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July 17th, 2007, 01:29 AM | #16 | |
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1. Interframe codecs (XDCAM HD) are about 2-3 times as bitrate efficient as intraframe codecs (DVCProHD), so straight numeric comparisons don't show anything other than how much hard drive space is required to store footage! 2. DVCProHD only uses 100Mb/s on 1080i. 3. XDCAM HD has a higher luma resolution than DVCProHD. 4. XDCAM HD has a higher horizontal chroma resolution that DVCProHD. 5. I've never had a problem with an image actually breaking up using 35Mb/s XDCAM HD. 6. Extreme motion is to XDCAM HD what extreme detail is to DVCProHD. You may get softening of the image as the codec runs out of bandwidth. 7. Your own mileage may vary...
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July 17th, 2007, 05:18 AM | #17 | ||||
Barry Wan Kenobi
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July 17th, 2007, 06:18 AM | #18 |
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John,
Thank you very much for sharing your NAB observations. Jan is very accommodating. I'm glad she was able to get you that HPX500 footage. What kind of projects are you shooting with the HPX-500? Thanks again. Greg |
July 17th, 2007, 06:33 AM | #19 | |||
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What I'm saying is that both codecs have limitations. Neither magically capture everything in perfect quality, both make compromises in image quality - just in different areas. Anyway, if intraframe codecs were inherently flawed, then would Panasonic be adopting them on their future products? Yes, acknowledged... being in Europe I forgot about 720p50/60 (no-one broadcasts that over here). Quote:
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Does double the vertical chroma sampling double the image quality? I'd say not. There is actually very little perceptive difference to the colour quality of the images. The eye is about half as sensitive to color "resolution" as brightness. In my opinion the reduction in luma (in the NTSC variants of DVCProHD) has a more significant impact to image quality than the reduction of chroma in XDCAM HD. As to the oft-sited improvements for chromakey work doesn't hold much water too. I have had not found particularly better / cleaner keys from DVCProHD over XDCAM HD when working with progressive footage. There is certainly an advantage to DVCProHD when working with Chromakey work with interlaced footage - but personally that's not something I 'd work with, so I can't comment. (Almost all my work is progressive). Anyway, I'm not arguing about the quality of DVCProHD. It's a great looking codec and I use it almost as much as I use XDCAM HD. What I am arguing with is the idea that XDCAM HD is inferior to DVCProHD simply because it has a lower bitrate.
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