AVIVA TX9 MPEG-2 toWM9 Real-time Transcoder
Programs for digital cable TV are transmitted in MPEG-2 MPTS format over the satellites. These programs are received with DVB-S satellite receiver, then de-multiplexed, rearranged and re-multiplexed before they are sent over HFC network for broadcast.
On the other side, telecom operators want to provide similar multicast service, with addition of bi-directional on-demand service, over the broadband network. However, since MPEG-2 programs take too much bandwidth (typically 4Mbps for cable broadcast service) for the normal broadband access network, many operators (or ISPs) converts all the video sources into WM9 format to transmit over the Internet. This is because that WM9 is very efficient in compressing video/audio in low bandwidth. Besides, Microsoft’s Media Server platform provides many software tools for creating, playing and managing the media. That helps the operators a lot in setting up the whole video services.
The usual video service on the Internet is On-demand service. Programs are usually produced off-line. There are not many live (multicast) services. Even for those live services, programs are usually pre-recorded or the live satellite programs are decoded into analog format by the satellite receiver and then re-captured into the computer before compression in WM9 format. This process of converting digital media into analog format and re-encoded into digital WM9 format will degrade the video and audio quality.
Aviva’s TX9 is a 1U high transcoder that transcodes in real-time multiple MPEG-2 streams into WM9 streams. MPEG-2 streams are input via the GbE port. TX9 transcodes multiple MPEG-2 streams sinto WM9 streams and then pushes these WM9 streams to the Media Server.The Media Server buffers these real-time streams and unicasts them to the PC and STB clients similar to the multicast service. These live streams are transmitted in unicast streams because many routers in the Internet do not allow multicast packets. Other than the real-time streaming, TX9 can also save these transcoded WM9 packets in a storage device for on-demand service. The top-of the-line model of TX9 can transcode HD MPEG-2 programs into HD WM9 programs.
Tx9 series of transcoders, with different configurations, can support multiple channels of transcoding. The current TX9-1 supports 1 channel of transcoding. TX9-2 supports 2 channels of transcoding. TX9-4 supports 4 channels of transcoding. The upcoming TX9-A model can input the satellite RF signal, de-QPSK quantization, demultiplex MPTS into multiple SPTS, and then selects up to 4 programs to transcode into WM9 format for live multicast or storage. TX9-A integrates the satellite receiver, the IP demultiplexer the save the cost. For higher number of transcoder needs, the dense TX9-X supports 40 channels of transcoding in a 7U high chassis to save space and to easily manage all the channels. Best of all, this model is a carrier-class equipment that supports all the redundancy and hot-pluggability.
