[mythtv-users] Easier analog channels for pcHDTV 3000 (and 5500) owners

Kevin Bailey ke-myth at retriever.dyndns.org
Fri Mar 7 15:41:03 UTC 2008


In case you didn't know (I didn't until recently), the
HD3000 and HD5500 can receive analog signals without
messing with that hoaky "connect the tuner to your line-in
port" kludge that pcHDTV suggests.

The chip on these cards has a built-in A2D converter that
can DMA to main memory. What this means is, you can get the
analog signals over a plain, vanilla V4L interface -
/dev/video* and /dev/dsp*.

Here are the steps that I went through to get it to work.
I have a 2.6.20 kernel and myth 0.20.2 (Ubuntu Feisty).

1. See if your tuner card has the audio port enabled:

lspci | grep -i 'audio port'

If yes, skip to 10.

2. If not, download utility to enable audio port.

wget http://www.speakeasy.org/~xyzzy/download/cx88_eeprom
wget http://www.speakeasy.org/~xyzzy/download/pchdtv_audio

3. Make them executable

chmod +x cx88_eeprom pchdtv_audio

4. Make sure i2c-dev is loaded.

lsmod | grep i2c-dev

If yes, skip to step 6

5. Load i2c-dev

sudo modprobe i2c-dev

6. Run the script

sudo ./pchdtv_audio

If it succeeded, skip to 8.

7. If not, run the utility manually

If the script failed like this:

Found CX88 Card 0 on I2C bus 2
Unable to open file /sys/class/i2c-dev/i2c-2/device/subsystem_vendor: No
such file or directory at ./pchdtv_audio line 27.

then just run cx88_eeprom manually. Copy the bus number from above
(in this case "2" (from "bus 2")) to the end of this line (replace the
(second) "2" in "i2c-2".)

sudo ./cx88_eeprom /dev/i2c-2

If *that* doesn't succeed, I don't know what to say
except you probably shouldn't proceed. As I understand
things, pcHDTV will happily exchange the tuner for one
with the audio port enabled.

8. Reboot

9. Make sure the audio port is enabled.

lspci | grep -i 'audio port'

10. Make sure cx88-alsa is loaded.

lspci | grep cx88_alsa

If yes, skip to 12. Mine was loaded automatically.

11. If not, load cx88-alsa

sudo modprobe cx88-alsa

12. Find your new interface.

ls /dev/dsp*

There should be a new either /dev/dsp1 or /dev/dsp2
(or something else ?). Remember its name.

13. Start up mythtv-setup

14. Go to Capture cards

15. Select your pcHDTV card.

16. Enable the analog half

Assuming that your card type is DVB, there should be
a button in the middle that says something like
"analog" or "video4linux" (I forget). Select it.

In the next screen, change where it says "/dev/dsp"
to the new /dev/dsp* that you found above.

IIRC, this is also one of the places that you need
to change the audio sampling rate to 48000.

11. Exit and go to 'Sources'

12. Add a source called 'Analog' (or whatever you like)

I did NOT assign a scanner to mine, even though I have
Schedules Direct. Re-using my existing Source did not work.

Theoretically, you can create a second account to assign
to your analog signal but I can't confirm this.

13. Exit and go to Inputs (?)

You should now see 4 inputs where you used to see 1
(more if you have more tuners). The new ones should be:

Analog->Television
Analog->Composite
Analog->S-Video

(Note: this is for the HD3000. Maybe the HD5500 is different.)

14. Select Analog->Television

15. Click "Scan for channels"

It should start scanning and finding channels.

16. When its done, exit and go to channel editor.

17. Change the name of the new channels from "Adding new channel"
(or whatever it is) to something like "Analog 7" or "KABC NTSC",
whatever you like.

18. Exit mythtv-setup and start mythfrontend

19. Go into 'Settings'

20. Go into 'TV settings'

21. Go into 'Recording profiles'

22. Go into 'Software encoders (v4l based)'

23. Go into 'Default'

24. Change the audio rate to 48000

25. Exit and also do the same in Live TV, High quality and Low quality

26. Exit all the way out and 'Watch TV'

Enjoy the new channels, and notice how crappy analog is
compared to digital. ;)

For the record, I still see massive stuttering on
analog channels. I suspect that its because the system
can't keep up with the bitrate. (My CPU is only a little
over 50%.)

I'm hoping that when I record a show and transcode it
to MPEG2, that it will play nicely after that. If anyone
has a better suggestion, would love to hear it.

Also, if anyone knows that it will work with Schedules
Direct, it would be nice to know how to do it.


More information about the mythtv-users mailing list