Simulcasting IPTV and RF QAM Streams
The new encoder can simulcast both a QAM HD cable channel and an IPTV stream. This is possible because a QAM channel carries an MPEG2 Transport Stream. An HDTV tuner tunes in to the channel and passes the stream to the TV’s internal decoder. It’s the same encode/decode process as IPTV, but using RF as a carrier instead of Ethernet. Once the stream is created, it can be passed on to a QAM processor for RF, and/or the IP port for IPTV distribution.
We use the popular term “2-channel operation” rather than get too technical in everyday discussions. What’s actually happening is there is one Transport Stream that can carry up to two separate Programs, which is why you often see digital channels shown as 2.1 and 2.1 and so on.
The QMOD can be set to distribute the stream over RF only, IPTV only, or both. It’s the same stream, either way.
The total bandwidth of the stream can be up to 38.4 Mbps, composed of two 19.2 Mbps programs. The bitrate of each program can be set to 10-25 Mbps, in half-steps, so the total bandwidth can be less, but quality goes down with bitrate.
The IPTV stream can be set for Unicast or Multicast modes. In Unicast, the QMOD’s own IP and port is defined, as well as the receiver’s address and port. Only one Unicast relationship can be defined at present. Set to Multicast, many network decoders or players such as VLC can view the video. Without getting too technical, the site’s network must be setup for this activity, especially for Multicast.
To “tune in” a player will enter the UDP address set up in the QMOD, typically UDP://@239.xxx.xxx.xxx:port #. Our default setting starts with 239, but that can be changed.
Once you connect with VLC software, it will allow you to select Program 1 or 2, other players use a similar process.
The next step will be to add MPEG-4/H.264 to the mix. That will enable more options for IPTV distribution, and selected models (not all) of Smart TVs can receive MPEG-4 QAM channels over RF. Other standards are likely to evolve for RF and IPTV in the future, and architecture of our new QMOD encoder can integrate those standards as well.