Image Processing – Scaling Content - AWS Elemental Live

This is version 2.18 of the AWS Elemental Live documentation. This is the latest version. For prior versions, see the Previous Versions section of AWS Elemental Live and AWS Elemental Statmux Documentation.

Image Processing – Scaling Content

Description

Scaling content is typically applied to adjust source content to better match the intended output device screen size or to optimize the resolution of a video output for a particular bitrate. Typically, the lower the bitrate, the smaller the resolution. These settings relate to scaling.

  • Resolution (width, height): Controls the number of pixels encoded (e.g. 1280x720, 640x480)

  • Stretch to Output: Controls the aspect ratio of video content itself. For example, if Stretch to Output is enabled and source content with a resolution of 1280x720 (16:9) is transcoded to 640x480 (4:3), the resulting output video appears skewed as the aspect ratio of the video content is modified.

  • Anti-alias: Choose Bilinear Interpolation or the variable-tap Lanczos filter. In almost all cases, the Lanczos filter provides much better quality when scaling video content, with a small impact on performance.

Recommendations

Enable Anti-alias unless speed is of utmost importance and video quality is not.

Location of Fields

Stream – Video > Resolution stream_assembly/video_description/resolution
Stream – Video > Stretch to output stream_assembly/video_description/stretch_to_output
Stream – Video > Anti-alias stream_assembly/video_description/anti_alias