The Holy Grail of video encoding continues to be an optimal balance between perceptual quality and compression efficiency. The quest for achieving a perfect trade-off between the two factors inspires us to find the most effective way for optimal bit allocation for a given video. While traditional multi-pass encoding with fixed bitrate ladder overspends bits for simpler contents, Content Adaptive Encoding (CAE) solutions are emerging as a promising alternative. By allocating only the required bits for a given video, based on its complexity, CAE drives significant bitrate savings.
When choosing the best bitrate for each video, Content Adaptive Encoding takes advantage of the fact that compression effectiveness depends on the content’s complexity. This ensures
- bitrate/bandwidth savings for easy to moderate complexity videos
- and quality improvement for complex video content segments.
This is a method of video encoding in which the encoder adjusts the bitrate of the video on a scene-by-scene basis based on the complexity of the content in each segment. The goal is to maintain a consistent level of visual quality while minimizing the file size of the encoded video.
Below, we list a few crucial factors that contribute to video content complexity –
- Texture Information
- Detailed information in a video: Typically, trees, water bodies, crowds, and outdoor scenes are more complex.
- Sporting events with stadium views, large audiences, grass, gardens, and distant camera views add to high-complexity scenes.
- High Motion and Multiple Motion
- Fast camera movement
- Pan, zoom in, zoom out
- Fast object movement,
- Change in view or perspective,
- Lighting changes, etc., add to the complexity of the video.
- Frequent Scene Changes
- new scenes, change in camera view and adding and deleting objects to the background make the footage more complex.