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-   -   Widescreen 480p? (https://www.dvinfo.net/forum/jvc-gr-hd1u-jy-hd10u/19602-widescreen-480p.html)

Robert Jackson January 10th, 2004 09:35 PM

Widescreen 480p?
 
Something else I've been kind of wondering about is the HD10's 480P mode. That's a native 16:9 mode, too, right? Seems to me that even if you didn't shoot 720p with the HD10 it's still the only camcorder on the market that offers true widescreen progressive-scan Mini-DV, but I haven't seen anyone posting about shooting 480p. Anyone got any comments about that? I assume there'd be no problem at all editing 16:9 480p on most NLE setups.

Troy Lamont January 10th, 2004 10:58 PM

Robert,

I think most people won't use the 480p because of the 720p capabilities. But you are correct on the fact that it's one of the only true 480p camcorders.

I personally will try it out sometime later but I want to advance with the camera in HD mode to learn it's ins and outs first.

If no one replies by the time I test it, I'll give you a heads up.

I do believe that the 480p mode is MPEG2 also with the M2T extension as well. So it would fall under the same constraints that HD editing would.

Troy

Ken Hodson January 10th, 2004 11:03 PM

There are two modes. DV 480p and Mpeg2ts 480p.
The Mpeg2ts mode has a higher pixel count apparently. It is also at 60p, so this makes editing a problem at the moment.
As far as what it brings to the miniDV world, your correct. Although I don't think they are selling to many cams because of it.

Ken

Geoff Pepos January 11th, 2004 02:28 AM

I've done some tests with the 480 60p mode...mainly for slow motion tests. (This is how the varicam does slow mo. It's always shooting 60p...but that's another topic)

I took the (mpeg) 60 progressive frames and slowed it down by half and up res'd it to HD. Think of it as if you are overcranking a film camera at 48fps....here you are taking 60fps and slowing it to 30. There is a thread by David N. about this somewhere around here about how to do it with graph edit and virtual dub...but, the new update to Aspect HD does it for you. Yet I haven't shot any more 60p footage so I haven't tried this out yet with the update.

...very creamy look. It does soften up a bit when upconverting to HD...in the end, it's esthetically pleasing.



As far as editing it, you still need to (well...would want to) convert the mpeg TS to a real editing codec (or uncompressed) in order to edit frame accurately.

That's for the editing section...and I've been clear on which software I find ideal. : )

Jon Fordham January 11th, 2004 11:26 AM

The HD10 does not offer true widescreen progressive scan MiniDV. The 480/60P recording is a different form of compression than the DV25 codec. And thus (to the best of my knowledge), the MP2ts recording does require a unique NLE setup. You can't just plug the HD10's Firewire into FCP and start cutting 480/60P. In fact, I'm unaware of a compatible interface to actually get the 480/60P recording out of the camera digitally. But I'm not well versed in post, so I'll reserve commenting further on editing. Cameras such as the DVX100 which offer 480/30P and 480/24P recording modes are recording the information using the DV25 codec. And even though the DVX100 does actually acquire images in full 480 vertical resolution at a progressive frame rate, the actual recording isn't the same as the 480/60P format. I believe there is only one camcorder that actually acquires and records 480/60P and that is a Panasonic camcorder that was released a couple years ago.

In fact, the HD10 does not offer a true 16/9 widescreen chipset at all. The actual CCD is 1280x960. And every video mode (including the HD mode), crops the CCD to achieve the appropriate aspect ratio. If you switch the camera from still mode to HD mode, you can see the camera cropping the full 960 vertical size of the CCD to 720. The image doesn't get wider, it doesn't continue to use the full vertical resolution of the CCD, it gets cropped.

To the best of my knowledge, there does not currently exist a 16/9 CCD smaller than the 2/3" size. Cameras such as the JVC HD10 or the Sony PDX10 use a standard 4/3 square aspect ratio CCD with plenty of pixel power and then simply sample the area of the CCD they need to achieve the required aspect ratio. If there exists a true 16/9 rectangular CCD smaller than 2/3" currently being used in a camcorder, then I'm unaware of such.

Geoff, one clarification, the HDC27F Varicam does not alway shoot 60P. It always RECORDS 60P. The Varicam will shoot whatever frame rate you choose between 4fps and 60fps. But the tape always records 60fps. This allows you to perform true over-crank/under-crank frame rates and bypass having to digitally fake it in post. The Varicam simply redundantly records the frames when shooting at any frame rate under 60fps. This has the additional benefit of insuring against dropout.

The bottom line on the HD10's 480/60P is exactly what Troy mentioned. If the camera can shoot and record 720P, then why bother with 480P. Especially if you have to find a post workaround for the recording anyway.

Ken Hodson January 11th, 2004 01:08 PM

Jon - "In fact, the HD10 does not offer a true 16/9 widescreen chipset at all."
Technically true. But do we really care what ratio the ccd is? As long as the 16x9 is true pixels, what difference does it make. The ccd could be 5:5, as long as I'm getting a 720p 16x9 image out of it, there is nothing to complain about.

Ken

Jon Fordham January 11th, 2004 03:04 PM

Technical truth is the only thing I'm noting. No complaints.

Though if you want to get into actual pixel count debates, you may want to contact JVC and ask them how they are getting a 1280x720 image when the specifications plainly state that the camera is only utilizing 840K,000 pixels in HD mode.

To achieve a 1:1 "true pixel" ratio for the 720P standard, a device would need to be utilizing 921,600 pixels. At 840,000, JVC is aparently using the same fuzzy math that Canon uses to get 345,600 pixels out of the 250,000 effective pixels on the XL1...

I honestly don't care what aspect ratio the CCD is, Ken. I'm simply noting that Robert's understanding that the HD10 offered true 16x9 480/60P MiniDV was not correct.

Ken Hodson January 11th, 2004 03:33 PM

JVC's documentation is a little goofy. I have seen it spec'ed @ 60p in miniDV mode, and I assumed they ment 30p, when in fact its 60i. I have seen that mode listed as 4:3 and 16x9 as well, but I am now assuming it is cropped to 16x9 in this mode. Not sure though.
How can these big companies not proof read this stuff?

On one of the JVC spec sheets it details the 720p mode as being 1280x659 pixles which works out very close to what they list bellow.

840,000 pixels in HD mode
460,000 in SD mode
340,000 in DV mode

Ken


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