Tesis doctoral de Sergio Sanz Rodríguez-escalona
This thesis proposes a rate control (rc) algorithm for h.264/scalable video coding (svc) specially designed for real-time variable bit rate (vbr) applications with buffer constraints. The vbr controller assumes that consecutive pictures within the same scene often exhibit similar degrees of complexity, and aims to prevent unnecessary quantization parameter (qp) fluctuations by allowing for just an incremental variation of qp with respect to that of the previous picture. In order to adapt this idea to h.264/svc, a rate controller is located at each spatial or quality layer so that each rate controller is responsible for determining the proper qp increment. Actually, one of the main contributions of the thesis is a qp increment regression model that is based on gaussian processes. This model has been derived from some observations drawn from a discrete set of representative encoding states. Two real-time application scenarios were simulated to assess the performance of the vbr controller with respect to two well-known rc methods. The experimental results show that our proposal achieves an excellent performance in terms of quality consistency, buffer control, adjustment to the target bit rate, and computational complexity. moreover, unlike typical rc algorithms for svc that only satisfy the hypothetical reference decoder (hrd) constraints for the highest temporal resolution sub-stream of each dependency layer (spatial or coarse grain scalability), the proposed vbr control scheme also delivers compliant sub-streams with lower temporal resolutions. To this end, a novel approach that uses a set of buffers (one per temporal resolution sub-stream) within a dependency layer has been built on top of the rc algorithm. This proposed approach aims to simultaneously control the buffer levels for overflow and underflow prevention, while maximizing the reconstructed video quality of the corresponding sub-streams. This in-layer multi-buffer framework for rate-controlled svc does not require additional dependency layers to deliver different hrd-compliant temporal resolutions for a given video source, thus improving the coding efficiency when compared to typical svc encoder configurations since, for the same target bit rate, less layers are encoded.
Datos académicos de la tesis doctoral «A rate control algorithm for scalable video coding«
- Título de la tesis: A rate control algorithm for scalable video coding
- Autor: Sergio Sanz Rodríguez-escalona
- Universidad: Carlos III de Madrid
- Fecha de lectura de la tesis: 19/09/2011
Dirección y tribunal
- Director de la tesis
- Fernando Díaz De María
- Tribunal
- Presidente del tribunal: Jesús Cid sueiro
- Fernando Pereira (vocal)
- philippe Salembier clairon (vocal)
- José ignacio Ronda prieto (vocal)