Video post-processing


The term post-processing is used in the video and film industry for quality-improvement image processing methods used in video playback devices, such as stand-alone DVD-Video players; video playing software; and transcoding software. It is also commonly used in real-time 3D rendering to add additional effects.

Uses in video production

Video post-processing is the process of changing the perceived quality of a video on playback. Image scaling routines such as linear interpolation, bilinear interpolation, or cubic interpolation can for example be performed when increasing the size of images; this involves either subsampling or zooming. This helps reduce or hide image artifacts and flaws in the original film material. Post-processing always involves a trade-off between speed, smoothness and sharpness.
Additionally, post-processing is commonly used in 3D rendering, especially for video games. Instead of rendering 3D objects directly to the display, the scene is first rendered to a buffer in the memory of the video card. Pixel shaders and optionally vertex shaders are then used to apply post-processing filters to the image buffer before displaying it to the screen. Some post-processing effects also require multiple-passes, gamma inputs, vertex manipulation, and depth buffer access. Post-processing allows effects to be used that require awareness of the entire image. Such effects include: