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Brian Jacobs
Portable Capture System
on Sep 17, 2008 at 3:44:26 pm

I'm designing a prototype of a portable capture system. I would like information and feedback from professionals as to the practical viability of such a system.

Questions I have are...

1. I've seen footage from latest high-end CMOS based cameras using long GOP compression....seems like fast-moving parts of image within frame lose clarity.....even when using fast shutter speed...Is this due to high compression within camera or inherent problem with responsiveness of CMOS sensors....i.e., would this problem dissapear if one were able to capture uncompressed 4:2:2 8 or 10-bit via HDMI / HDI-SDI...?

2. Downstream from capture, would professionals working with existing editing hardware/software be able to easily incorporate the uncompressed footage into their workflow....?

I'd be grateful for your input..

Brian Jacobs


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john sharaf
Re: Portable Capture System
on Sep 17, 2008 at 4:09:10 pm

Brian,

No "high end" camera system uses long GOP recording compressions, only consumer and "pro-sumer" units do.

The best compression scheme available at the moment is the AVC-I implementation that Panasonic is offering on their high end cameras like the "3000". What distinguishes this format is that it's full 10bit, does not horizontal downrez (full 1920 raster) and uses half the bandwidth of their previous best format (DVCPRO100) at equal quality, or offers double the quality (equal to D5) at the same bandwidth.

Don't worry about the post production implementation as the players in this arena have to respond to whatever is become popular, especially as it catches on in volume.

JS



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Brian Jacobs
Re: Portable Capture System
on Sep 17, 2008 at 4:30:29 pm

Thanks for your response...

I'm actually talking about pro-sumer cameras (sub 10,000 dollars...?) like Sony PMW-EX1 or EX3 etc....I asked these questions of Don Greening on another CC forum and he advised me to post it to the Sony Cine-Alta forum.....

I'm talking about overcoming the capture and storage limitations of the pro-sumer (sub 10,000) cameras by providing a truly portable solution capable of 8-bit or 10-bit 4:2:2 capture in either AVI or MOV format....

Brian



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Craig Seeman
Re: Portable Capture System
on Sep 17, 2008 at 4:35:12 pm

I believe Convergent Design is working in this area so you'd have to think about what they're doing and how you can make yours better/different.

http://www.convergent-design.com/index.html




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Don Greening
Re: Portable Capture System
on Sep 17, 2008 at 5:02:23 pm

[Craig Seeman] "I believe Convergent Design is working in this area so you'd have to think about what they're doing and how you can make yours better/different. "

Thanks, Craig. In previous dialogue with Brian I had eluded to Convergent Design's products, but obviously not strongly enough. I think that company's Flash XDR device is just what Brian is looking for.

- Don



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Brian Jacobs
Re: Portable Capture System
on Sep 17, 2008 at 6:46:56 pm

Don,

I know about Convergent Designs products and specifically the Flash XDR.....wasn't ignoring your pointer in that direction.....

I'm interested in exploring the advantages of working uncompressed.

Wafian HR-F1 is closer to what I've been working on.....with this major difference - the Wafian is a big box and limits camera movement unless you have someone to carry it around with you..... whereas what I'm after is a wearable system that allows better camera movement......

I can make a testing prototype in two weeks with my own money (I've been working on the design for a while) - the question is - is it worth doing.........? or are the existing codecs employed by the sub 10,000 dollar cameras delivering enough quality......i.e. is there any real-world advantage in being able to bypass camera internal compression and get AVI or MOV uncompressed files.......that's really the question I'm trying to get a clear answer to, from working professionals such as yourself.....

I appreciate your continued input on this issue....


Brian.





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Michael Palmer
Re: Portable Capture System
on Sep 18, 2008 at 4:29:57 am

Convergent Design's Flash XDR compact flash recorder allows the end user to choose the compression needed for the project. Unless you plan on using the Sony HD Cam SR deck to record you won't come close to the lower levels compression it can deliver. The compact flash design is the future of our business, and no hard drive system will ever compete with field work.

http://forums.creativecow.net/readpost/142/860531




Good Luck
Michael Palmer


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Brian Jacobs
Re: Portable Capture System
on Sep 18, 2008 at 5:15:44 am

Thanks for your input Michael...

Brian...







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Craig Seeman
Re: Portable Capture System
on Sep 17, 2008 at 4:32:05 pm

[john sharaf] "No "high end" camera system uses long GOP recording compressions, only consumer and "pro-sumer" units do."

