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JVC GR-HD1U / JY-HD10U
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Old November 7th, 2003, 01:33 PM   #16
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Christopher - how is the Varicam significantly more compressed than the DVX at 24P? The Variacam uses DVCproHD which is 100mbits/second, rather than DV which is 25mbits/second (even in 24p because it's still recording a 29.97 signal). The Varicam has 3.5 times more pixels resolution than SD NTSC, which would equate to a 28mbits/second data rate equivalent if it were an SD format for the number of pixels pro rata, making it slightly less compressed rather than significantly more.

MPEG2 may be "more efficient", but 19mbits/second is still woefully deficient to record an HD signal with any kind of fidelity. Standard definition DVDs with even more efficient MPEG2 still show artifacts at it's full 9.2mbits/second data rate, yet 720P is nearly 4 times the resolution, yet they're using only twice the data rate.

As for the JVC being close to a CineAlta - I've worked with Panavision and their 24p HDCAM camera, and the footage I've used with Panavision is so far superior to the JVC it's not funny.

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Old November 7th, 2003, 01:35 PM   #17
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Christopher Toderman wrote:
Quote:
Varicam's compression is based on the DV format, while HD10 is using more efficient MPEG2. I'm sure that there will be no situation that the JVC will be equal to the Varicam
That's utter nonsense, Christopher. I suggest you get your facts correct before posting this kind of nonsense.
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Old November 7th, 2003, 02:52 PM   #18
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Don wrote : "but really, we are talking about two completely different classes of camera performance here - one camera that sets the standard for High Definition acquisition and one that wants to set the standard for the consumer HDV format."

You are absolutely right that these are two seperate classes of cameras and I don't think any of us HD10 owners would ever dream that the JVC could out duel the VariCam. We may be optimists but we're not stupid ;)

Still, I for one am interested to see how much is lost from the Varicam to the HD10 because I doubt that you'll lose 90% in quality, which is however the difference in price!

Plus, I think it will provide a simple apples to apples comparison. It will provide a point of reference for us all, so we will no longer have to simply go on the word of others like yourself who have used the more expensive cameras.

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Old November 7th, 2003, 08:29 PM   #19
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Frank Granovski wrote: That's utter nonsense, Christopher. I suggest you get your facts correct before posting this kind of nonsense.

Any technical knowlege or understanding of the technical issues to back up your claim Frank?


Graeme Nattress wrote: Christopher - how is the Varicam significantly more compressed than the DVX at 24P? The Variacam uses DVCproHD which is 100mbits/second, rather than DV which is 25mbits/second.

720p has about 2.25x more pixels than 480p. Varicam records 60p. Going through rate converter 60% frames are eliminated, resulting at 40 Mbps at 24p, vs. 25 Mbps for DV. This makes the Varicam image a lot more compressed.

Because of this low effective transfer rate Varicam is also more compressed than CineAlta, and that include chroma too.

Both CineAlta and Varicam are using compression scheme based on the Sony developed scheme for DV. MPEG2 is more modern and efficient, just as MPEG4 is more efficient than MPEG2.

As I said, any kind of result that would indicate the JVC image would be equal to the Varicam image would have to be questioned as to how the test was conducted. Previous claim on this board that this camera's image is close to CineAlta image is even more outrageous.

Potential for the HDV format? If 3 full resolution CCDs and excellent quality MPEG2 encoding are used, this format can have image equal to that of Varicam. Canon may surprise us here. If Varicam is good enough to make feature films, so may be upcoming HDV Canon. That will mean a true revolution in filmmaking. Whatever this format promises, the JVC unfortunately misses.
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Old November 7th, 2003, 08:39 PM   #20
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Christopher T.,

Anything you'd like to see specifically tested? I'll email my friend.

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Old November 7th, 2003, 09:33 PM   #21
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HDV has a great potential. HDTV broadcasts are mostly 1080i at 19 Mbps, encoded in MPEG2. 1080i HDV is 25 Mbps. Because of the digital transparency, HDV is all that will be needed to produce HDTV content. I already covered HDV quality potential in comparison to Varicam. Another factor is that the upcoming revolution of digital projection will make give additional edge to digital, vs. film.

The biggest factor here is that HDV is an open format. HDV recorder, less the MPEG stuff is an HDV recorder. They are digital and will be equal. This craetes an opportunity for other companies to enter the HDV pro market. HD will no longer be conntoled by Sony and Panasonic, who may be fearful of quality HDV competition. The JVC is built with too many limitations probably of this fear, as JVC is owned by Matsushita, maker of the Panasonic label.

