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

Michael T. Dean mtdean at thirdcontact.com
Sat Aug 16 19:17:04 UTC 2008

On 08/16/2008 02:39 PM, Allen Edwards wrote:
> I also double checked my settings and I am red faced as they differ
> from what I remembered:
> Audio output device: ALSA:spdif
> Passthrougth output device: ALSA:iec958:(AESO 0x02)
> Max Audio Channels Stereo
> Upmis: Passive
> x Enable AC3 to SPDIF passthrough
> x Enable DTS to SPDIF passthrough
>   Aggressive Sound Card Buggers
Those buggers are not a good thing.
>   Use Internal volume controls
> (last 2 not checked)

You're almost definitely mixing up "Aggressive Sound card Buffering" 
with "Extra audio buffering" (since you didn't actually check the last 
2).  "Aggressive Sound card Buffering" is almost universally bad, while 
"Extra audio buffering"--basically the exact opposite functionality of 
"Aggressive Sound card Buffering"--is almost universally good.

In spite of the help text given with "Extra audio buffering", most 
everyone today needs "Extra audio buffering" enabled--not just PVR-x50 
users, but also anyone using digital TV broadcast as MPEG-2.  And, since 
the setting has no negative effects, there's no reason to disable it 
(it's enabled by default).


The settings:

Aggressive Sound card Buffering
If enabled, MythTV will pretend to have a smaller sound card buffer than 
is really present.  This may speed up seeking, but can also cause 
playback problems.

Extra audio buffering
Enable this setting if MythTV is playing "crackly" audio and you are 
using hardware encoding. This setting will have no effect on MPEG-4 or 
RTJPEG video. MythTV will keep extra audio data in its internal buffers 
to workaround this bug.

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