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November 13th, 2006, 10:19 PM | #16 |
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my take on analog out
So....the analog out on these types of camcorders is USUALLY pre-compression - that is, the image hasn't been run through the losses incurred by HDV or DVCPRO HD compression. That is GOOD.
HOWEVER...this is analog output, not digital. And it is the analog outputs on sub $10,000 cameras...I get the impression this isn't going to be the best quality analog circuitry in this class of camera - it really was only intended for monitoring purposes. ALL HD tape formats are digital. So...the analog route means you skip the horizontal subsampling, the compression artifacts, etc. which is good....but then you suffer digital to analog to digital losses. The image is softer having gone through the process. I haven't finished analyzing the analog vs. digital stuff from Texas HD Shootout, where I capture both ways for comparison's sake. Ideally, you'd capture over HD-SDI.
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November 13th, 2006, 10:45 PM | #17 |
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Or HDMI, but that's another thread.
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November 14th, 2006, 08:58 AM | #18 | |
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David, I was just thinking about that.
I would be interested in the extra color info for keying. I was thinking this would be more of a hassle than it's worth, but You could record to tape in HDV while at the same time through component to get the 4:2:2 for a key and then use the mat on the HDV video. That probably wouldn't work out well, but it was just me thinking out loud. Also from what I read here component out is only 60i. Quote:
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November 14th, 2006, 09:34 AM | #19 |
a couple of comments:
chris: it's just semantics, but, to my way of thinking 4:2:2 isn't really "compressed", just capture of less than all the available data. Compression implies, to my mind, a mathematical processing technique to reduce a file size. As I said,,,,this is somewhat academic to argue the points of semantics. Uncompressed implies native capture...in this case, even if it is 4:2:2. Analog vs digital is just the means of capturing the data, digitized/dithered 0's and 1's vs a continuous analog stream. One could agrue that ALL digital data is compressed, since it records only discrete snapshots in time rather than a continuous stream. Now that i think about it, analog capture is discrete frames in time, so where's the "continuous stream? LOL 30 FPS could be considered uncompressed compared to 24 FPS. the faster the frame rate, the more "uncompressed" it is, yes? oh well...word games. So, it remains to be asked whether analog capture of 4:2:2 at some frame rate is more uncompressed than digital 4:2:2 at the same frame rate. And, which method gives the best final picture...after all, it's the final picture quality we're all interested in. Why can't someone like Videonics(Firestore) capture digital 4:2:2 (HD-SDI) on a firestore device, instead of .m2t streams? This would mean, of course, that the firewire input would have to be replaced by 3 component RCA plugs for component input, or one SDI BNC plug for HD/SD-SDI, since by the time the signal gets to the firewire bus, it's been compressed to 4:2:0. Oh, and HDMI is EXACTLY the same video signal as DVI. The only difference is that HDMI has two channels of audio integrated into the connector rather than seperate RCA connections. As far as the video signal is concerned, the quality is identical to DVI. Last edited by Bill Ravens; November 14th, 2006 at 10:14 AM. |
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November 14th, 2006, 09:58 AM | #20 |
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Well if you are talking about compression relative to the camera then 4:2:2 is uncompressed if that is all the info the A1 can capture. so I guess it is uncompressed it's just not a 4:4:4 camera.
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January 10th, 2007, 09:43 AM | #21 |
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A1 analog component
I am curious about the use of the analog component out of the A1. We know the analog out circumvents the HDV codec entirely and outputs 4:2:2 uncompressed 8-bit (semantic differences on whether the term "uncompressed" even applies to analog, notwithstanding). This can be a very good thing.
However, the analog component on the A1 apparently only outputs a 60i signal. So, two questions: 1. What does this mean for shooting in 24F and 30F? Will an HD field monitor hooked into the analog component not display 24F/30F properly, thus not giving you an accurate WYSIWYG image? 2. If you are tethered to a computer to capture the analog 4:2:2, and shooting in 24F, will the footage be captured by the computer as 60i? How will you be able to edit in 24F? And, two more questions on the analog component: 3. What is the best HD field monitor out there for use with the A1 analog HD component out? 4. Can anyone say (or show!) what advantage HD-SDI has over analog component, both in terms of monitoring and final image quality? I've seen a comparison of HDV vs. analog 4:2:2 coming from the A1, and the difference to me was very small. Apologies if any of this is cross posted or otherwise in the wrong place. |
January 10th, 2007, 11:08 AM | #22 |
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The 30F will sit inside of the analog 1080i stream which means it will look exactly like it was 30F. 24F adds pulldown to sit inside of the 1080i stream so it looks like any other 24p footage that has pulldown added in it such as movies on a DVD being watched on a tube based TV. Since in the real NTSC world we cannot watch a native 24p anyways this is exactly how most of us are used to seeing 24p (outside of a movie theater).
