[mythtv] [mythtv-commits] Ticket #10396: Periodical, short audio artifacts in one the channels when upmixing to 5.1

Mark Spieth mark at digivation.com.au
Thu Mar 8 06:33:18 UTC 2012

On 08/03/12 13:41, MythTV wrote:
>   The bug could be on how the upmixer handles when its buffer is completely
>   full...
>   but certainly now how audiooutputbase calls it
>   Having said that, this conditions occurs several times a minute, and I've
>   never seen the problem before, and I haven't had any reports of the
>   problem before.
>   We did have a similar issue and it turned out to be an ALSA issue when
>   using a particular audio buffer size.
>   To make sure that it's not what is occurring here, can you start the
>   frontend with:
>   ALSABufferOverride=200 mythfrontend -v audio
>   by default we use a value of 500ms, but this has caused problem for some.
I did check that 16 secs could be 3072000/2/2/48000 (mpeg2 x 2ch x 48k)
which is the primary buffer. Which indicates that its still a main 
buffer wrap issue.
Not that I understand yet.
Could it be that the first more is overwritten in the buffer than is 
absorbed and that the 2nd read of the buffer is invalid or has crap?
I also cant remember if the buffer was frame constrained or byte 
constrained in length?
I need to take a close look at everything. weekend perhaps.

apologies for my previous stupidity.


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