Settings Dialog Box

The Network Settings Tab - Server/Client

Network support is a new feature for DigiTV v3.1. Using this settings box, you can now choose to elect the PC housing the DigiTV hardware to act as a network server to distribute Digital TV on your local area network (LAN). In v3.5 this functionality was further increased to allow you to specify which connected tuners are acting as servers and thus enable you to stream more than one multiplex to a network group if required.

Other PCs on the LAN running the same version of the DigiTV application (without any DigiTV hardware) can then view TV just as if they had the hardware installed. These clients can also optionally control the server so that the channel can be changed.

One of the most versatile features of this networking support is the ability for a DigiTV server to either multicast to all machines on a network or to a single machine.

Because this is a network feature, you should make sure that any firewalls you have installed will allow UDP communication on the addresses and ports that you've specified DigiTV to use.

Note: We strongly recommend that you use a firewall to block communications on these ports on any machine that is used to communicate on a network outside your LAN, eg. a machine that is connected to the internet. This will prevent multicast packets from being routed outside your LAN and likewise prevent DigiTV controlling packets coming in.




This Tuner is ...

  • Standalone - The default mode where no network activity takes place and you can control DigiTV in isolation.

  • A DigiTV Server - The mode that forces DigiTV to act as a server, controlled by the other options in this settings box (only available when DigiTV hardware has been detected).

  • A DigiTV Client - The mode that forces DigiTV to act as a client (only available when no DigiTV hardware has been detected). When DigiTV is set to be a client it will automatically look to see if there are any DigiTV servers serving to the client machine or multicasting on the specified multicast address.

    Once a client connects to a server, DigiTV will automatically obtain the most up to date list of tuned channels from the server. If you try to trigger an autotune on a client machine, this will simply request the tuned list again and therefore you will need to retune the server if you find that there are channels missing.


    Details

    Send Complete Transport Stream - Only available when the tuner is operating in server mode

    Using this option, you can choose to have DigiTV serve the complete transport stream over the network. This means that all TV/Radio/Text channels that are present on a multiplex will be transmitted onto the network adaptor. In the UK this means that the adaptor would have to have a minimum speed of at least 18Mbps in order to provide lossless communication, but because of network overheads this figure should be closer to 24Mbps.

    Most modern 100Mbps will be able to cope with this kind of traffic, but if you are using a wireless adaptor with a quoted speed that lies within this limit (eg 802.11g at 54Mbps), the actual connection speed will vary dramatically due to distance from the base station and occluding obstacles. During our research, we've found that full transport stream over 802.11g is possible, but only over short distances.

    If this option is switched off, then only the data for the current programme is sent, thus dropping the network speed requirement to around 4Mbps. This lies within the range of 802.11b wireless adaptors, but for the reasons just mentioned this will only hold true for short distances.

    Allow Clients to change channels/multiplexes - Only available when the tuner is operating in server mode

    If this option is selected, then any DigiTV client connected to the network will be able to request that the server changes the tuned channel. If the server is only transmitting a single channel then this means that all clients on the network will be affected and will automatically have their channels changed to reflect the new tuning.

    If a complete transport stream is being transmitted, then the server will only change channel if the new request involves a channel hop to a new multiplex, meaning that other clients are unaffected if the new channel happens to be on the same multiplex.

    Deselecting this option prevents any client from being able to change channel/multiplex, in effect giving the server complete control over what clients are viewing.

    Use Multicasting

    Multicasting can be used to transmit the Digital TV data to all PCs on a network. A limited range of IP addresses are used for multicasting and you should select one within this range. DigiTV defaults the multicast address to 230.1.1.1.

    If you prefer to use point-to-point addressing, you don't need to use the Use Multicasting option so please uncheck this. Instead, open up the Server's Networking settings and specify the IP address of the client which is to receive the data. If there is no client available at that address, then the server may appear to become unresponsive.

    Multicast Packet TTL

    Specifies the Time To Live (TTL) for multicast packets to make sure they do not survive beyond the required number of routers or LAN bridges. If there are no jumps to be made across multiple LANs then this value should be set to 1 when using multicasting.


    Control and Data Ports

    These are the UDP ports on which DigiTV implements its network function. All control functions are issued over the Control port and likewise all Digital TV information is sent over the Data port. DigiTV defaults these ports to 2820 and 2821 respectively, but whichever ports you use, they must be allowed by any firewalls present on your network otherwise communication between server and clients will be impossible.