I think that Canon will be the first to come out with a superb HDV camcorder that will be usable for filming, and will naturally have a new line of interchangable lenses. P+S Technik may be working with Canon right now on their adaptor. So affordable filmmaking is around the corner.

Ikegami has been using both Sony and Panasonic SD recorders with their camera heads. Thompson makes pro HD cameras -- Viper, etc., and consumer DV. Samsung must have been eying the pro market for some time. They certainly have as much capability to produce quality stuff tht is comparable to top Japanese firms. Sharp is heavy into HDTV flat-screen sets. So all these firms are potential producers of high quality HD cameras.

Sony and Matsushita are very aware of the competiton HDV will bring to their SD and Varicam equipment. The death of SD is very near. There is no way Sony will be able to sell $40K cameras if a fraction costing Canon camera will be better. I'm sure that Panasonic will be coming out with a lot better camera than Varicam. They see the writing on the wall.

There will be pressure on Sony and Matsushita to make their HDV cameras better than the upcoming cameras of Canon, Ikeagmi, Hitachi, Sharp, Samsung, and Thmpson. The next couple NABs will be very interesting and will probably mean a start of an era when a highschool student will be able to win an Oscar, with a $100 budget documentary, using dad's HDV camcorder.

HD Blu-ray DVD recorders are held in their introduction mainly because of Hollywood'd copyright threats. But there is no threat to blu-ray HDV camcorders. This too is an open format. Unfortunately it was developed by Sony and Matsushita is a part of the consortium. So again we may see an attempt to keep the format from competing with CinaAlta, etc. However Blu-ray camcorders will be available soon; the recorders have been selling in Japan for some time already.

With the introduction of blue laser there will be other recording format and it will not take long for Toshiba or Pioneer to make available a burner with 100 Mbps or higher transfer rate. Now we are talking about CineAlta level of qulaity, and with a quality MPEG processor even higher quality. If Samsung ads a good qulity head to this, we may see CinaAlta quality at a very small price.

By that time Sony and Panasonic will be promoting uncompressed formats for filmmaking. But you and I will be able to own a camera with similar quality that Lucas and Rodriguez made their blockbuster and near blockbuster films with.
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Old November 7th, 2003, 09:40 PM   #22
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I have first impressions from Jon. I'll post up in another thread later.

heath

ps-He'll write a full review on Tuesday once he gets the VariCam footage downconverted.
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Old November 7th, 2003, 09:41 PM   #23
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Heath, can you do same shots outdoors in direct sunlight, in a shadow, in a studio, with a vareity of contrast, at normal, low, and very low lighting, also slow panning shots. Colorful set too would be helpful.

Could someone with DVX loan this to Heath so we may have a good reference point where the JVC is in comparison? DVX should be tested in progressive, 30p, 4:3 aspect ratio, as no good anamorphic adaptors exist.
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Old November 7th, 2003, 11:44 PM   #24
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This is my friend shooting, not me, in NYC.

He's using his DVX100 in two weeks with the HD10, but NO Varicam, sorry.

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Old November 8th, 2003, 05:24 AM   #25
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Christopher wrote: "720p has about 2.25x more pixels than 480p. Varicam records 60p. Going through rate converter 60% frames are eliminated, resulting at 40 Mbps at 24p, vs. 25 Mbps for DV. This makes the Varicam image a lot more compressed."

But in your earlier post you wanted to compare both cameras as 24p. If the Varicam records at 60p and just records 24 frames in that interval thus wasting 60%, then the DVX at 24p is wasting 12 fields out of 60 fields (DVX being a 60i camera?)? Giving an effective data rate of 20Mbps for the DVX?

Let's check my maths again - I'll write out the steps to see what's going on.
720P is 720 * 1280 pixels? = 921600
480P is 480 * 720 pixels? = 345600

921600/345600 = 2.66 - this is different from the number I said earlier which was way off, and the number you quoted earlier too? Any ideas?

Varicam is 40Mbps for 2.66 times as many pixels as DVX, which would give it 15Mbps compared to 20Mbps for the DVX at 24p from above pro rata.

Ok - it's signifantly more compressed - how funny is that? Thanks for helping me with that one Christopher!

But - is Varicam 4:2:2 or 4:1:1 like DV? If so that would change the figures, would it not?

