[mythtv-users] Audio buffer underruns

[Victor Brunini]

On Sat, Aug 23, 2014 at 3:08 AM, Jean-Yves Avenard <jyavenard at gmail.com>
wrote:

> Hi
>
> Le samedi 23 août 2014, Victor Brunini <victorbrunini at gmail.com> a écrit :
>
> Hi all,
>>
>> I have a combined backend/frontend system that I've been using without
>> any issues for ~1 year now. Starting in the middle of this week I am
>> suddenly getting constant audio buffer underruns when trying to play any
>> video in mythtv. Thus far I have tried/tested:
>>
>> 1) Set /proc/asound/card0/pcm1p/sub0/prealloc to it's maximum value of
>> 32768.
>> 2) Tried both AC3 passthrough and standard PCM output in mythtv without
>> success. With PCM the audio is constantly stuttering. With AC3 passthrough
>> I get a brief (~1s) period of sound and after that see the receiver
>> constantly switching in and out of Dolby Digital mode due to the buffer
>> underruns.
>> 3) Confirmed that mplayer and VLC both play the same video files with
>> either PCM or AC3 passthrough without any issues.
>> 4) Confirmed that if I set the mythtv audio output device to NULL video
>> playback is very smooth and CPU usage is minimal (I'm using VDPAU for video
>> decoding).
>> 5) Tried updating to the latest v0.27.3-152-g926bb8d fixes version
>> available on the mythbuntu repositories (prior to the issues I had disabled
>> automatic updates).
>>
>> A section of the log file generated running with -v audio is available at
>> http://pastebin.com/J5wZgTYN
>>
>
> Problem is that you've cut your log too much... As a rule of thumb, when
> reporting a playback problem: never strip your code! As I'm guessing if you
> knew what to look for in the log, you wouldn't be asking on how to solve
> your problem here...
>
> What's your video card and what playback profile are you using?
> Change to VDPAU Normal
>
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Hi,

Here's the full pastebin for the log from starting mythfrontend to closing
mythfrontend: http://pastebin.com/bVqmLcpG

Video card is a GeForce 8400 GS, and I am using VDPAU Normal. I have also
tried VDPAU Slim and Slim. Those two appear to make it very slightly
farther (~2 seconds instead of ~1) into the recording before the buffer
underruns happen.

Thanks,
Victor
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