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hualon
2005-12-13, 12:20
After giving myself a six-month breather from the SB waiting for the software to mature, I hooked up my SB1 last night and I'm having problems. I'm willing to accept that the problem is with my configuration but I need a little help with the diagnosis.

The problem: audio playback will pause/choke for 5-10 seconds every few minutes.

The setup:
File Server Computer: Windows 2000 PC, P3-500 with 512MB RAM and one 250GB EIDE hard drive, 10/100 card. The server is not running any hosting services, it's merely a Windows 2K server with an active shared directory.

SlimServer Computer: (version downloaded last night, but not a nightly) Mac Mini running OS 10.4 with all updates, 1.42GHz G4, 1GB RAM, 10/100 card. The Mac isn't used for anything other than e-mail, iTunes, etc. I'm not running bittorrent clients or anything nutty that would eat up the bandwidth.

Both servers are hooked to a Linksys router/WAP/switch combo (WAP 54G, I believe) with the latest firmware (factory). All the cables check out and are terminated T568-B (as though it matters).

I'm running SlimServer on the Mac Mini because I use iTunes on the Mac with my iPod. The iTunes .xml file is stored on the Mac Mini but the music files are on a network share on the file server.

I'm using the analog outputs of the SB1, not the digital. Library scanning doesn't take very long but I have approximately 500 CDs ripped in APPLE LOSSLESS. Streaming from Internet radio sources seems to be working just fine so I'm leaning towards a file transfer bottleneck somewhere. On the other hand, I can open iTunes on the Mac and stream music off the server just like it were on the local hard drive without a hint of hiccup.

Is the problem:

1. Buffering problems with large file sizes over the network
2. Bottleneck caused by the (presumably) slow file server
3. Bottleneck caused by the file transfer twixt server & Mac
4. Slimserver in general
5. SB1 in general
6. Network Topography
7. SlimServer being separated from music files on a different machine
8. Sunspots
9. Other

Thanks!

hualon
2005-12-13, 18:09
Update: I got home from work and now the problem is every 10 seconds or so and lasts for up to 40 seconds.

Ben Sandee
2005-12-13, 18:39
On 12/13/05, hualon <hualon.2009mn (AT) no-mx (DOT) forums.slimdevices.com> wrote:
>
>
> Update: I got home from work and now the problem is every 10 seconds or
> so and lasts for up to 40 seconds.
>

Is the SB1 connected via Wireless? The SB1 buffer isn't huge --
particularly when streaming lossless audio. You might be suffering from
wireless network issues. The fact that you can play internet radio (low
bitrate, low bandwidth) indicates that this might be the issue:

Find your convert.conf and look for this section:

## you can comment this out if you want to use LAME to transcode AAC/MOV
files to MP3.
mov aif * *
[mov123] $FILE$

Try commenting out the lines by prefixing them with "#". This will force
the server to transcode your lossless files to MP3 which is much less
bandwidth-intensive. Restart SlimServer after doing this. If this works
then you should check your wireless reception. It has to be VERY good
reception in order to stream lossless reliably over a 802.11b connection.

Ben

Michaelwagner
2005-12-14, 00:01
Is the SB1 connected via Wireless? The SB1 buffer isn't huge -- particularly when streaming lossless audio.

Something like 5-8 seconds with lossy MP3s for an SB1. Tough if you don't have perfect reception. And worse if running lossless.

The SB1 uses 802.11b, which is roughly 11Mb/s. So when it tries to fill the buffer, it's slow. And the buffer is 8MB.

The SB2/3 is a better box for this. It's 802.11g, roughly 5 times faster. The buffer is 5 times bigger (40MB).

Both of those factors make it more fault tolerant.

That being said, we don't know the problem is wireless health. Try an experiment. Wire it up to ethernet and see if the problem goes away. If not, that's not it.

Oh, data from:
http://wiki.slimdevices.com/index.cgi?HardwareComparison

hualon
2005-12-14, 05:11
The SB is connected via a wired connection.

I was looking at the server activity and I noticed that on the Mac Mini (the Slim Server), I'm not receiving a sustained stream of incoming data from the file server.

When I look at the graph on the file server, I can see that it's transmitting data out not at a sustained bitrate but in pulses. The graph for the transmission data line peaks at 200KB/s or so and then plummets to 0KB/s for a second or so and then peaks back up.