I agree that MPEG2 has greater efficiency, but the version being used is a delivery codec rather than a production/acquisition codec. Even if it's the same data rate as HDTV broadcasts then that's no indication of quality due to HDTV looking a bit crap and artifacty.
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Old November 8th, 2003, 06:27 AM   #26
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I thought that the DVX records at 25 Mbps even at 24p. If that is the case then it is less compressed in both luma and chroma. If it is 20 Mbps, which I don't believe is the case, then it is overall less compressed than the Varicam, but the Varicam, having 4:2:2 sampling would be less compressed in chroma, more in luma than DVX, but overall more compressed. Although Varicam is 4:2:2 and CineAlta approx. 3:1:1, it is less compressed than Varicam in both luma and chroma. So the calam that 4:2:2 means better colors is meaningless at 40 Mbps.

The MPEG processing on the JVC is crappy but future camears could have quality processors and then we are on the Varicam picture quality level.
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Old November 8th, 2003, 07:40 AM   #27
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Christopher - by your argument that 24p on the 60p Varicam that although it's recording 24 frames per second, it is really recording 60 frames per second, and many of them are the same, and hence redundant. The camera does not take this redundancy into account and still records 60 discrete frames per second, and hence gives no data rate advantage to 24p recording? Is this so - I think it is from what I've read?

Then the same replies to the DV format DVX which records 24 frames per second, yet the frame rate stays at 60i, hence by the argument above for the Varicam, is the equivalent of 12 fields redundancy, which equates to 20% of the data rate being wasted, unlike, as you pointed out on the Varicam where it's a massive 60% wasted.

Looking at the numbers again taking colour sampling into account:

DV = 25Mbps for (720 * 480) * (1 + 1/4 + 1/4) = 518400 pixels per frame

Varicam = 100Mbps for (1280 * 720) * (1 + 1/2 + 1/2) = 1843200 pixels per frame

which means that the varicam is spreading its data over 3.55 as many pixels (including colour and luminance)

which gives:

DV 30fps = 0.83Mbpframe
Varicam 60fps = 1.66Mbpframe = 0.46Mbp DV sized frame - almost half the effective data rate.

Doing the figures at 24p gives the same results as the calculations above are per frame. So taking into account the colour sampling makes matters worse, not better.... This has turned out to be very interesting. Thanks.
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Old November 8th, 2003, 08:52 AM   #28
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Grtaeme, the recorded stream is 100 Mbps on Varicam and then the rate converter discards 60% frames when it transfers the 60p to 24p so the effective rate at 24p is 40 Mbps. DVX records in 30p or 24p in progressive and the bit stream is 25 Mbps at either speed. It does not record 60i in the progressive mode. Varicam samples chroma twice as many times as 4:1:1 format, but the pixel count is 480x720 and 720x1280.
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Old November 8th, 2003, 09:24 AM   #29
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Christopher - the DVX records at 25Mbps all the time, but when you take it into CinemaTools to extract the 24p the resulting data rate of the 24fps file is 20Mbps. In All modes it records a 60i signal that "looks" like it's 24p or 30p (in 30p there is no temporal difference between the fields, but it's still a 60i standard DV signal, and in 24p the 24 frames get spread out over the 60 fields using 3:2 or 2:3:3:2 ? pulldown).

You are still correct - the VariCam is more compressed than DV - and I find that very funny!
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Old November 8th, 2003, 09:40 AM   #30
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The VariCam records 1280 x 720 x 60P in 100mbits.

That's 552,960 pixels per megabit.

The JVC records 1280 x 720 x 30P in 19mbits.

That's 1,455,158 pixels per megabit (about 3x as compressed as the VariCam).

Standard-def DV records 720 x 480 x 60i in 25mbits.

That's 414,720 pixels per megabit.

Any talk of the frame-rate converter and discarding frames, etc is just confusing the argument, and completely irrelevant. The VariCam, and the DVX, record fixed frame sizes at a constant bit rate and constant data rate, whether shooting 24P, 30P, 60i, or (on the VariCam) any other frame rate.

So the VariCam is slightly more compressed than DV, but much, much less than the JVC. Those are the simple facts, but the notion or concept that this means anything, is simply absurd. The VariCam picture is EXTREMELY much better than the JVC or DV, and it doesn't really matter how you get there or what the compression format is or whatever, so what is the point of this discussion?
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