Client-side multisource media streams multiplexing for HbbTV

Hybrid broadcast and broadband TV (HbbTV) provides a unique system to unify various TV delivery systems, from Digital Video Broadcasting (DVB) to Internet Protocol TV (IPTV) and WebTV. We propose to expand such services by multiplexing and tightly synchronising a video stream from IPTV and an audio stream via any Internet Radio station. This would be particularly interesting in content related streams, such as sports events transmitted via multiple channels, whereby a user selects the TV channel from one source and the audio from a separate Internet Radio. Multiplexing media streams at client-side consists of two steps, firstly inserting the new audio stream into the MPEG-2 Transport Stream (MP2T) and secondly synchronising the original video stream within the MP2T with the new audio stream. In this paper we describe the methods employed to insert the audio stream from Internet Radio into the MP2T video stream from an IPTV channel at client-side and we depict the results obtained in the performed testing. The next major challenge is to ensure precise lip-synchronisation (lip-sync) and this is being implemented at present.