So if I stop the SB playing and I stream the exact same file from the server into iTunes on the Mac Mini, I get a sustained transfer speed from the server of 130KB/s - 145KB/s with no plummets below that.

So it seems that when SlimServer (on the Mac Mini) requests a file, there are periodic dropouts from the server's transmission line but when iTunes (on the Mac Mini) requests the same file, there's a consistent data stream with no dropouts.

So... is the problem the buffer in the SB1? That's very frustrating if that's the case since it's *supposed* to be capable of playing lossless files. I've had this problem since day 1 when I bought the SB1 new and nobody ever suggested that the SB could be the problem since there are so many other variables in the system.

Michaelwagner
2005-12-14, 06:30
I don't know anything about apple lossless, or about apples in general, but it sounds like a dispatching problem on the mac mini. I can't think of a good reason that the server would stop sending data for one second unless the mac wasn't dispatching it.

If you have a packet sniffer, you should see a steady stream of packets back from the SB1, saying, amongst other things, buffer fullness. Do you? Do they get through? Is there a firewall somewhere in here?

If you're running a recent version of slimserver, there is a network health page that may help.

hualon
2005-12-14, 07:05
I don't know anything about apple lossless, or about apples in general, but it sounds like a dispatching problem on the mac mini. I can't think of a good reason that the server would stop sending data for one second unless the mac wasn't dispatching it.

If you have a packet sniffer, you should see a steady stream of packets back from the SB1, saying, amongst other things, buffer fullness. Do you? Do they get through? Is there a firewall somewhere in here?

If you're running a recent version of slimserver, there is a network health page that may help.

I'm not sure if there's a problem with the Mac or not. When I first had this SB hooked up, I was using *only* the P3-500 server and I was getting hiccups all the time too.

There's no firewall inside the network but there is one at the router going out to the Internet, that's not an issue.

How do I determine "buffer fullness" by using a packet sniffer on the SB1?

I am running the latest SlimServer from the site downloaded on Friday night. I don't want to move SlimServer over to the file server because then I'll lose my iTunes integration.

So if the SB1 is converting the lossless files down to MP3 and, therefore, completely destroying the POINT of having lossless files, could I just lower the stream size down in SlimServer?

-J

danco
2005-12-14, 08:21
On 14/12/05 at 06:05 -0800, hualon wrote
>So if the SB1 is converting the lossless files down to MP3 and,
>therefore, completely destroying the POINT of having lossless files,
>could I just lower the stream size down in SlimServer?

Well, it doesn't *completely* destroy the point of having lossless
files, as once you have them they are there for any wanted future use.

You don't say what variety of lossless files you have. If you have
aiff files, the wired SB will play them without transcoding. If you
have Apple lossless files, they will have to be transcoded, and it
may be that the issue is there.
--
Daniel Cohen

Michaelwagner
2005-12-14, 17:30
sorry, I wasn't very clear. The packet sniffer won't tell you by itself buffer fullness. One of the packets tells you that, but unless you can decipher the packets, it's not obvious (they're stored in certain packets, in binary, etc).

Better is to turn on the server health thing and let it analyze the packets and tell you.

Or turn on the buffer fullness display on the SB1.

hualon
2005-12-15, 05:09
On 14/12/05 at 06:05 -0800, hualon wrote[color=blue]

You don't say what variety of lossless files you have. If you have
aiff files, the wired SB will play them without transcoding. If you
have Apple lossless files, they will have to be transcoded, and it
may be that the issue is there.


I did, actually. They're all Apple lossless. Does that transcoding take place on the SlimServer or in the SB?

How do I turn on the buffer fullness display?

Can someone from Slim comment on this? I fail to understand why there can be a fundamental problem with playback of an officially supported file (Apple Lossless) that is *not* the fault of the host software or network topology. It seems to me then that the fault lies entirely in the hardware of the SB1 meaning that it does not, in fact, WORK as advertised.

newton
2005-12-15, 05:43
I just got a used SB1 awhile ago and was thinking of using my Mac Mini to run the SlimServer, but started out running it on a Windows machine. The SB1 is connected by wire to the server through a switch.