If you want to capture live uncompressed or lightly compressed 24p footage from component you will have to have a tool or software to remove the pulldown from the video. Once you do that you will have true 24p footage to edit with in your NLE. I'm not sure what monitor would give you the best results with component. Your 4th question is a very good question and one that as of yet has not really been answered. Of course one would say that SDI would of course be better because it is digital. Analog is of course analog and can be a little soft and can have a little bit of noise on low quality cables or long distance cables. Does it really show or make a difference? I do not know. All I know is that analog does look very good and will give you very good results with high quality capture devices. I have not captured HD uncompressed but I have captured uncompressed component SD and a DV over firewire and I was very happy with the analog SD. It was a hair softer but it was clean and artifact free and of course 4:2:2 color. While SDI may be better I am not about to complain about only having component on some cameras. Just think a few years ago we didn't have any options at all for uncompressed capture and now we can even do it with consumer HDV cameras. Many of us would have killed for uncompressed component output on a DV camera and now we all have it on every HDV camera. This is a huge thing and shouldn't be looked at lightly. |
January 10th, 2007, 11:36 AM | #23 |
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Visually, there isn't much of a difference between Component and HD-SDI. They are so similar that you will not see a difference upon close inspection of the raw frames, more so after editing and compression for distribution.
But... HD-SDI can be run over long lengths without trouble or degradation (that's the digital part). While Component only stacks up with HD-SDI over short distances. So if you're running from your camera to your computer in one room and the run is only ten feet...your fine. If you're on location and running through the set with a thirty foot cable...you want HD-SDI. In addition, HD-SDI carries your timecode info and audio all in one cable, nice but certainly not necessary in a video quality standpoint. |
January 10th, 2007, 01:07 PM | #24 |
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Thank you, Thomas and Brent. Excellent information that clears many things up.
So IMHO the case for getting the A1 instead of the G1 has been made even stronger. If, as Brent states, analog component 4:2:2 is indeed nearly indistinguishable from HD-SDI, the only advantage (outside TC & audio) is cable length. Anyone out there want to contest this? Regarding cable length, yes it would be quite limiting to have only 10 foot runs of analog cable to work with for some shots (i.e. tracking shots, moving handheld or long takes, etc). But for these shots, since the HDV A1 footage is a *very* close match to the analog 4:2:2 (as I said earlier), difficult shots like these could probably be done simply using the HDV to tape. Anyone think this would be a bad idea, to try to match the HDV to the analog 4:2:2? It increasingly seems to me that the extra $3k for the G1 isn't even close to justified, unless you really need that JackPack. My third question is still wide open: 3. What is the best HD field monitor out there for use with the A1 analog HD component out? |
January 10th, 2007, 02:09 PM | #25 |
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The best field monitor we've found so far is the Panasonic BT-LH1700W. It's got all the inputs -- SD/HD-SDI, SD/HD component analog, NTSC if needed...also includes a basic waveform which is extremely valuable on location. At 1st I was concerned in not using a CRT -- but there really is no HD CRT available for field production. The 1700W's color representation is very accurate, the display is full raster, and there are numerous possibilites for tweaking depending on the gamma setings, etc., you use in-camera in the field. In our main HD post suite we are using the big brother -- the 2600W -- for HD monitoring, while still using a Sony Evergreen SD CRT for critical color correction.
As far as SD vs. Analog -- you can absolutely use longer component analog cable runs than 10 feet! I've run a component post facility since 1992, and am confident that you can have cable runs w/out ANY loss through cable xmission of at least 50ft., and I have done this as long as 80ft. Of course, you need to use high-quality cables & connectors. As stated in above posts, there is a slight softening in the image due to resolving the color info in analog, but nothing to be frightened of. Keith Depending on how you're doing your post, you might consider an HDV to HD-SDI converter, such as those from Convergent or Miranda. |
January 10th, 2007, 03:47 PM | #26 |
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Thanks Keith, that Panny looks very nice.
How do people feel about the Astro Systems monitors, such as the 6" DM-3005? They are much smaller than Keith's Panasonic, but they do have component inputs ("analog YPbPr"). There's also an 8" version (DM-3008), and a 15" version (DM-3015). They also make 6" and 8" Waveform+VectorScope monitors (WM-3004M and WM-3007), which apparently can be used as regular monitors as well. The Astro Systems website shows the 6 inch DM-3005 as supporting the signal inputs below. Does "1920 x 1080 24sF/23.98sF" mean the Canon A1's 24F mode is supported? What is 24sF? 1920 x 1080 60i/59.94i 1920 x 1080 50i 1920 x 1080 25p 1920 x 1080 30sF/29.97sF 1920 x 1080 24sF/23.98sF 1920 x 1080 24p/23.98p 1920 x 1080 30p/29.97p 1920 x 1080 25sF 1920 x 1035 60i/59.94i 1280 x 720 60p/59.94p 1280 x 720 50p 1280 x 720 30p/29.97p 1280 x 720 25p 1280 x 720 24p/23.98p 720 x 487 59.94: 720 x 487/50i |
January 10th, 2007, 05:28 PM | #27 | |
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January 10th, 2007, 05:36 PM | #28 | |
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January 10th, 2007, 05:53 PM | #29 |
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Uh, I see.
Well, money issues aside! - Can anyone comment on the Astro? I am still curious about its feasibility to monitor the A1 as a um, rental... |
March 28th, 2007, 07:27 PM | #30 |
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Component out...again
Im about to buy an A1. My only doubt: what kind of signal comes from the component out?
In the manual says it delivers D3 (1440x1080). What is this? Uncompressed 8 bit high def video? Am i lost? Thanks! Hernan |
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