On Sat, 27 Oct 2007 02:08:26 +0200, David McNab <[EMAIL PROTECTED]>
wrote:
On Wed, 2007-10-03 at 14:10 +0200, Herman Robak wrote:
On Wed, 03 Oct 2007 05:26:54 +0200, Graham Evans
<[EMAIL PROTECTED]> wrote:
If the codec returns uncompressed 4:2:0 or 4:1:1 data, then the
temporary
shouldn't just repeat the colour pixels in a 2x2 or 4x1 pattern. That's
not upsampling!
I was originally repeating chroma pixels myself, then after hearing this
kind of talk on #cinelerra, I tried upsampling the chroma with linear
interpolation. Result? Lots of small border artefacts of strange
colours.
To those who believe pixel duplication is not the way to go, can you
point me to some digestible and specific algorithms (and preferably some
straightforward reference code as well) that gives better upsampling?
Some brief searching around made me aware that although I know something
about chroma subsampling, I knew next to nothing about chroma _upsampling_.
This calls for further research...
These pages looked informative and promising:
http://glennchan.info/articles/technical/chromata/chromata.html
http://ronja.twibright.com/hyperluma.php
http://www.hometheaterhifi.com/volume_8_2/dvd-benchmark-special-report-chroma-bug-4-2001.html
--
Herman Robak
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