[Tig] LUTs for Video File Codecs
Wed May 3 00:22:28 BST 2006
Thanks to oktobor for supporting the TIG
On May 2, 2006, at 22:53, Dan C. Tatut wrote:
> Photoshop has a tool that allows you to preview compressing for web-
> like image formats (e.g. JPEG, GIF). What actually Photoshop does,
> is compressing the image in memory and decompressing it again and
> display the result. This is the preview of the compressed file.
Many compression tools do likewise, but this feature has limited
value when using multi-pass VBR CODECs.
> Another issue is that all the codecs tend to have their own tricks
> to compress images. There is no rule in image compression... that's
> why you have so many available.
> Ideally one should output the media and send it to a compressor,
> decompress it again and compare differences. This can be achieved
> by plugging your color grading system's SDI output into a real-time
> MPEG encoder for example, then plug the output into a real-time
> MPEG decoder and feed-back the color grading system with the
> result. Not so easy but feasible.
Feasible indeed, but probably of zero practical value. Even different
encoders targeting the same CODEC - and for pedantry's sake neither
QuickTime nor Windows Media are CODECs - give wildly differing
results. The best course is to grade as normal and give your
compressionist a solid, consistent target to aim at.
LONDON UK WC2N 4DU
+44 (0) 20 7240 2073
Tig list - http://tig.oktobor.com/mailman/listinfo/tig
TIG wiki: http://tig.colorist.org/wiki
More information about the Tig