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Old 31st October 2010, 04:53   #21  |  Link
Dark Shikari
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Originally Posted by popper View Post
actually DS perhaps you might ask Francois about the SB Decoder ?, i think it will/might, as its not a fixed ASIC fixed-function decoding device such as NV and amd seem to use now, and he could probably work it into the patch if not already there somehow if it ever goes through.
I suspect the SB is more like the most recent iteration of Broadcom's VideoCore; it's not a "pure ASIC", but rather built out of programmable blocks. So, for example, for a motion search, it could load some region of pixels and perform arbitrary checks against it. But that region of pixels still likely has to be 8-bit.
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Old 22nd June 2011, 04:30   #22  |  Link
lovelove
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I come from image editing and I was wondering why did you go from 8 to 10 bit instead of directly to 16 bit?

As far as (still) images are concerned a higher bit depth (16 [or 10] bit compared to 8 bit) is ONLY needed IF 8 bit would result in banding/posterization artefacts. However the price is a bigger file size.

So how do you guys end up saying "10 bit gives better quality at the same bitrate due to greater precision" ??
IMO, the opposite is the case.
10 bit gives marginally better quality (probably only distinguishable for gradients with banding) BUT needs a higher bitrate (due to greater precision).
At the SAME bitrate, I suppose 8 bit would still have better quality.

Last edited by lovelove; 22nd June 2011 at 04:39.
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Old 22nd June 2011, 06:00   #23  |  Link
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I come from image editing and I was wondering why did you go from 8 to 10 bit instead of directly to 16 bit?
Because each extra bit of intermediate precision cuts 50% off the amount of compression lost due to intermediate rounding. After 2 extra bits, you've eliminated 75% of the inefficiency.

Also, 10-bit is the highest bit depth at which luma motion compensation can be implemented without unpacking to 32-bit.

Also, the spec is capped at 14-bit.
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Old 22nd June 2011, 15:58   #24  |  Link
dukey
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What's the point of 10bit video ? Most LCD displays only use 6bit per channel and dither the result. Seems like massive over kill to me. In direct x or opengl, you can render to 16 or 32bit per channel buffers, but the final result is always clamped down for display.
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Old 22nd June 2011, 19:53   #25  |  Link
Dark Shikari
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What's the point of 10bit video ? Most LCD displays only use 6bit per channel and dither the result. Seems like massive over kill to me. In direct x or opengl, you can render to 16 or 32bit per channel buffers, but the final result is always clamped down for display.
10-bit is the intermediate precision. The output precision isn't important.

Audio has used 32-bit intermediate precision (in the form of float) for decades even though the output is only 16-bit.
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Old 22nd June 2011, 20:21   #26  |  Link
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The final version of Libav 0.7 was released. I guess widespread support of 10-bit AVC is underway.
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Old 23rd June 2011, 11:27   #27  |  Link
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Originally Posted by dukey View Post
What's the point of 10bit video ? Most LCD displays only use 6bit per channel and dither the result. Seems like massive over kill to me. In direct x or opengl, you can render to 16 or 32bit per channel buffers, but the final result is always clamped down for display.
You see the Industry has something "new" to bring in for Consumers after the 3D Hype (Ultra Precission Display) UPD for short
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