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

[John P Poet]

On Tue, Aug 12, 2008 at 12:43 PM, Michael T. Dean
<mtdean at thirdcontact.com> wrote:
> 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

I also experience this if I am watch shows on some channels with
TIMESTRETCH enabled.  Everything will be fine, then a commercial will
be skipped, and I end up with chipmunk voices.  Only way to fix it, is
to stop playback, then restart it.  This does not happen if
TIMESTRETCH is not in use.

I filed a ticket on this:
http://svn.mythtv.org/trac/ticket/5126

John
-- 
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