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Old September 3rd, 2004, 08:45 PM   #1
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XL2 vs HD10 16:9 resolution

Why when in SD mode does the XL2 offer 960x480 while the HD10 offer just 720x480? They are both 16x9 SD so why the difference?
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Old September 4th, 2004, 07:43 AM   #2
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I would highly recommend using the HD mode on the HD10, because Lumiere HD doesn't support SD and the HD mode is 1280x720p.

I shot something in SD mode, since it was for SD broadcast, and it was a NIGHTMARE getting the thing to transfer to DV...

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Old September 4th, 2004, 08:30 AM   #3
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My understanding is that all 16:9 SD footage recorded to DV tape is 720X480, with non-square pixels. That is also what is on a 16:9 video DVD.

However ... the sensor area used to record the image varies among different makes and models of camera. Indeed with my Sony TRV70 the pixel area used actually changes as the camera zooms(!). An electronic interpolation process is then applied that converts the raw data to 720X480 - the argument being that the more pixels used the better, as it will provide better input for the interpolation.

That said, I am not up to speed with the XL2 specifically, and the 3-chip issue makes pixel counts a bit murky, so I will be interested to see how others respond to your question.

And as an aside, the marketers for Sony, Canon et al. should be whacked around the head with a brick for their completely hopeless and often misleading explanations of the 16:9 features of their various camcorders. In 2004, 16:9 capability is (or should be) a key consideration for anyone buying a camcorder, yet it can be a major effort to find reliable information on what process many of the consumer cameras are using to generate their 16:9.
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Old September 4th, 2004, 12:04 PM   #4
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The patch of the CCD that the Canon uses has a grid of 960 x 720 pixels. However, that gets sampled and digitized into a pixel array of 720 x 480 for recording on tape.

It's not much different from how other megapixel cameras work: they may have 2 million pixels on the CCD, but when it gets turned into DV video it's 720 x 480.
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Old September 4th, 2004, 01:01 PM   #5
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Barry, that is sort of what I thought but the Canon data sheet says this:
16:9 460,000 pixels 962x480
4:3 350,000 pixels 720x480

Notice the vertical resolution does not change (480)

JVC lists the 60p SD mode of the HD10 as 460,000 pixels 720x480
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Old September 4th, 2004, 03:05 PM   #6
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There are pixels and then there are pixels.

Let's see, how to do this. Ity is like the lines of resolution for the camera don't really have the same meaning as the lines of resolution on the tape.

Pixels. There are pixels on the CCD. In a given format of image such as SD on an HD10, the image is shown on the CCD and covers a set number of pixels, let's say 950 in each row with 480 rows. In round numbers I think this is about 460k. This is on the CCD and that is really where it may stay. It doesn't have to be related to anything else in the camcorder since it is always A/D converted. Sooner in some cameras then others.

The A/D happens as each row is shifted out horizontally with each pixel's value being held in a sample and hold register for about 1/950th of the line "timing" to cover over the no charge domain shift register area between each pixel where no image is detected.

For NTSC video (read Standard Def) the line must be dealt with as 720 pixels. SO there is a sample clock running at 1/720th of the lines timing that "clocks the A/D conversion of the contents of the sample and hold register.

These two things are separate. The 1/950th clock shifting into the sample and hold and the 1/720th clock "reading" the same sample and hold.

So this gives the 720x480 which is both 4:3 and 16"9 NTSC.

Certainly we can construct a scenerio where this will miss a piece of image detail, but on the whole we do in fact get more information about the image by using 950 pixels to start with.
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Old September 4th, 2004, 04:11 PM   #7
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>>>>>>It's not much different from how other megapixel cameras work: they may have 2 million pixels on the CCD, but when it gets turned into DV video it's 720 x 480.
--------------------------------------

A major difference in how 16:9 is generated in consumer camcorders is between the models that use greater than 720 pixel in width and "shrink in" to reach 720, versus the ones that stick to a 720 wide pixel patch, cut off the top and bottom rows of pixel data to get to 16:9, and then "stretch up/down" to get back to 480. The latter method produces the correct aspect ration, but at the cost of significantly reduced vertical resolution.

An easy way to distinguish the two methods is to check whether the camera's wideangle gets wider when switched from 4:3 to 16:9. For example, the Sony PC100 doesnt but the Sony TRV70 does.

I'm not aware that ANY consumer camcorders with 2+ megapixels actually use all their pixels when in video mode.
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