Gamma and Matrix. at DVinfo.net

Paul Kellett · August 14th, 2008, 12:07 PM

Increasing the Gamma or increasing the Matrix in picture profiles.
What are the effects of each on the picture ?
I'm just a bit confused about what they do.

Thanks.
Paul.

Dominik Seibold · August 14th, 2008, 11:43 PM

Increasing the gamma-level is for example useful for pushing down values to avoid ones above 100IRE. But I'm not sure what mathematical exactly happens.
The matrix-level seems to be a saturation-control after the matrix-multiplication. If it is done in RGB-colorspace (as the main-matrix) the matrix-level could alter the weight of a linear inter(extra)polation between a grayscale- and the identity-matrix which follows the main-matrix in the signal-flow. In YUV-colorspace it would just alter a multiplier of the UV-components, but I guess it's a more efficient way to calculate the product-matrix once and use that.

August 14th, 2008, 12:07 PM	#1
Paul Kellett Trustee Join Date: Nov 2007 Location: Bristol UK Posts: 1,273	Gamma and Matrix. Increasing the Gamma or increasing the Matrix in picture profiles. What are the effects of each on the picture ? I'm just a bit confused about what they do. Thanks. Paul. __________________ Round 2 GH5,FZ2000

August 14th, 2008, 11:43 PM	#2
Dominik Seibold Major Player Join Date: May 2008 Location: Nuremberg, Germany Posts: 285	Increasing the gamma-level is for example useful for pushing down values to avoid ones above 100IRE. But I'm not sure what mathematical exactly happens. The matrix-level seems to be a saturation-control after the matrix-multiplication. If it is done in RGB-colorspace (as the main-matrix) the matrix-level could alter the weight of a linear inter(extra)polation between a grayscale- and the identity-matrix which follows the main-matrix in the signal-flow. In YUV-colorspace it would just alter a multiplier of the UV-components, but I guess it's a more efficient way to calculate the product-matrix once and use that. Last edited by Dominik Seibold; August 15th, 2008 at 12:19 AM.