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I am interested in recording the output from the component ports of HD cameras cheaply. It's got nothing to do with illegally recording HDTV etc. I have been reading a bit here and thought somebody here might know of a HDTV PVR, HD computer capture card, or other device that can cheaply do this?


The problem with the current arrangement is that the cheap HD cameras (HDV cameras from JVC and Sony) record in a highly compressed format that isn't very suitable for professional camera work. Lots of movement/waves on water can cause blocky images (more so than normal HDTV which uses very expensive equipment for compression) even panning shoots. When magnified upto a big screen the detail is not as good either, so not good for independent film production.


The only option we have, is to record the uncompressed (pure native visually exciting) images off of the component ports onto something not so bad. Uncompressed recoding can preserve most of the image quality, but even something that compresses to lower compression would be an improvement. 28.8Mb/s mpeg2 or better would be a minimum and anything upto uncompressed a maximum. Even something that compressed to firewire (or any computer interface) for recording by dvhs or computer would be an improvement. The regular video production solutions cost thousands at the cheapest to do this, thats more than some of the cameras.


Wireless HD transmitting solutions are also something of interest.


I've come here because I am interested in cheap solutions below $1000 (pref hundreds of dollars) and google gave me thousands of useless pages (I've spent many hours in the past). There are many in the same boat, with otherwise stunning little cameras.



Thanks


Wayne.
 

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Well, I have DVHS and Sony HDV HC1 cam so can give you some first hand experience with both albeit rather limited and nowhere near pro level. First few facts: prosummer JVC HDV cams use 1280x720 progressive video compressed with MPEG2 with GOP6 at 19.2 Mbps. DVHS can record MPEG2 video at 1280x720 and 1920x1080 at maximum data rate of about 20Mbps, it will record JVC cam video stream as is. Sony uses 25 Mbps MPEG2 stream with GOP15 at 1440x1080/60i in it's prosummer cams (FX1, Z1, HC1, A1). You can't record Sony HDV video to DVHS without recompressing down to about 20Mbps. The least expensive HDV camera on the market is Sony HC1 and at $2000 MSR with 10% to 15 % discount available at some places I wouldn't call it exactly cheap. Second cheapest HDV cam is probably twice that price at the moment. Now, the good news is slower panning and zooming on HDV is pretty good and there is very little artifacts I can see. There is a little blur when fast panning but I thnk the only reason people notice it right away is because HD is so clear and sharp that when the pan stops the difference between few frames is so obvious. In comparison I think SD is as blurry when still as HD is when fast panning and SD gets more blurry during pans as well. There are some cases where you can overelm MPEG codec with fast changes between the frames but that's rare, most of the time with carefull planning the picture is outstanding (since I only have HC1 that's what my opinion is based on). Just about all HDV cams will allow you to record standard DV for some very fast scenes if you so desire, so there is a fallback just in case, but I have not used it at all and doubt I ever will. As far as recording from component, there are some devices on the market that will do that but they're expensive and I would speculate the PQ will actually suffer. There are some threads on this forum on the subject. BTW I read somewhere that Lucas will be using A1 (pro version of HC1) for one of his upcoming movies. So maybe those HDV cams are not as bad as you may think.
 

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Thanks Pete,


Unfortunately the case is not quiet that simple, it normally costs tens of thousands to get the performance of a high level pro HD camera. There is a 28Mb/s mode on some DVHS but I am talking about recording analogue component to a format better than HDV.


I am on dvinfo examining HC1 (the finale A1 spec hasn't come out and it could be significantly better). If you pan fast, if something to big moves, if you shoot out a car window etc, etc, the list just goes on, even panning slowly will make things blur. On the JVC's progressive 720p it is acceptable enough for low end work, accept the blur in panning. But with Sony's 1080 cut down system they have pushed it too close to the edge and the problems are much worse. Careful planning of shots to get around this sort of problem, and accepting inevitable failure and lost of non repeatable shoots, is not very professional. You also get the additional problem that when you blow up the picture to cinema size the effects of compression at such a low data rate becomes more obvious. You can still use it professionally, but it should have been made better (that is why they are going to the professional HDV2 spec of 38Mb/s, similar in speed to the blue ray camera format). I am looking at a cheap way for HC1/JVC/PANA owners to achieve higher quality work, or anybody that wants to do cheap Independent film/doco. The older HD1/10 cameras are prevented from outputting live component, but currently I am asking about internal test connections/modes that could have enable it.


The component can afford significantly higher quality (better than 8 bit precision is preferable). Depending on the component, progressive versions of the interlace image maybe available, which gives much better results in compression than interlace images. Currently we are looking at the possibility better image quality can be gotten from using the CF mode to record de-interlace to tape. It is found that very high speed shutter can also improve compression quality. You should go over to the HC1 forum to check out the debates. While I say 28Mb/s would be acceptable minimum in progressive, I would prefer at least 50Mb/s.


Lucas is likely to be recording from uncompressed component, the picture is really good for a 1/3 inch chip. This is what I want to do, as it is a lot cheaper than pro grade HD cameras worth tens of thousands.


