Connecting Tuner Card To Cable Sat
Now that the Myth box is finished, how do I connect it to my Cable, DirectTV, dish or satllite provider? How do I change channels and how does Myth know how to change channels?
There are several ways to connect to your TV provider and HOWTO articles scattered about the internet. This page will not repeat all of that but hopefully tie it all together. The user manual barely touches upon this important subject, I hope someone will link here or get started there.
Several Ways
There are several ways to connect to cable and satellite.
1. Firewire. MythTV supports a Firewire connection to your cable or satellite box, if your box supports it. This configuration is used for HD. Over firewire Myth knows how to change and tune channels. In this configuation you don't even need a tuner card! However you will only get certain channels -- not all. Only the "unencrypted QAM channels". Your cable box or satellite box needs to have a working firewire port.
2. Direct coax. Tuner cards have a coax connector and you plug the coax from the wall directly into the tuner card. The tuner card knows how to change channels and Myth uses an API to the card to request channel changes. If your TV requires a cable or satellite box, you probably will not be able to get all channels directly from the wire. If you use a cable ready TV and you currently plug directly into it from the wall, then this method is all you need.
3. Coax from the STB (Set top box) to the tuner card. This connection means that your STB can unencrypt the signal, and any station you can get on your STB you can get on your card. However, in this siutation, Myth does not know how to change channels on your STB. You need to add an IR blaster device which Myth will use to change the channels on the box. You will probably have to leave your STB box on as well.
4. Svideo/composite/RCA cables from the STB to the tuner card. Like number 3 above. However, you will need an audio in on your tuner card as well as an Svideo in (or composite in). Your STB should already have these output connects for supporting a VCR or other device. In this setup, you will also need an IR blaster and channel change script so that Myth can change the channel on the STB.
How Myth sees these
The Input connections choices in mythtvsetup are shown below. Note that my PVR 250 (MPEG : /dev/video1) has several input connections I can use, including Tuner 1 (coax in) and Svideo 1 and Composite 1.
In the MythTv setup program (mythtvsetup) you define Tuner cards and Input connections. The inputs are the different ways you can connect to your card, such as the coax port (tuner), the composite or svideo port (combined with audio in). On a single card such as the Happpauge PVR 250, you can use both cable in and svideo in, not at the same time though.
Additionaly Myth has you define 'Video Sources' which in the US are connected to Data Direct or Zap2It Labs channel lineups. You can connect each Input source to a different channel lineup.
Below is the configuration page for an input source. After you choose an input connection to define, you can specify the channels associated with the input source and you can optionally tell Myth how to change channels.
If you leave the "External channel change command" box empty, then Myth will tune it using the IVTV driver or API for your card. The exernal command is required when you have a set top box and an IR blaster and you need to call lirc to change the channel on your STB.
Firewire Setup
Firewire is the often the first choice for HD. This is because programs captured over Firewire won't incur a quality loss from having been decoded and reencoded. Cable providers vary in the number of channels that you can receive over the firewire port, normally you can get the local HD broadcast channels and some SD broadcast channels. You will find out when you set it up which channels those are.
You will not need a channel change script if you have one of the MythTV supported boxes, including the Motorolla 6200 and several Scientific Atlanta boxes. However there are scripts and contributions for pefecting the channel change which you can find in the wiki.
In mythtvsetup you will define a tuner card of type Firewire. You can choose from different predefined Set Top Boxes. You should create a separate input input source and video source. In the video source, choose a custom lineup that you edit to include only the unencryped channels you can receive over firewire.
The Wiki FireWire HOWTO covers everything you need to setup firewire. Search for other links as well in the wiki.
It's always good to read some words from Jarod
Coax from the STB
If you have a pvr 250 or similar tuner card, you can run a coax cable from the STB "to TV" output to the coax or 'antenna' input tuner card. You will need to configure Myth to change channels using an IR blaster which controls your set top box. More info on the IR Blaster setup is found here on the wiki.