I haven't had any problems with the SB1. Have you tried serving some files residing on the Mac Mini instead of the file server? That would at least eliminate a problem from Mac Mini to SB1. My guess is that part works correctly (though I get the impression that the Mac version of SlimServer is not as solid as the Windows version for some reason).

I suspect that the problem is how the data is being requested from the file server, but I don't know enough about SlimServer yet to know how it opens the files, and whether it is something in SlimServer or lower in the Mac (OS X) plumbing. I'm sure someone around here knows the SlimServer part.

hualon
2005-12-15, 08:06
I just got a used SB1 awhile ago and was thinking of using my Mac Mini to run the SlimServer, but started out running it on a Windows machine. The SB1 is connected by wire to the server through a switch.

I haven't had any problems with the SB1. Have you tried serving some files residing on the Mac Mini instead of the file server? That would at least eliminate a problem from Mac Mini to SB1. My guess is that part works correctly (though I get the impression that the Mac version of SlimServer is not as solid as the Windows version for some reason).

I suspect that the problem is how the data is being requested from the file server, but I don't know enough about SlimServer yet to know how it opens the files, and whether it is something in SlimServer or lower in the Mac (OS X) plumbing. I'm sure someone around here knows the SlimServer part.

I'm pretty sure that it has to do with the file size that I'm streaming; I'm streaming Apple Lossless files (about 10MB / minute of audio).

I ran the Network Health thing this morning and the buffer fullness was consistently reporting as "Low".

Here's the setup:
http://danforthsource.com/pics/sb_net.bmp

When I examine the Mac Mini's network activity, the data RX during playback will hover around 140KB/s or so and then drops down to 5KB/s for no apparent reason (somewhere in step 3).

Again, when I stream a file from the server into iTunes on the Mac Mini directly, I have NO problems at all with the input stream.

So, I do have a network-related PUSH problem getting data into the SB1 buffer, right? The SB1 is *not* the problem? The processor on the Mac Mini is never pegged out so I don't think that I'm having any trouble with processing overhead in transcoding the files for rebroadcast.

Can someone from Slim please comment?

MrC
2005-12-15, 09:20
How do I turn on the buffer fullness display?

Under Player Settings in the web interface, there's a pulldown:

"Include buffer fullness in Playing Display Mode list".

Enable it there, and then use the Now Playing button on the remote to switch through the now playing interfaces until you find the buffer fullness display.

kdf
2005-12-15, 11:05
With an SB1, apple lossless is transcoded to WAV/AIFF. The sb1 also
has a small buffer (less than 1s) so any network delays can cause
hiccups, especially if used over wireless. Some users have no problem
(I was one of those), others had trouble getting it to work. It was
probably part of the motive behind the much larger buffer in the SB2
and the use of FLAC. There was a hope that SB1 would get flac support,
but the investigation into it showed that the CPU in the SB1 wasn't up
to the task. Hence, SB2/3 uses a much more powerful cpu.

One help for SB1 wireless is to use bitrate limiting, set at 320.
Unfortunately, this means mp3.

-kdf

hualon
2005-12-15, 11:59
With an SB1, apple lossless is transcoded to WAV/AIFF. The sb1 also
has a small buffer (less than 1s) so any network delays can cause
hiccups, especially if used over wireless. Some users have no problem
(I was one of those), others had trouble getting it to work. It was
probably part of the motive behind the much larger buffer in the SB2
and the use of FLAC. There was a hope that SB1 would get flac support,
but the investigation into it showed that the CPU in the SB1 wasn't up
to the task. Hence, SB2/3 uses a much more powerful cpu.

One help for SB1 wireless is to use bitrate limiting, set at 320.
Unfortunately, this means mp3.

-kdf

Very helpful, thank you!

So if I were to just bite the bullet and buy a SB2, would I get:

A) Higher resistance to audio dropouts
B) Higher audio quality when streaming Apple Lossless?

So does the transcoding process on the SB1 maintain the lossless audio quality or does it downsample? What about the SB2? I'm not concerned with the transcoded file format but I would prefer that it maintains its lossless quality.

Thanks!

kdf
2005-12-15, 12:16
Quoting hualon <hualon.203i2b (AT) no-mx (DOT) forums.slimdevices.com>:

> So if I were to just bite the bullet and buy a SB2, would I get:
>
> A) Higher resistance to audio dropouts

yes. The buffer is 64Mb now, plus the preferred trancoding format is
FLAC, using half the bandwidth of WAV without any loss is quality.

