Media synchronization at network context minimizes the effects of the network jitter and the skew between the emitter and receiver clocks. Theoretical algorithms cannot always be implemented on real
systems for the architecture differences between a real and a theoretical system. In this paper an implementation for an intra-medium and an inter-media synchronization algorithm for a real multistandard IP set-top box is presented. For intra-medium synchronization, the proposed technique is based on controlling the receiver buffer. However for inter-media synchronization, the proposed technique is based on controlling the video playback according the Presentation Time Stamp (PTS) of the media units
(audio and video). The proposed synchronizations algorithms has been integrated in an IP-STB and tested in a real environment using DVD movies and TV channels with excellent results. Those results show that
the proposed algorithm can achieve media synchronization and meet the requirements of perceived quality of service (P-QoS).
Internet Protocol Set-Top Boxes (IP STBs) based on single-processor architectures have been recently introduced in the
market. In this paper, the implementation of an MPEG-4 SP/ASP video decoder for a multi-format IP STB based on a
TMS320DM641 DSP is presented. An initial decoder for PC platform was fully tested and ported to the DSP. Using this
code an optimization process was started achieving a 90% speedup. This process allows real-time MPEG-4 SP/ASP
decoding. The MPEG-4 decoder has been integrated in an IP STB and tested in a real environment using DVD movies
and TV channels with excellent results.