I hate when people use terminology like this.
I wouldn't call XDCAM 335, 355 or the eventually arriving 700 "pro summer" and they're all Long GOP to XDCAM disc.
The XDCAM EX series is full 1920x1080 sensors and is Long GOP to SxS cards. HD-SDI out is 4:2:2 10 bit Uncompressed and never touches the XDCAM compression so that's not Long GOP at all.

The above cameras certainly serve ENG and Corporate video market and, in some cases, lower budget cable and broadcast TV.

AVC-I and DVCPro100 have their own set of issues otherwise people wouldn't be using the above Sony Cameras. While these two codecs are not Long GOP, they certainly are compressed and certainly have various workflow issues. Codec and Long GOP are only one factor to consider when using a camera and creating an efficient production/post production workflow.

The same can be said for CMOS vs CCD. RED is CMOS for example. Certainly CMOS is in less expensive cameras compared to their competitors (Even RED is a less expensive competitor against higher end cameras). In the "real world" cost is a factor too.

There's also chip size. Some find the EX's 1/2" chip and 1920x1080 sensor size worth the sacrifice of CMOS and Long GOP because of quality & price combination. They are certainly used in Professional environments and, when handled with an understanding of the limitations, excellent professional quality.

I wound not call a Sony F355 "prosumer" even though it's Long GOP but that's just me. Nor would the 700 be (when it comes out). I wouldn't call RED "prosumer" either even though it's using CMOS. I don't consider the EX "prosumer" either. I don't think one would mistake them for a Viper or F35 either but not every professional production calls for those.

I certainly wouldn't call Long GOP "prosumer" and DVCPro100 professional. They both have problems (and advantages) as codecs.






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Steve Connor
Re: Portable Capture System
on Sep 17, 2008 at 4:50:06 pm

I'd agree with that 100% Nothing "Pro-sumer" about the XDCam series. Very inflammatory comments for a Sony forum.

Steve Connor
Adrenalin Television

Have you tried "Search Posts"? Enlightenment may be there.


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Brian Jacobs
Re: Portable Capture System
on Sep 17, 2008 at 5:04:46 pm

Craig, your comments noted...thanks...I'm always at a loss myself as to what constitutes 'prosumer' and what 'professional' - I've just drawn an arbitrary line at 10,000 dollars and I'm looking at people using sub 10,000 dollar cameras.....

as my father said 'confusion is the one guest that never refuses an invitation'....

Basically, what I'm designing is something that will take the HDMI or HD/SDI output from a HD (1920 x 1080p) sub 10,000 dollar camera such as the Sony EX1 or EX3 and capture to a hard disk array, sort of like some Convergent Design products, but in a form that will incorporate a complete wearable solution (as a backpack) and allow the cameraman complete freedom of movement, virtually unlimited hours of shooting (say 8 hours a day). Very ambitious. I was a computer geek before I turned to video, so I know I can do it, using existing components....question is 'Is it worth it...?' ....question 2 has been answered...thanks...question 1 remains.......

1. CMOS based cameras such as Sony EX1 - fast moving objects (tennis game, cars on a highway) get blurred, even when shooting at fast shutter speeds.....my question is this - Is this blurring due to compression within camera or an inherent problem with responsiveness of CMOS sensors....? this has direct relevance inasmuch as if it is a problem with responsiveness of CMOS sensors, then it won't be solved by bypassing the cameras compression....however, if it is not due to the sensors, but due to the compression, then it should be solved by capturing uncompressed direct from HD-SDI port........?

Brian...



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Steve Connor
Re: Portable Capture System
on Sep 17, 2008 at 5:10:00 pm

I have to say I disagree with this statement, we primarily use EX1's for shooting aircraft at air displays and we get no issues with blurring (except when I get the focus wrong!) and some of these are travelling at very high speeds.

Steve Connor
Adrenalin Television

Have you tried "Search Posts"? Enlightenment may be there.


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Brian Jacobs
Re: Portable Capture System
on Sep 17, 2008 at 5:25:06 pm

Great, thanks for that info Steve....very much appreciated...

Would there then, in your opinion, be no advantage as far as image clarity goes to being able to capture uncompressed, as opposed to using the cameras inherent compression.....?

Are you shooting full 1920 x 1080p.....?

Any difference in clarity of fast-moving objects shooting 1080p vs 720p....?

Any difference in clarity between objects held in frame (ex panning with the aircraft) as opposed to a stationary frame with the aircraft moving from one side of the frame to the other (assuming aircraft size in frame is about 1/8th entire frame....?

I understand that Sony advises using 720p rather than 1080p to get clarity at speed.....is this correct....why......?

