We discuss a problem of optimal design of encoding profiles for adaptive bitrate (ABR) streaming applications.
We show, that under certain conditions and optimization targets, this problem becomes equivalent to the problem of quantization of random variable, which in this case is bandwidth of a communication channel between streaming server and the client. But using such reduction to a known information-theoretic problem, we immediately arrive at class of algorithms for solving this problem optimally. We illustrate effectiveness of our approach by examples of optimal encoding ladders designed for different networks and reproduction devices.
Specific techniques and models utilized in this paper include:
- modeling of SSIM-rate functions for modern video codecs (H.264, HEVC) and different content
- adaptation of SSIM (by using scaling & CSF-filteing) to account for different resolutions and reproduction settins
- SSIM - MOS scale mapping
- CDF models of typical communication networks (wireless, cable, WiFi, etc)
- algorithms for solving quantization problem (Lloyd-Max algorithms, analytic solutions, etc)