Whoever decided that a television's black-level controls should be called "brightness" and white-level control should be called "contrast" should be raked over hot coals.Zarxrax wrote:I assume when the avisynth manual says that, they mean it in the literal sense of actually changing brightness and contrast. Brightness and contrast adjustments mean very specific things, and are usually NOT what you intend to adjust on your video. Brightness and Contrast are terms that everyone is very familiar with, but few people really understand them.Beefy_Suavo wrote:While I'm busy making a fool of myself...
Maybe include a short explanation for why Levels should be used for adjusting brightness and contrast? The AVIsynth guide for Levels suggests to adjust them using Tweak.EADFAG Beta wrote:Tweak also has some other parameters for things like brightness and contrast, but I strongly recommend against using these. Instead, you should use levels.
http://avisynth.org/index.php?page=Levels wrote:For adjusting brightness or contrast it is better to use Tweak or ColorYUV, because Levels also changes the chroma of the clip.
Let's take Brightness for example. Adjusting the brightness is basically the equivalent of taking a solid white or solid black image and overlaying it on top of your video. It doesn't really make your video "brighter" or "darker" according to what most people's perception's are--it merely makes it "more white" or "more black". A basic "contrast" control has similar problems. By using Levels, we can make the image look more visually darker or lighter, not simply whiter or blacker.
Here are a few links with some more information about levels, hope this helps.
http://www.cambridgeincolour.com/tutorials/levels.htm
http://www.biorust.com/tutorials/detail/198/en/
http://www.poynton.com/notes/brightness_and_contrast/
The resultant confusion and eventual spill-over entrenchment into other display categories makes correcting this error impossible now.