Brian....



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Craig Seeman
Re: Portable Capture System
on Sep 17, 2008 at 7:20:04 pm

I'll add to what Steve posted especially since you mentioned Tennis previous to it.
I have a Tennis client I do video for. It ranges from web to digital signage to local cable spots.

For various reasons I've shot 720p60, 720p30/60, 1080i60.
The XDCAM codec does not break in my experience. Actually some really challenging tests are not obvious. Running water or waving leaves on a breezy day are MAJOR FAST ACTION. Fast action is pixel by pixel change from frame to frame or field to field (depending on shooting mode) and the codec does NOT BREAK (unlike HDV). HDV is 25mbps CBR (easily broken) whereas XDCAM is 35mbps VBR and that's a world of difference.

All HD broadcast is either 720p60 or 1080i60. 60 "units" per second gives you best temporal resolutions. 1080p30, having only 30 "units" (I say units because p60 is frames and i60 is fields) has only 30 "units" per second. Obviously having 60 discreet "snapshots" per second has more greater capacity for motion detail.

Shutter speed certainly has impact too but that should have no impact on your product since it has no impact on data per "unit"

BTW a key thing to consider when creating such a device is record data rate. XDCAM playback data rate is 35mbps VBR, record can be much higher. Someone shooting at 720p24/60 for slow mo may be hitting something like 87mbps on the record side. In fact that's one of the reasons why SxS cards are so expensive. In fact most Express cards can't sustain 35mbps (people are testing with the 1.11 EX1 firmware as well as the EX3 current firmware).

One big advantage of HDSDI out is the "color space" if one is doing heavy compositing and that the source file comes from the camera before XDCAM codec compression. This would be similar to HDMI HDV cameras (Sony V series comes to mind).

There's all sorts of potential engineering issues when it comes to read, write, reliability things when it comes to hard drive vs flash type recorders. Convergent Design is Flash based. Some might remember a company (Specialist Communications?) that was working on a hard drive based solution for P2 cameras. They abandoned the projects as P2 card prices dropped. Of course they were dealing with a 100mbps codec (although can be less for those who know why you get more P2 recording at 720p24 vs 1080p30).



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Oliver Heuft
Re: Portable Capture System
on Sep 18, 2008 at 9:30:15 pm

Hi Craig,
i own the EX3 and tried to freeze fast tennis motion. What settings would you propose to get best results (not blurry): fomat, shutter speed, shutter angle?, fokus (manual or autofokus). My results at the moment (PAL, 720p, 50fps) are horrible.

THX in advance. Oliver





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Craig Seeman
Re: Portable Capture System
on Sep 17, 2008 at 7:23:13 pm

I'll add to what Steve posted especially since you mentioned Tennis previous to it.
I have a Tennis client I do video for. It ranges from web to digital signage to local cable spots.

For various reasons I've shot 720p60, 720p30/60, 1080i60.
The XDCAM codec does not break in my experience. Actually some really challenging tests are not obvious. Running water or waving leaves on a breezy day are MAJOR FAST ACTION. Fast action is pixel by pixel change from frame to frame or field to field (depending on shooting mode) and the codec does NOT BREAK (unlike HDV). HDV is 25mbps CBR (easily broken) whereas XDCAM is 35mbps VBR and that's a world of difference.

All HD broadcast is either 720p60 or 1080i60. 60 "units" per second gives you best temporal resolutions. 1080p30, having only 30 "units" (I say units because p60 is frames and i60 is fields) has only 30 "units" per second. Obviously having 60 discreet "snapshots" per second has more greater capacity for motion detail.

Shutter speed certainly has impact too but that should have no impact on your product since it has no impact on data per "unit"

BTW a key thing to consider when creating such a device is record data rate. XDCAM playback data rate is 35mbps VBR, record can be much higher. Someone shooting at 720p24/60 for slow mo may be hitting something like 87mbps on the record side. In fact that's one of the reasons why SxS cards are so expensive. In fact most Express cards can't sustain 35mbps (people are testing with the 1.11 EX1 firmware as well as the EX3 current firmware).

One big advantage of HDSDI out is the "color space" if one is doing heavy compositing and that the source file comes from the camera before XDCAM codec compression. This would be similar to HDMI HDV cameras (Sony V series comes to mind).

There's all sorts of potential engineering issues when it comes to read, write, reliability things when it comes to hard drive vs flash type recorders. Convergent Design is Flash based. Some might remember a company (Speclalist Communications? BTW deliberately misspelled because COW seems to think I'm posting a "male enhancement" item) that was working on a hard drive based solution for P2 cameras. They abandoned the projects as P2 card prices dropped. Of course they were dealing with a 100mbps codec (although can be less for those who know why you get more P2 recording at 720p24 vs 1080p30).



