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Subject: Re: Buffer Underrun
From: gerald clark (gerald_clark_at_mindspring.com)
Date: 2003-01-14


The situation with VBR at 16KHz is even worse.
The highest I can get the water mark with 7 sec
of anti-skip is C7F3.
the buffer count decrements by 10000.
10000 is above C7F3, so it doesn't even
check until the buffer is empty, so
I get a buffer under-run on every read.

gerald clark wrote:
> In view of your explanation, I have re-tested.
>
> I wait for the drive to spin down before playing the MP3.
> This assures a spin-up to get a proper water mark.
>
> The watermark value is the same, no matter
> what anti-skip is set to.
> It always appears as A410.
> I stop playing, and wait for the drive to spin down.
> I play the file again, and the watermark includes
> anti-skip time.
>
> The water mark value does not include anti-skip
> time until the 2nd spinup.
> At this point, the buffer has underrun.
>
> Linus Nielsen Feltzing wrote:
>
>> gerald clark wrote:
>>
>>> It does not appear to be calculating the watermark on the first play.
>>
>>
>>
>> The watermark calculation is based on the hard drive spinup time,
>> which is measured when the drive spins up. Tus, no watermark
>> calculation can be done until that time is measured, that is when the
>> drive spins up again after being idle.
>> Until then, the default value of 0x60000 is used.
>>
>>> It does not appear to read the Anti skip value unless you change it.
>>
>>
>>
>> The watermark calculation includes the anti-skip time, and will not be
>> used until the next spin-up.
>>
>> /Linus
>>
>>
>
>

-- 
Gerald L. Clark

Aero TerraTrike #1 http://www.wizwheelz.com/images/clarkaerotrike1.jpg

Member: Sky Soaring

Illinois, U.S.A.

Archos Recorder JBR20101 1.28 0x302 positive 0x200 positive 11.0592



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