[mythtvnz] audio pauses latm-aac

[Paul Kendall]

On Wed, Apr 4, 2012 at 9:29 PM, Brett <mythicalbeast at slingshot.co.nz> wrote:
> On Wed, 2012-04-04 at 07:39 +1200, Paul Kendall wrote:
>> On Tue, Apr 3, 2012 at 5:45 PM, Brett <mythicalbeast at slingshot.co.nz> wrote:
>> > Anybody else getting occasional audio pauses/silence (1/2 to 3 sec long
>> > at a rate of 2-5 times an hour) with recording from Prime dvb-t over the
>> > last 2-3 weeks?
>> >
>>
>> Now that you mention it, I did notice this in 'Mayday' that I watched
>> and was recorded on Prime.
>> I'll check my next recording from Prime and see if it happens again.
>>
>> > Both 0.24+fixes & 0.25 (2 weeks old) show this problem.
>> >
>> > Transcoding latm to AAC (libfacc) with latest ffmpeg plays fine , so
>> > does ancient VLC 1.0.6.
>> >
>>
>> If it transcodes correctly then it may be that our ALSA buffer is set
>> slightly too small.
>> Perhaps prime has moved from stereo to 5.1 sound and now the buffers
>> are sometimes
>> a little too small.
>>
>> I'll check tonight and again when Mayday records on Sunday night.
>>
>> Cheers,
>> Paul
>>
>
> I tried
> echo 512 | sudo tee /proc/asound/card0/pcm1p/sub0/prealloc
> and other much larger numbers; made no difference.
> Is this the same buffer you refer ?

Yes, that's the one I was talking about.

>
> mediainfo reports typical Prime as:
> 04/04/2012 as 2 ch HE-AAC/LC max 99Kbps
> 05/01/2012 much the same...
>

I have a recording from last night and was going to check this over easter.
I want to check to see that when it occurs if it is repeatable at the
same position
or if it is semi-random when it occurs.

What are your audio settings i.e. are you upmixing to 5.1 from this
stereo channel.
What is the upmixer set to, best, etc, (not at my machine so I cant
remember them off hand).
It may be that we can adjust these to work around the problem.

Like I said, I'll play around over easter and let you know.

> Thanks,
> Brett

Cheers,
Paul