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David Issko
Re: Portable Capture System
on Sep 17, 2008 at 10:46:43 pm

Brian,

Just a note to let you know that CD will have an upgrade to uncompressed for their XDR recorder soon after the unit is readily available.
Cheers
David Issko



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Mark Espina
Re: Portable Capture System
on Sep 18, 2008 at 2:06:24 am

Hi Brian,

I would be very interested to check-out a portable HD-SDI recorder for the EX which I'm sure would also be compatible to other cameras with an HD-SDI out.

At the moment, as far as I know, one can only do this by having a workstation with an appropriate capture card (Kona, BM or others) on set/location which would be connected to a power outlet. Your camera would then be connected via cable - limiting its movement.

To have an untethered unit which would be able to capture uncompressed 4:2:2 10bit signals from the camera would be fantastic.

There would surely be a market for this.

Build it and they will come (or buy in your case).

Oh, and when you do get it working - make it affordable enough for us indie filmmakers.

Cheers.



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Brian Jacobs
Re: Portable Capture System
on Sep 18, 2008 at 3:14:20 am

Mark,

thanks so much for your valued and much needed positive feedback...

Your point re affordability is in fact one of the reasons I am confident that this will work.....

When I have a prototype ready, I will be looking for people to test it....

My email address is - bricyn786@yahoo.com - please mail me directly with your contact details so I can keep you updated on progress. Once its ready, we can make work out a schedule for testing.

Brian Jacobs.







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Paul Marshall
Re: Portable Capture System
on Oct 22, 2008 at 9:08:55 pm

Hi Brian,

I read this thread with interest as I am in the market for such a device, along with an EX-3. I work at one of the small ITV regions in the UK, mainly on news/sport/current affairs docos and commercial and corporate but it's the standard definition news environment that I am interested in with this camera. (I appreciate that it ain't "built tough" but it should survive in my hands)

The main reason I'm interested in a separate recording device is to be able to record standard def straight onto low cost, easily changeable disk - Compact Flash ideally. In the fast paced news environment I can't spare the time to be able to do lengthy down-conversion to enable our editors to do their thing on our Avid server system.

Sony make just such a device that I believe comes with one or two of their "prosumer" models. It will also be available separately apparently. It will work via I-Link on other cams, such as the EX-3.

I don't know if this helps you but it might give you an insight into what different people are after. Also, I don't know how practical your backpack solution will be. Sure, some people will accept this for ultimate quality in certain situations but it's not a road I would willingly go down for many reasons. I'm not sure either that many people need such high recording capacity either, there are only so many hours in a day! Wildlife shooters might be grateful I suppose!

Another thought for you...I've been researching this whole subject for some time and I recall reading somewhere that the variable frame rate function does not record via the HD/SDI out - only to the SxS card. I'm not sure yet if VFR will record via I-Link. Any ideas anyone?

One final thought though. I'm sure that this camera could easily find it's way into the news gathering arena but lack of SD recording is a big issue (at least for now). In fact I don't really understand why Sony didn't build this in. Firmware update possible anyone?

I'm brand new to this forum so Hi all and thanks for the fascinating posts. I also apologise in advance if I have my facts wrong.

P.S. If anyone is wondering why I want to go to this level of hassle to shoot news, it's because I have serious back problems (20 years in this industry does that) and so I have to lighten my load. Also not prepared to drop below half inch sensors for DOF issues.

P.P.S. Brian, there is a yet to be made product that really would transform the EX-3 into a serious piece of kit for all users that are used to pro shoulder mount cameras, and I don't just mean a shoulder brace! I have the design worked out in my head but no ability to take it further. If you'd like to e-mail me directly we may be able to come up with something to our mutual benefit.

But good luck with everything!!


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Brian Jacobs
Re: Portable Capture System
on Oct 23, 2008 at 1:58:04 am

Paul, hi...

Thank you for your thoughts and comments.

My email address is bricyn786@yahoo.com
Please do feel free to get in touch with me directly so we can discuss your idea....

I expect to have my first prototype ready for testing in a couple of weeks....I'm waiting on a component to arrive from China...The latest configuration of my design provides for over 5 hours of uncompressed HD capture....

I can easily downscale my design for SD, if you indicate to me how many hours of SD you need to be able to capture and what kind of additional weight you can carry.

Brian Jacobs.

Brian



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