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Trouble with 8-bit uncompressed
Up to now I’ve been quite happy editing in HDV, but I recently started experimenting with 8-bit uncompressed and I’ve run into a few problems. I’m using a 3Ghz Mac Pro with 4Gb RAM and a X1900XT card. I’ve installed a 300Gb Seagate SATA II drive in Bay 2 (not journaled) and I’m capturing all my clips to it and using it as the primary scratch disk. Last night I converted some footage shot on my Sony HC1 to 8-bit uncompressed using HDVxDV. But, when I play the footage back, it stutters and freezes. Surely my Mac is fast enough to handle 8-bit uncompressed? I’ve gone through all my settings and everything seems to fine, but perhaps I’m missing something. Can anyone suggest what I’ve overlooked?
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16 Replies
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….so you realize that 8-bit @ 1080 footage needs about 100 MB/sec sustained transfer rates?
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A single drive is not fast enough for HD. You need at least 150MB/s or so for good playback. The second question is “why?” when HDV support in FCP is very good, and turning HDV to uncompressed does not in any way improve it’s quality.
Graeme
– http://www.nattress.com – Film Effects and Standards Conversion for FCP
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It was just an experiment. I assumed it might lead to an improvement in quality. I’m quite happy with HDV, so I think I’ll stick to that for now. Many thanks for the prompt replies.
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[Graeme Nattress] “The second question is “why?””
Maybe he wants to use G Nicer?
😉
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For 4:2:0 I’d use G Chroma Sharpen though 🙂 And you just need to be on an uncompressed timeline, but you don’t need the source media to be uncompressed.
Graeme
– http://www.nattress.com – Film Effects and Standards Conversion for FCP
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[Graeme Nattress] “you don’t need the source media to be uncompressed.”
True enough, although you essentially end up with just as much disk space being used, since HDV clips on an uncompressed timeline end up getting rendered anyway.
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I keep reading that you should get out of HDV workflow as soon as possible and into 8-bit uncompressed or DVCPRO HD. Is this correct? And, if so, what are the advantages?
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You’ll read that a lot, but:
HDV never gets better than what it is,
HDV support in FCP is very good,
Uncompressed HD takes up a phenonemal amount of disc space
Going to DVCProHD will reduce picture quality, not improve itGraeme
– http://www.nattress.com – Film Effects and Standards Conversion for FCP
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[Ian Wilson] “I keep reading that you should get out of HDV workflow as soon as possible and into 8-bit uncompressed or DVCPRO HD. Is this correct? And, if so, what are the advantages?”
While converting HDV to uncompressed HD won’t get rid of any pre-existing compression artifacts in the footage, working in an uncompressed timeline will avoid any further degradation that might be introduced when layering or compositing clips. Also, any color correction, image filtering or added graphic elements (titles, etc.) will not suffer from compression artifacts. If you have the space and the drive speed, go uncompressed.
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Sure, but you can get the same benefits from just doing afinal render to uncompressed at the end, rather than editing uncompressed. Also, you’d better be mastering to a really good pro HD tape format to see the benefit 🙂
Graeme
– http://www.nattress.com – Film Effects and Standards Conversion for FCP
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