[mythtv-users] Question regarding PVR-150

Ian Forde ian at duckland.org
Sun Sep 2 03:17:18 UTC 2007


On Sat, 2007-09-01 at 12:53 -0400, Michael T. Dean wrote:
> The archives were wrong, then.  (But, thank you for doing the research
> before posting. :)

No worries - been on the list a long time... I know how it works! ;)

> The proper way to change recording parameters is to go into the
> recording profile settings to change the audio sample rate there.  I
> recommend you do so now (to ensure the profile is properly configured).

There's the problem... In the recording profile settings, when I select
"MPEG-2 Encoders (PVR-250, PVR-350)" [1], select, let's say, "High
Quality", I can't change the Sampling rate.  It seems locked at 48000
(although I'm sure it was locked at 32000 before... and I just put those
db entries back into codecparams as they were before and restarted both
backends!)


> For future benefit, regardless of what you find in the archives, direct
> DB editing is almost never the right approach (generally, only when
> helping a dev do some test before a better approach is implemented or
> when doing "unsupported" things--in which case, calling it the "right"
> approach is arguable).  I for one would never "yell" at someone for not
> doing their research if they were to post a question like, "I found
> <whatever> in the archives saying to edit the DB directly.  Is there a
> better solution?"

Fair enough...

> You'll also need to configure your ALSA appropriately to do rate
> conversion for you.  See
> http://www.mythtv.org/wiki/index.php/Configuring_Digital_Sound#Setting_up_ALSA.27s_.asoundrc.2C_Properly

Did that over a year ago AFAIK...
the frontend is set to "Audio output device: ALSA:digital"
Passthrough output device: ALSA:iec958:{ AES0 0x02 }
Enable AC3 to SPDIF passthrough is checked
Aggressive Sound card Buffering is checked
Use Internal volume controls is unchecked

I'm using the same ~mythfrontend/.asoundrc and /etc/asound.state as I
had before...
 here's the .asoundrc file (comments stripped):

pcm.!default {
  type plug
  slave.pcm "digital-hw"
}

ctl.!default {
  type hw
  card 0
}

pcm.analog {
  type plug
  slave.pcm "analog-hw"
}

ctl.analog {
  type hw
  card 0
}

pcm.mixed-analog {
  type plug
  slave.pcm "dmix-analog"
}

ctl.mixed-analog {
  type hw
  card 0
}

pcm.digital {
  type plug
  slave.pcm "digital-hw"
}

ctl.digital {
  type hw
  card 0
}

pcm.mixed-digital {
  type plug
  slave.pcm "dmix-digital"
}

ctl.mixed-digital {
  type hw
  card 0
}


pcm.analog-hw {
  type hw
  card 0
  # The default value for device is 0, so no need to specify
}

ctl.analog-hw {
  type hw
  card 0
}

pcm.digital-hw {
  type hw
  card 0
  device 2
}

ctl.digital-hw {
  type hw
  card 0
}

pcm.dmix-analog {
  type dmix
  ipc_key 1234
  slave {
    pcm "analog-hw"
    period_time 0
    period_size 1024
    buffer_size 4096
    rate 48000
  } 
}

ctl.dmix-analog {
  type hw
  card 0
}

pcm.dmix-digital {
  type dmix
  ipc_key 1235
  slave {
    pcm "digital-hw"
    period_time 0
    period_size 1024
    buffer_size 4096
    rate 48000
  } 
}

ctl.dmix-digital {
  type hw
  card 0
}

But why was I getting the errors on capture?  I can see how ALSA would
be used to correct them during playback, but...

Okay - so the DB settings are as they were, so now I just need to reboot
the servers...

I'll post the results.  Thanks!

	-I

[1] - That could be changed to read: "MPEG-2 Encoders (PVR-*50)" - I
should send in a patch!



More information about the mythtv-users mailing list