get max compression on your upper 6 bits (36db, 48db=8bits) because there is less noise. Might be worth looking out for.

Ogg stuff:
http://www.theora.org/
http://www.on2.com/company/news-room...leases/?id=144
http://www.on2.com/company/news-room...leases/?id=124
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Old April 6th, 2006, 06:21 AM   #26
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Forrest, I was thinking..how about using a laptop to record the footage:
Close the laptop and carry it around as(or in) a bag on your back or something, and wire it to the camera, to a small keyboard to control the camera and to a small LCD screen to preview. You'd be pretty mobile with such a setup and fairly easy to do in stead of building a bigger 'Drake' like camera with mini PC integrated.
Just a thought, I'll give it a try anyway when I get my Elphel camera.

Last edited by Oscar Spierenburg; April 6th, 2006 at 02:06 PM.
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Old April 6th, 2006, 03:01 PM   #27
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high bit depth???

I looked at the avi video. So this is a 10 bit / chan. camera ? Or more ?

Other than potential bit depth, this video did not demonstrate any advantages over video from an off the shelf HDV camera. In fact, the resolution looked rather sub HD.

So how about some stills of the high bit depth, I'd love to see the color grading latitude of the camera.

-L


Quote:
Originally Posted by Forrest Schultz
Jef, and everyone else, i uploaded a video file which is straightly converted from the .ogm to .avi. its about 34 mb

download it here: http://www.savefile.com/files.php?fid=3526893

this means there is no extra post compression. sorry there is not much motion, just a handheld shot at 24fps showing different focuses with my c-mount lens. if your media player doesnt support mjpeg codec, youll need to download the codec, or download the easy and free media player vlc. http://www.videolan.org/vlc/
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Old April 6th, 2006, 03:37 PM   #28
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Quote:
Originally Posted by Oscar Spier
As far as I know..and I hope I don't know much..there isn't a OGG Theora converter to AVI or other useful codec (or lossless format) in windows.
you could use a windows build of ffmpeg for that :)
But i don't thinks it's a good idea to use the theora codec, it's too old (design-wise) and almost not supported by anything.
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Old April 7th, 2006, 12:49 AM   #29
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Quality is what matters for a Digital Cinema camera. Ogg is an alternative to mpeg2, it may even be a lot newer and more efficient. There is bound to be a Linux editor that does it. Ogg hopefully will give you the max quality, in a usable form (if Ogg does large colour blocks bigger then 4:2:0, then maybe not) Mpeg1 simply can't get the same quality for equivalent bandwidth.

From Ogg format you could transcode to whatever is needed, but for film transfer, a big standard lossless format could be sued. If it does have the quality, for HD/DVD, the transcode might still retain more quality then HDV.
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Old April 12th, 2006, 05:47 PM   #30
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Guitar Man

Alright, sorry for a long delay period. i did some tests just today at about 3:30 pm

And here they are, they are outdoor shots, all shot at 24fps. these are just stills from the actual footage and have not been enhanced or color corrected in anyway. i realized later i had the exposure just a little too hot. but not too bad.

http://i11.photobucket.com/albums/a162/vericetti/1.jpg
http://i11.photobucket.com/albums/a162/vericetti/2.jpg
http://i11.photobucket.com/albums/a162/vericetti/3.jpg
http://i11.photobucket.com/albums/a162/vericetti/4.jpg
http://i11.photobucket.com/albums/a162/vericetti/5.jpg
http://i11.photobucket.com/albums/a162/vericetti/6.jpg

AND HERE IS THE FOOTAGE YOU'VE BEEN WAITING FOR!!!..

http://www.savefile.com/projects.php?pid=967631
its at half the resolution, but still very clear and powerful. take a look! (click on the "Me Playing Guitar in the Back")

Last edited by Forrest Schultz; April 12th, 2006 at 10:16 PM.
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