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From: Brad Midgley <bmidgley@xmission.com>
To: bluez-devel@lists.sourceforge.net
Subject: Re: [Bluez-devel] Advanced Audio Distribution Profile (A2DP)
Date: Tue, 21 Jun 2005 13:51:49 -0600	[thread overview]
Message-ID: <42B86FD5.8020204@xmission.com> (raw)
In-Reply-To: <1119378538.26772.127.camel@pegasus>

Marcel

>>i was hoping to get the timing problem hammered by using setitimer. 
>>unfortunately, there still seems to be some dependency on the cpu speed 
>>which is surprising to me. there's a place in the code where the time 
>>period reported by libsbc is multiplied by 87/100. that 87 has to be 
>>tweaked for different cpus :(
> 
> this is because the encoding itself takes some time. For that we need to
> encode up to 6 SBC frames in advance.

the way a2play is now, we do preencode. right now it's set so the 
encoder will get ahead by 3 packets (typically 6 frames each?). sigalarm 
fires off regularly to initiate the transmission of one packet.

as far as integer stuff, should we be doing something like a short float

struct sfloat {
  int16 mantissa;
  uint8 exponent;
}

or a fixed point 32-bit value? any idea what part of the 32 bits would 
be best to have in front and behind the decimal?

i guess i should start by having libsbc keep track of ranges of the 
different floats so we can figure out where the precision needs to be.

brad


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  reply	other threads:[~2005-06-21 19:51 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-06-21 15:28 [Bluez-devel] Advanced Audio Distribution Profile (A2DP) Victor Shcherbatyuk
2005-06-21 17:29 ` Marcel Holtmann
2005-06-21 18:02   ` Brad Midgley
2005-06-21 18:28     ` Marcel Holtmann
2005-06-21 19:51       ` Brad Midgley [this message]
2005-06-21 21:03         ` Marcel Holtmann
2005-06-22  0:16           ` Brad Midgley
2005-06-22  0:26             ` Marcel Holtmann
2005-06-22  7:56               ` Brad Midgley
2005-06-22 18:50                 ` Brad Midgley
2005-06-22 20:23                 ` Henryk Plötz
2005-06-22 21:36                   ` Brad Midgley
2005-06-22  6:45           ` Peter Robinson
  -- strict thread matches above, loose matches on Subject: below --
2005-06-22 15:27 Victor Shcherbatyuk
2005-06-22 16:39 ` Brad Midgley
2005-06-15 17:19 Claudio Takahasi
2005-06-15 17:47 ` wim delvaux
2005-06-15 17:49 ` Brad Midgley
2005-06-15 17:51 ` Henryk Plötz
2005-06-16 12:50   ` Claudio Takahasi
2005-06-22  8:54     ` Peter Robinson

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