[mythtv-users] "Woodchuck" sound on TV playback

[Michael T. Dean]

On 08/12/2008 11:42 AM, James Oltman wrote:
> On Sun, Aug 10, 2008 at 7:00 PM, James Oltman wrote:
>> I've been trying to watch recordings from my HDHR device, and during
>> playback/watching TV I get this woodchuck noise through the speakers.  These
>> are the logs on the frontend:
>>
>> 2008-08-10 18:51:51.710 AFD: Opened codec 0x8657340, id(AC3) type(Audio)
>> 2008-08-10 18:51:51.718 Opening audio device 'default'. ch 6(2) sr 48000
>> 2008-08-10 18:51:51.719 Opening ALSA audio device 'default'.
>> 2008-08-10 18:51:53.260 Opening audio device 'default'. ch 2(2) sr 48000
>> 2008-08-10 18:51:53.260 Opening ALSA audio device 'default'.
>> 2008-08-10 18:51:54.089 VideoOutputXv: XVideo Adaptor Name: 'NV17 Video
>> Texture'
>> 2008-08-10 18:51:54.427 OSD Theme Dimensions W: 640 H: 480
>> 2008-08-10 18:51:55.010 TV: Changing from None to WatchingPreRecorded
>> 2008-08-10 18:51:55.016 The realtime priority setting is not enabled.
>> 2008-08-10 18:51:55.116 Video timing method: USleep with busy wait
>> 2008-08-10 18:51:56.010 NVP: prebuffering pause
>>
>> I am outputting all audio out through my Creative Soundblaster Audigy
>> card's digital output.  It's working for ISO movies with Dolby Digital
>> Surround sound and Xvid and MP3s etc.  I'm running MythBuntu 8.04 on both
>> backend and frontend boxes.  I'm using ALSA:default for my sound output in
>> Myth.  Any ideas would be appreciated.  I'd love to watch the Opening
>> Ceremonies in HD.  Thanks!
> Should I be directing this question elsewhere?  I tried the ALSA IRC
> channel, and they directed me here.  Any help would be appreciated.  Thanks!

You mean chipmunk sound?  Like people talking with higher-pitched voices?

If so, and if you're using AC-3/DTS passthrough with Myth, the channel 
you're watching probably has 32kHz AC-3 which most (meaning nearly all) 
computer sound cards can't handle--they always slurp in AC-3 at 48kHz.

If you're not using passthrough, you simply need to configure the plug 
sample/rate/format conversion plugin for ALSA.  You can do so as 
directed at 
http://www.mythtv.org/wiki/index.php/Configuring_Digital_Sound#Setting_up_ALSA.27s_.asoundrc.2C_Properly  
.

Mike