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MythTV works fine but no audio in MythVideo -- PVR-350
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Author:  psuwtb [ Wed Feb 28, 2007 8:18 pm ]
Post subject:  MythTV works fine but no audio in MythVideo -- PVR-350
Hi all--

I have been running a basic MythTV setup without any problems (i.e. simply recording and playback of TV) for the past three or four months. Now I am trying to get MythVideo to work on my KnoppMyth setup but am not receiving any audio. I currently have my audio fed directly from my PVR-350 to my TV (not looped to a sound card as is generally configured). With this said, I have the option checked (selected) under TV settings / playback for "TV audio through PVR-350 only." This seems to work flawlessly for recording TV programs and playing them back; but the audio for MythVideo does not work. I have tried all of the popular players thru the MythVideo configuration menu (e.g., xine, mplayer, Internal, etc.) and had the same result -- video plays fine but no audio.

After setting up a temporary loop from my PVR-350 to my internal soundcard and sending the output to a pair of headphones, I had no audio problems thru MythVideo. Rather than purchase several cables and configure MythTV in this way, is there any way that I can force MythVideo to work directly from the PVR-350 as I am doing for MythTV?

Thanks for any help that you can provide!

Bill :?:
Author:  grante [ Fri Mar 02, 2007 12:09 pm ]
Post subject:  Re: MythTV works fine but no audio in MythVideo -- PVR-350
psuwtb wrote:
Hi all--

I[...] I currently have my audio fed directly from my PVR-350 to my TV (not looped to a sound card as is generally configured). With this said, I have the option checked (selected) under TV settings / playback for "TV audio through PVR-350 only." This seems to work flawlessly for recording TV programs and playing them back; but the audio for MythVideo does not work. I have tried all of the popular players thru the MythVideo configuration menu (e.g., xine, mplayer, Internal, etc.) and had the same result -- video plays fine but no audio.

[...]
AFAIK, none of those players can send sound through the PVR-350. In order to do that, they'd have to encode the video/audio inside an mpeg transport stream and send them to the 350's MPEG decoder device.

That's not how the players work -- they output "raw" video to the 350's raw video device and "raw" audio to an audio device (the 350 is not an audio device).
Quote:
After setting up a temporary loop from my PVR-350 to my internal soundcard and sending the output to a pair of headphones, I had no audio problems thru MythVideo. Rather than purchase several cables and configure MythTV in this way, is there any way that I can force MythVideo to work directly from the PVR-350 as I am doing for MythTV?

No (somebody please correct me if I'm wrong). [If there was, why would people bother with looping the audio from the 350 through their sound cards?]
Author:  psuwtb [ Sat Mar 03, 2007 3:33 pm ]
Post subject: 
Grant--

Thanks for the response! I bought a new cable and now have my PVR-350 audio output to my sound card's input and then sent to the TV. This seems to work fine for MythVideo but I do not have sound for live TV or for any of my recorded programs. I deselected the option to use the PVR-350 for sound and I am still having this same problem. Is it possible to have the PVR-350 looped to the soundcard to work for both live TV and for MythVideo, or must I constantly switch cables to make it work? If it is possible, what settings do I need to change to make the audio work for live TV?

Thanks again for your help!

Bill
Author:  grante [ Mon Mar 05, 2007 11:07 am ]
Post subject: 
Quote:
I bought a new cable and now have my PVR-350 audio output to my sound card's input and then sent to the TV. This seems to work fine for MythVideo but I do not have sound for live TV or for any of my recorded programs.

You may have the volume for the sound card's "line" input set to 0 (muted).

Try ssh'ing into the box and checking the mixer settings with amixer or alsamixer. Make sure both "line" (the signal from the '350) and "pcm" (the signal from things like mplayer) are unmuted and set to 70-90%.
Author:  psuwtb [ Mon Mar 05, 2007 4:53 pm ]
Post subject: 
Grant--

Looks like that did the trick, thanks for all of your help!

Bill
Author:  myth@chakobsa.net [ Sat Jul 28, 2007 8:43 am ]
Post subject:  Mythtv works but no sound in MythVideo - PVR350 + Soundcard
I just did a fresh install of R5F1 on a new hard drive and then restored configurations and data from my old R5C7 (I think that was the version) installation that was running on the same hardware (except for the new disk).

I'm using PVR-350 video out and it's looped through a sound card.

I just did a bunch of the fixes I found by searching the forum and the Wiki, and I have now regained the ability to record and playback in Mythtv.

When I play back divx/xvid and DVD ISOs in MythVideo I get picture but no sound. I've tried using aumix and alsamixer to adjust all possible volume settings to max but there's still no sound with Videos.

Any ideas? This worked fine on the same hardware before. I think aumix works fine because there are no errors and it adjusts the volume of Mythtv playback up and down, but it has no effect on MythVideo playback.

Running mplayer from a shell window I get the following in the output:

Code:
Opening audio decoder: [liba52] AC3 decoding with liba52
Using SSE optimized IMDCT transform
Using MMX optimized resampler
AUDIO: 48000 Hz, 2 ch, s16le, 192.0 kbit/12.50% (ratio: 24000->192000)
Selected audio codec: [a52] afm: liba52 (AC3-liba52)
==========================================================================
alsa-lib: pcm_params.c:2152:(snd_pcm_hw_refine_slave) Slave PCM not usable
alsa-init: unable to get initial parameters: Invalid argument
Could not open/initialize audio device -> no sound.
Audio: no sound


but I haven't had much luck with this in Google. I tried "chmod 777 /dev/dsp" and "chmod 777 /dev/mixer" but that didn't help.
Author:  myth@chakobsa.net [ Tue Jul 31, 2007 3:11 pm ]
Post subject:  userid issue with mplayer sound
I've done some more research and determined that the userid makes a difference. Running mplayer as userid mythtv gives this (non-audio related output not included):

Code:
Opening audio decoder: [liba52] AC3 decoding with liba52
Using SSE optimized IMDCT transform
Using MMX optimized resampler
AUDIO: 48000 Hz, 2 ch, s16le, 192.0 kbit/12.50% (ratio: 24000->192000)
Selected audio codec: [a52] afm: liba52 (AC3-liba52)
==========================================================================
alsa-lib: pcm_params.c:2152:(snd_pcm_hw_refine_slave) Slave PCM not usable
alsa-init: unable to get initial parameters: Invalid argument
Could not open/initialize audio device -> no sound.
Audio: no sound
Starting playback...


But running as my own userid that I created during the install process I get the following results on the same file:

Code:
Opening audio decoder: [liba52] AC3 decoding with liba52
Using SSE optimized IMDCT transform
Using MMX optimized resampler
AUDIO: 48000 Hz, 2 ch, s16le, 192.0 kbit/12.50% (ratio: 24000->192000)
Selected audio codec: [a52] afm: liba52 (AC3-liba52)
==========================================================================
AO: [alsa] 48000Hz 2ch s16le (2 bytes per sample)
Starting playback...


What possible configuration could be user specific and affect audio playback? In mythtv's ~/.mplayer/config there is only one setting, "monitoraspect=1.5" which I tried removing just in case, but that didn't help.

In /etc/group, both my userid and the mythtv userid are in the audio group.

Any idea what other user specific settings I could check?
Author:  myth@chakobsa.net [ Wed Aug 08, 2007 7:43 pm ]
Post subject:  Aha!
I found it! Doing the restore restored all the files in /home/mythtv including .asoundrc

When I removed .asoundrc sound was restored. I guess this file was needed in R5C7 but is no longer needed in R5F1 and prevents mplayer from producing sound.
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