Audiophile alert: flac decoding on Squeezebox required

> -----Original Message-----
> From: discuss-bounces (AT) lists (DOT) slimdevices.com
> [mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of
> Phillip Kerman
> Sent: 24 August 2004 20:36
> To: 'Slim Devices Discussion'
> Subject: [slim] Audiophile alert: flac decoding on
> Squeezebox required
>
> I guess I don't understand how slimserver plays FLAC now. If
> I turn off the bit rate limiting, doesn't it play the FLAC at
> 100%? Is the issue that you want, on the board,
> decompression on the SB itself?

As I see it, there are two issues:

1. Server load
To playback flac files it is necessary to use flac to convert the .flac
files to a pcm stream on the fly, leading to ...

2. Network load
Streaming 44.1kbs audio uses a lot of bandwidth.

The solution would be to decode flac at the squeezebox thus eliminating both
problems.

R.
--
http://robinbowes.com

[Nalle Johansson]

Slim Devices Discussion <discuss (AT) lists (DOT) slimdevices.com> på
den 24 augusti 2004 vid 17:34 +0100 skrev:
>Oh, also. Are there any other devices using the wireless?
>They take
>their piece from the bandwidth pie as well.
And if a microwave is on it steals bandwidth to.
CelluarPhones, portable phones and other things can lower
your bandwith to - the don´t need to use this radio-area
but will disturb it anyway.


Bästa hälsningar/Best Regards
Nalle Johansson

[Darren White]

> > 2. Network load
> > Streaming 44.1kbs audio uses a lot of bandwidth.
> That's the part I don't really get. My FLACs come in at just under
> 1Mbits/s. But my 802.11b wireless network tops out at 11Mbits/s. Even if
> I'm way at the other end of my house I get 2 Mbits... but the FLACs still
> drop out.

11Mbit half duplex. TCP has the ack packets, so you have a
constant back and forth of packets to maintain the tcp stream. This
means that your 11MBit will generally perform at somewhere around
half of that speed. Thats assuming small packets on the return. If the
packets are evenly sized, expect less than half the throughput. Now,
account for dropped packets/retransmissions at the radio level, and
your 11Mbit link starts to look like 10Base2. (not quite that bad,
10Base2 can give 5Mbit 802.11b a run for its money) A 1Mbit stream
will probably just get by on a 2Mbit connection, assuming not too
many dropouts.

Oh, also. Are there any other devices using the wireless? They take
their piece from the bandwidth pie as well.

UDP is actually better in this case, because it eliminates the need to
transmit return packets, allowing the wireless to stream nearly full
speed in one direction.

Thats why I always prefer wired. 10BaseT Full duplex will kick the
crap out of 802.11b all 8 days of the week. That said, I stream
flac/wav wirelessly right now without trouble, full PCM, but I have a
good healthy wireless signal. :)

Darren White
InterStar Inc.
530-224-6866 x 103

[Daryle A. Tilroe]

robin-lists (AT) robinbowes (DOT) com wrote:

> As I see it, there are two issues:
>
> 1. Server load
> To playback flac files it is necessary to use flac to convert the .flac
> files to a pcm stream on the fly, leading to ...
>
> 2. Network load
> Streaming 44.1kbs audio uses a lot of bandwidth.
>
> The solution would be to decode flac at the squeezebox thus eliminating both
> problems.

Don't forget '3' which doubles the benefit of 2 in terms of
dropout prevention:

3. Approximately double the depth of the receive buffer
in relation to seconds of buffered music stored.

I guess there is also a '1a' because I suspect it would solve the
problem of orphan flac tasks on the server and slimserver/squeezebox
confusion over the state of an aborted playing flac file:
http://bugs.slimdevices.com/show_bug.cgi?id=419

--
Daryle A. Tilroe

[Larry Truesdale]

Would native FLAC support also allow us to scan forward and backwards
through songs?

Larry

On Tue, 24 Aug 2004 17:52:05 -0600, Daryle A. Tilroe
<daryle (AT) micralyne (DOT) com> wrote:
> robin-lists (AT) robinbowes (DOT) com wrote:
>
> > As I see it, there are two issues:
> >
> > 1. Server load
> > To playback flac files it is necessary to use flac to convert the .flac
> > files to a pcm stream on the fly, leading to ...
> >
> > 2. Network load
> > Streaming 44.1kbs audio uses a lot of bandwidth.
> >
> > The solution would be to decode flac at the squeezebox thus eliminating both
> > problems.
>
> Don't forget '3' which doubles the benefit of 2 in terms of
> dropout prevention:
>
> 3. Approximately double the depth of the receive buffer
> in relation to seconds of buffered music stored.
>
> I guess there is also a '1a' because I suspect it would solve the
> problem of orphan flac tasks on the server and slimserver/squeezebox
> confusion over the state of an aborted playing flac file:
> http://bugs.slimdevices.com/show_bug.cgi?id=419
>
> --
> Daryle A. Tilroe
>
>
>
>

[Daryle A. Tilroe]

Larry Truesdale wrote:

> Would native FLAC support also allow us to scan forward and backwards
> through songs?

Just thought of this possible '4' myself. Would be another
great advantage.

--
Daryle A. Tilroe