Accessing Colour Grading Menus			Control Surfaces
Chapter 12, Colour Grading: Basics

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GPU Auto Switch

GPU Compatibility

Processing with the Graphics Processing Unit (GPU) is available for certain features and is faster than processing with the Central Processing Unit (CPU).

Support for GPU acceleration depends on the version of the NVIDIA graphic card that is installed on your system. The following configurations are supported for GPU acceleration.

GPU acceleration is available for the following features:

• 1D or 3D on calibration LUTs

• Animated or still repositions (including rotations)

• Animated or still input primary grading

• Input and output primary grading with RGB, hue and light saturation (LS) curves

• Secondary grading with RGB curves

• Secondary grading with hue curves

• Secondary black clip/reference and white clip/reference in Linear mode

• Secondary key cleanup and shrink

• Imported mattes for secondaries

• Gamma and contrast adjustments to secondaries in Linear mode

• Low, mid, and high adjustments to secondaries

• Input and render/output LUT

• Lustre Sparks plugins

  • Blur mix

  • Glow

  • Noise plugin 3.1

  • Printbleach

  Note: A performance hit can occur when using the Lustre Sparks plugins.

For more information about these features, see:

• Chapter 13, Primary Colour Grading

• Chapter 14, Colour Grading: RGB and Hue Curves

• Chapter 16, Creating Lustre Sparks Effects

GPU acceleration is also available for certain secondary grading features with up to 12 layers enabled. You can apply, and optionally animate, each of the following secondary grading features and continue to use GPU acceleration:

• Primary grading inside and outside geometries, including adjustments to overall brightness, contrast, hue, and saturation

• Softness, Color, and Opacity slider values for geometries, with Softer and Variable optionally enabled

• Key-in shapes based on hue, value (luminance), and saturation, and refined by tolerance and softness range definition

• Key and geometry blurs

  Note: A performance hit can occur when using the geometry blur.

• Multiple point changes for geometries

For more information about these features, see Chapter 15, Secondary Colour Grading.

When GPU acceleration is enabled, the histogram, vectorscope, and waveform monitors do not dynamically update. They retain the colour distribution of the image before GPU was enabled.

The following parameters cannot be accelerated by the GPU. These parameters are processed by the CPU instead:

• Lustre Sparks plugins

  • Add noise

  • Blur

  • Defocus

  • Directional blur

  • Field zoom

  • Gold

  • Noise plugin 2

  • Noise plugin 3

  • Silver

Note: If GPU acceleration is enabled and Lustre encounters a shot with features that cannot be processed by the GPU, the CPU is used for the shot. The GPU button remains enabled, but is greyed out until you navigate to the next shot in the timeline that contains features available for GPU acceleration.

• Complete one of the following:

  • Click GPU

  • Press Y

  

  A GPU flag appears in the upper-right section of the Player.

  

  Note: GPU acceleration only works in progressive scan mode. Before you render a project, you need to switch the scan type to interlaced (located in the Setup > Grade menu).

• Complete one of the following:

  • Click GPU

  • Press Shift+Y

  GPU acceleration is disabled.

GPU Auto Switch

By default, when you use a feature that is not supported by GPU (while in GPU acceleration mode) it automatically switches to CPU processing mode. The GPU button is greyed out in the user interface to show you that this feature is not GPU compatible. You can prevent the switch to CPU mode by disabling the GPU Auto Switch feature, see Display & Interface Settings. When you disable the GPU Auto Switch button, you can only see features which are supported by GPU (when GPU acceleration is enabled). To see all of the features, you have to disable the GPU button.

GPU Compatibility

Key blurs and geometry blurs are processed differently depending on whether CPU processing or GPU acceleration is enabled. To ensure that they are always displayed identically, enable the GPU Compatibility (GC) button before you start work on keys, key blurs, and geometry blurs. The GPU compatibility feature is automatically enabled when GPU acceleration is enabled.

You can also enable the GPU compatibility feature when you set your user settings. See, Display & Interface Settings.

Note: Enabling the GPU compatibility feature does not impact final renders, nor does it jeopardize preview performance. It ensures that GPU acceleration is performed in such a way as to closely match how keys, key blurs, and geometry blurs are displayed in CPU grading mode.