[Tig] LUTs for Video File Codecs - carrots

Adrian Thomas adrian
Thu May 4 10:22:11 BST 2006


--
Thanks to oktobor for supporting the TIG
--
Bob, I think you're rather overestimating the kind of precision that  
can be utilised in most lossy CODECs. Frankly, if you got 6bits of  
real data per sample in most cases you'd be doing REALLY well, so  
worrys about losing 10, 12 or 16bit LSBs are a bit much. They only  
real issue is to not allow artifacts to be introduced during  
truncation/resampling that might be regarded by the compressor as  
real image data.
--
Adrian Thomas
Automatic Television
35 Bedfordbury
London WC2N 4DU
www.autotv.co.uk
--


On 4 May 2006, at 03:12, Bob Friesenhahn wrote:

> On Thu, 4 May 2006, Adrian Thomas wrote:
>>> FYI, most encoders can only handle 8-bit per color component.
>>> And often times, you'd rather have your finishing or vfx system  
>>> make the the
>>> bit depth change than an encoding tool.
>>
>> As encoding happens post grade, this is really not an issue. Some  
>> encoders actually offer a dithering function to mask contouring if  
>> required.
>
> Perhaps it is best for the colorist to preview the 8-bit  
> transformation in to ensure that something bad does not happen.   
> For example, two levels may be expected to remain distinct levels  
> but after conversion to 8-bit they become just one level.  This is  
> something not best left to automated dithering.
>
> Bob
> ======================================
> Bob Friesenhahn
> bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/ 
> bfriesen/
> GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/



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