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egd
2007-08-25, 15:37
Just wondering whether anyone knows how much bandwidth is consumed when streaming lossless FLAC audio to an SB3. Bascially I'm curious as to the point at which one would saturate an 85mbps netplug's throughput capability (all else being equal).

Mark Lanctot
2007-08-25, 16:08
The FLAC itself will be ~1000 kbps, although recent FLAC versions can make files with as little as 700 kbps. Add 250-500 kbps overhead, so you have ~1.5 Mbps per stream maximum.

If you actually have 85 Mbps through HomePlugs, you could run 56 simultaneous FLAC streams...I'm not sure about HomePlugs' actual bandwidth but I'm betting you won't get anywhere near 85 Mbps - however it's unlikely you have 56 Squeezeboxes either. ;-)

pfarrell
2007-08-25, 16:13
egd wrote:
> Just wondering whether anyone knows how much bandwidth is consumed when
> streaming lossless FLAC audio to an SB3. Bascially I'm curious as to
> the point at which one would saturate an 85mbps netplug's throughput
> capability (all else being equal).

You can get a decent estimate pretty easily.

On http://www.pfarrell.com/prc/bits.html I show how many bits are in a
RedBook stream, which is the raw, uncompressed PCM stream (wav, etc.)

The short answer is that raw PCM takes
= 1,411,200 bits/second
= 176,400 bytes/second
= 172 Kbytes/second

Most FLAC files are about half that, so they would require about
90Kbytes/second

To be safe, you should add in 20% or so for TCP/IP overhead, headers,
checksums, addresses, etc.

Thus one megabit per second, delivered is more than enough.

Pat

--
Pat
http://www.pfarrell.com/music/slimserver/slimsoftware.html

agentsmith
2007-08-26, 06:21
My experience with Homeplug, even my Panasonic Homeplug "AV", is that it does not go much over 4-5 Mega Bits per second. At least in my home electrical system they don't.

I have both Draft-N 2.0 and Homeplug AV installed at home, and neoither deliver close to what the adverts promised. But the Draft N environment is at least 3-4 times quicker than the Homeplug AV.

Just my experience, YMMV

Robin Bowes
2007-08-26, 07:31
agentsmith wrote:
> My experience with Homeplug, even my Panasonic Homeplug "AV", is that it
> does not go much over 4-5 Mega Bits per second. At least in my home
> electrical system they don't.

Are you sure you're not confusing mega *bits* with mega *bytes* ?

Homeplug is 85 mega *bits* / second, i.e. 10.625 mega *bytes* / second.

You won't get anywhere near that speed, but 4-5 mega *bytes* / second
would a reasonable speed from an 85 mega *bit* / second network.

R.

egd
2007-08-27, 02:14
thanks for the replies - I've just moved home and started getting intermittent dropouts on a SB3. At my previous place I was running two SB3s and a Transporter simultaneously via netplugs with no issues.

I swapped the unit that was losing the connection with another and the same thing happened, so I'm guessing its a wiring thing rather than a problem with my Squeezeboxes. Seems intermittent though, which is puzzling, and losing the network connection only seems to occur when streaming to two or more devices at the same time, so perhaps a netplug is faulty?

Mark Lanctot
2007-08-27, 07:30
Apparently HomePlugs' performance varies greatly from home to home, and apparently they don't work as well in North America as in Europe due to different wiring practices (which explains why they're more expensive and more difficult to find here).

teddy278
2007-08-28, 08:29
Hi egd,

I use devolo dlan 200av as a "backbone" for some parts of my network. They ship with a software telling me how fast each adapter is running at the moment. Maybe there is some software like that for your homeplugs as well, so that you can see if they connect all right?


Greetings!
teddy

egd
2007-08-28, 14:13
They ship with a software telling me how fast each adapter is running at the moment. Maybe there is some software like that for your homeplugs as well, so that you can see if they connect all right?

Teddy, thanks for reminding me about the software, I'd completely forgotten about it because the netplugs have just worked from day one. The only thing I'd used the software for previously was to set a network name.