Difference between revisions of "Fm radio"

Revision as of 22:19, 9 October 2007

This article is to provide information on how to integrate FM radio into MythTV. This is based on Integrate Sirius but I wanted to post details on how to make it work for FM radio too.

I only have a Hauppage PVR-150 card. I cannot speak to other setups, but please feel free to edit this page to include information for others.

Article from 10,000 feet

What this article is...

This article IS about:

• Setting up MythTV to play FM Radio from a Hauppage Wintv PVR-150
• How-To use programs that other people wrote (and are not affiliated with MythTV)
• How-To integrate everything with the default MythTV menu theme

What this article is not...

This article IS NOT:

• How-To perfectly integrate with your particular MythTV GUI (we only cover the default menu theme)
• An FM Radio Plug-in for MythTV
• An audio stream capture how-to

What is required

Only a working installation of MythTV is required with a working PVR-150. Also you must be able to receive and play an FM signal on your PVR-150. To verify this do the following:

# ivtv-radio -s

This will scan the FM band for channels. Next do the following:

# ivtv-radio -f <frequency of channel>

for example:

# ivtv-radio -f 103.3

if this does not work, please see the [web page] for detail on how to make this work and return here when you have this working.

Hacking it together

OK, now we are going to write a couple of über-simple shell scripts that we will use to make MythTV work with your FM tuner. You will notice that these are simple, novice scripts that are pretty crude. This hasn't been called it a "hack" for nothing.

Create files

We need to create a couple of files so find a nice place you can create and execute them from. Personally, I put them in /usr/bin

# vi mythfm

#!/bin/bash
# Control PVR-150 FM in Myth

if [ "$1" = "wbfo" ]; then
        # First, we'll kill off any other stream that may be playing
        /usr/bin/mythfm_kill
        echo "I'm about to play:" $1
        /usr/local/bin/ivtv-radio -f 88.7 &

elif [ "$1" = "wbuf" ]; then
        # First, we'll kill off any other stream that may be playing
        /usr/bin/mythfm_kill
        echo "I'm about to play:" $1
        /usr/local/bin/ivtv-radio -f 92.9 &

else
        exit 1
fi
exit 0

You are going to want to change this for the stations you want. Add more "elif" statements to add more stations. Change the first line of each statement to include the callsign of the station and change the last line of each to add the station's FM frequency.

# vi mythfm_kill

#!/bin/bash
# Kill mythfm

pkill -f aplay

Now you will want to make them both executable:

# chmod a+x mythfm*

Test scripts

Now, pull up a command window and run one of the commands we just "made"

$ mythfm wbfo

Do you hear the stataion without having to enter a single thing in the command window? That's good, now use this to kill the stream

$ mythfm_kill

V4L-Based Radios

The following combined tune/kill script uses a more general approach that works for v4l-based radio devices. The basic idea here is that we first configure the tuner for the station we want, then capture from the radio device and forward to the output device. This method requires that you have fmtools and sox installed. For this to work you must also have alsa-oss support working. This can also be done with pure alsa (look at the sox manpage) but using oss was easier for me to get working. Save the following script to /usr/local/bin/mythfm then replace calls to "mythfm_kill" in the menus created below with "mythfm kill". It should be fairly obvious how to add stations to this script and add them to the menus.

-- work(dot)eric(at)gmail(dot)com

#!/bin/bash

# tune radio
function fmtune {
  fm -q -T- $1 on > /dev/null &
  sleep 1
  sox -q -r 32000 -w -c 2 -t ossdsp /dev/audio1 \
         -r 44100 -w -c 2 -t ossdsp /dev/audio &
}

# kill radio
function fmkill {
  killall -q /usr/bin/sox
  sleep 1
  killall -q /usr/bin/fm
}

# Station: Jack FM (93.1 MHz)
if [ "$1" = "jack" ] ; then
  echo "Tuning to Jack FM"
  fmkill ; sleep 1 ; fmtune 93.1

# Station: Star (98.7 MHz)
elif [ "$1" = "star" ] ; then
  echo "Tuning to Star"
  fmkill ; sleep 1 ; fmtune 98.7

# Station: Kill Radio
elif [ "$1" = "kill" ] ; then
  echo "Turning Off Radio"
  fmkill ; sleep 1 ; fm -q off &

else

  # print usage statement
  echo "Usage:" `basename $0` "[station]"
  echo "  stations: jack star kill"
  exit 1

fi

exit 0

Setting up the MythTV GUI

At this point, you should be able to listen to (and kill) streams from the command line with no user intervention... that's 1/2 the battle. Now, we are going to hack a couple of buttons onto the default menu theme.

Backup the default theme

# cd /usr/share/mythtv
# tar cfvz default_backup.tar.gz *.xml

I use the v option because it's an easy way to verify (VIA verbose) what files were put into the tar ball.

Hack the default theme

I'm only going to show you the 2 required changes to get this hack to work.

I added the following to my mainmenu.xml file.

# cd /usr/share/mythtv
# vi mainmenu.xml

   <button>
      <type>MUSIC</type>
      <text>Play Radio</text>
      <action>MENU fmmenu.xml</action>
   </button>

Then, I created the fmmenu.xml file (be sure to add all of the stations you want access to):

# vi fmmenu.xml

<mythmenu name="FMMENU">

   <button>
      <type>MUSIC</type>
      <text>88.7 - WBFO - NPR</text>
      <action>EXEC /usr/bin/mythfm wbfo</action>
   </button>

   <button>
      <type>MUSIC</type>
      <text>92.9 - WBUF - Jack FM</text>
      <action>EXEC /usr/bin/mythfm wbuf</action>
   </button>

   <button>
      <type>TV_DELETE</type>
      <text>Stop Listening</text>
      <action>EXEC /usr/bin/mythfm_kill</action>
   </button>

</mythmenu>

Tag definitions

OK, now the tag definitions for the above xml file

• "button" tells the theme to paint a button on the screen
• "type" tells the theme what image to use for the button
• "text" tells MythTV what button text to put on the screen
• "action" tells MythTV what to do when you select the button

Why it works

You have to wrap mythfm around the stream because when MythTV runs the EXEC it waits for a response before it releases the button. mythfm simply kicks off ivtv-radio and tells MythTV that it's finished executing. You are going to have to modify this file if you want to add another language tag or if you want to add additional channels, it should be simple to see what needs done to make it work just be sure that you create the soft links before you try to add a button or it won't play the stream.

Additional Setup and Usage Notes

1. The stream will play until you choose the "Stop Listening" button on the GUI (or the mythtv_kill script is executed)
2. When you're listening to a station, it locks up the Video Card device for MythTV which. This means that you are using up one of your 'inputs' for video recording or watching TV. You must have more tuner cards in order to listen to FM on a PVR-150 and watch video at the same time.
3. With MythDora 4.0 ivtv-radio is in /usr/bin. Modify scripts accordingly.
4. If you have 2 PVR-150s then the radio may be on /dev/radio1. If so, add -d /dev/radio1 to the ivtv-radio lines. If the radio is at /dev/radio1 then the PCM device to use is /dev/video25. Add -i /dev/video25 to use this PCM device.

Screen shots

The new default main menu:

The FM station selection menu: