TITRE Adaptive Packet Video Streaming Over IP Networks - LaBRI

original MPEG-4 scene. In MPEG-4, each AVO is coded separately so that the decoding process
decodes also each AVO separately and then the composition module rebuilds the original scene.
We summarize the key results and important components of this system in the following:
• Content-based video classification component: that implements the applicationlevel
audio-visual object classification model. Since the MPEG-4 scene may be
composed of several audio-visual objects (AVO), it is necessary to have a function
that allows distinction between important AVO and less important one. This module
provides automatic and accurate mapping between MPEG-4 application-level QoS
metrics and the underlying QoS-capable network services. Performance evaluation
shows a significant enhancing in network QoS metrics for audio-video streams which
are marked based on the relative priority score of each AVO.
• Video Rate Adaptation component: that implements the fine grained TCP-Friendly
video rate adaptation algorithm. It performs video source rate adaptation to deal with
varying network resource conditions. Based on end-to-end feedback measurements
conveyed by Real Time Transport Control Protocol (RTCP) reports, the video server
adapts its sending rate to much the estimated transmission rate and conforms to it.
This module adapts a fine adjustment of the video rate by adding/dropping AVOs
according to the relative priority score of the AVOs calculated by the Classification
module. Performance evaluation shows a constant visual quality for long-time scale.
• Application level framing component: that implements the robust and adaptive
application level framing protocol with elementary stream multiplexing and unequal
error protection. This module uses RTP protocol for preparing audio-video streams
to be transported over UDP/IP stack. Performance evaluation shows a significant
reduction of the end-to-end transfer delay and the consecutive packet loss of a
particular stream. Even if the error protection augments the traffic throughput of the
original scene, the gain obtained in term of data recovery is better than with error
protection.
• QoS matching component. That could be deployed in video streaming servers or
on edge routers. It offers packet video marking for IP Differentiated Service. We
demonstrate that the interaction and cooperation between application-level (i.e. data
classification model) and network-level (i.e. packet marking) mechanisms can improve
the efficiency of the overall video delivery system. This module receives input from
the classification module, and then it performs dynamic matching between the
application-level RPS (Relative Priority Score) of each video packet and the networklevel
differentiated forwarding mechanism. Performance evaluation shows that
applying an intelligent marking allows to better taking into consideration
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