So if you can give me links, subject lines or key terms to search for those threads that would help.
 

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Quote:
Originally Posted by wayne23
I am interested in recording the output from the component ports of HD cameras cheaply. It's got nothing to do with illegally recording HDTV etc. I have been reading a bit here and thought somebody here might know of a HDTV PVR, HD computer capture card, or other device that can cheaply do this?


...


Thanks


Wayne.
Your question usually appears in the forum about once a month but this is the first time I've seen it referenced to an HD camera. Usually it is people who want to record the analog component outputs from their DirecTV receiver.


For an analog solution, with the limitations of analog and only two channel sound, try searching on "WVHS". That may be what you are looking for. The tapes aren't cheap, the units are no longer manufactured and the quality isn't perfect, but those units do take HD component video input.


For a digital solution, the bottom line is yes it can be done at a professional level and price. Is there a cheap way of doing it? - absolutely not.


Let's take a 1280x720 image at 30 fps. If we assume 24-bit color (the CMOS chips inside the camera really do limit the color depth) then we would have the equivalent of approximately 663 mbps streaming out of the camera. That's is a pretty hefty load for any image capture device! 1080i would bring this into the gigabits per second.


The next question is what are you going to do with the bits? You could store them but storing 83 mega*Bytes* per second is also a problem for a cheap solution. That works out to filling a 500 gigabyte HDD in approximately 100 minutes! Hitachi makes a 500 gigabyte SATA2 drive that has a burst rate of 300 mbps.


You could compress the output but then you'll need a CPU that can compress in realtime. Not cheap, either. But, that would bring you back to the solution that you are being provided by the camera. Even the professional solutions that I know of require some level of digital compression.


There are professional-level components that do this. JVC has some items that do this - but they are in the $20K+ range for each component.


There is much more written about this in various forum archive threads over the last few years.
 

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Thanks for that, now that I know there probably isn't a TV capture card (unless anybody else has something to add, as you guys would have discussed it enough times and know the answer) or HD PVR, that will take component HD compress and record it, I give up. But how do they capture w-vhs to a computer, through pro solution? Hopefully one of the guys over the alternative imaging forum at dvinfo will attempt to make one, but nobody seems interested so far. I already know a bit about the requirements already.


The figures for 720/25p are:

23.04MB/s+ for Single chip Bayer pattern record

34.56MB/s+ for 4:2:0

46.08MB/s+ for 4:2:2

69.12MB/s+ for 4:4:4


8bit, 10 and 12 bits are 25%-50% faster. The Sony is rumoured to have a 14bit sensor capture, but I would not expect any more than 10-12bit capture from it (if it is not locked to 8 bits anyway) which is fine.


1080 is just over double that.


The highest speed drives on the market will do between 50-70MB/s+ sustained, in upto 4 drive raid easily, and upto 500GB, a thousand times more than the 500MB you mentioned. Card busses go into Gigabytes per second and data throughput goes into tens of gigabyte per second for processors, though dedicated hardware/card tends to do it tens of times faster and cheaper. If it compresses to 28.8, 38 or 50Mb/s stream (MPEG2/4/wavelet etc) then you are getting less than 7MB/s stream, one cheap dedicated chip and drive. Can it be done on a PC in software, probably, but not through the usual sloppy programming that is used, there are pro camera capture solutions operating in around the 100MB/s range that I know of already.


Thanks


Wayne.
 

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Quote:
Originally Posted by wayne23
Thanks for that, now that I know there probably isn't a TV capture card (unless anybody else has something to add, as you guys would have discussed it enough times and know the answer) or HD PVR, that will take component HD compress and record it, I give up. But how do they capture w-vhs to a computer, through pro solution? Hopefully one of the guys over the alternative imaging forum at dvinfo will attempt to make one, but nobody seems interested so far. I already know a bit about the requirements already.


...


The highest speed drives on the market will do between 50-70MB/s+ sustained, in upto 4 drive raid easily, and upto 500GB, a thousand times more than the 500MB you mentioned. Card busses go into Gigabytes per second and data throughput goes into tens of gigabyte per second for processors, though dedicated hardware/card tends to do it tens of times faster and cheaper. If it compresses to 28.8, 38 or 50Mb/s stream (MPEG2/4/wavelet etc) then you are getting less than 7MB/s stream, one cheap dedicated chip and drive. Can it be done on a PC in software, probably, but not through the usual sloppy programming that is used, there are pro camera capture solutions operating in around the 100MB/s range that I know of already.


Thanks


Wayne.
I accidentally wrote 500 Megabyte in my append - it should have been 500 GigaByte. I've corrected it. That usually happens when I'm working on memory and then try to talk about storage.


The WVHS format stays analog once it is recorded. I don't know of anyone who records WVHS and then tries to digitize it. It basically stays analog - it is easier to start by recording digital if you want to use a digital format.
 

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As mentioned on other threads, capturing component to a PC is done by converting it to SDI and then capturing the SDI. Takes expensive and fast hardware, in the range of about $5000. And then you have to convert it down from the 50gb/hour native capture to something more reasonable.
 
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