> B) Higher audio quality when streaming Apple Lossless?

That depends on how you use it. If you have SB1 on a wired network
transcoding to WAV and using the digital outs, it is probably the same.
The analog output is greatly improved with SB2/3, however.

> So does the transcoding process on the SB1 maintain the lossless audio
> quality or does it downsample? What about the SB2? I'm not concerned
> with the transcoded file format but I would prefer that it maintains
> its lossless quality.

SB1 when wired will transcode to WAV format, and by default for
wireless will transcode to MP3. The MP3 default is 320kbps, which is
fairly good quality but is still lossy. WAV would be lossless as long
as the source is lossless.

SB2 handles FLAC natively. FLAC is also a lossless format, so you will
have no loss in quality from your Apple Lossless files. Your CPU will
have to put in a bit more effort due to the on-the-fly conversion of
ALC-to-FLAC.

-kdf

gorstk
2005-12-15, 12:18
> A) Higher resistance to audio dropouts
> B) Higher audio quality when streaming Apple Lossless?
>
> So does the transcoding process on the SB1 maintain the lossless audio
> quality or does it downsample? What about the SB2? I'm not concerned
> with the transcoded file format but I would prefer that it maintains
> its lossless quality.

SB1 - the server will transcode to wav or mp3 depending on what you tell it.

SB2 - the server will transcode to either wav or flac (both lossless)

hualon
2005-12-15, 12:38
>
SB1 - the server will transcode to wav or mp3 depending on what you tell it.

SB2 - the server will transcode to either wav or flac (both lossless)

And how do you tell it which to transcode to? I'd like to transcode to MP3 on the SB1, to see if I can improve the skipping problem at the expense of degrading sound quality.

kdf
2005-12-15, 12:56
Quoting hualon <hualon.203jon (AT) no-mx (DOT) forums.slimdevices.com>:


> And how do you tell it which to transcode to? I'd like to transcode to
> MP3 on the SB1, to see if I can improve the skipping problem at the
> expense of degrading sound quality.
>
Each player type has a list of supported formats in preferred order.

SliMP3: mp3
SB1: AIFF WAV MP3
SB2: WMA FLAC AIFF WAV MP3
Softsqueeze: FLAC AIFF WAV MP3

Server settings->file types controls the set of enabled conversions,
including built in ones. There are none for transcoding to wma, so
that gets skipped for all but native conditions. If you disable any
others, they end up skipped as well until a valid match is found by
following the priority above.

In player settings->audio, there is a setting for bitrate limiting.
This forces a maximum bitrate to be used by the stream. This setting
forces mp3 output to any player using this setting. "No Limit" allows
normal streaming, while anything else is the MP3 bitrate. Try lowering
the bitrate until you get unbroken playback. If you still have
problems, check your CPU usage in case LAME is causing the cpu to be
overworked.

Both file types and bitrate limiting will show you if you have the
needed codecs installed. in File types, any conversions that have
missing binaries will show up as disabled. If you try to enable them,
you will get an error about a missing binary. In Bitrate limiting, the
description will report on whether or not the server has found a
version of LAME that it can use. If it is not found, then it has a
link at the end. You will need lame installed in order to get MP3
output. If lame does not exist, then bitrate limiting will not work
and the server will fallback to using WAV. This might be what is
happening in your case, since a wireless connection should already
default to 320kbps mp3 and play fine.

-kdf

tgoldstone
2005-12-15, 14:11
Very helpful, thank you!

So if I were to just bite the bullet and buy a SB2, would I get:

A) Higher resistance to audio dropouts
B) Higher audio quality when streaming Apple Lossless?



I ran into a similar problem. As neighbors piled on the wireless products my SB1 started dropping out with ever increasing frequency. I bought a SB2 for my main system and moved the SB1 into the bedroom as my alarm clock. Streaming wireless 320kbps mp3 works flawlessly. A win-win situation. Even the wife likes waking up to it (obviously the most important thing) :)

hualon
2005-12-16, 06:31
OK, I installed LAME and I'm now transcoding to MP3. I still have the network dropouts BUT I don't have any audio dropouts anymore.

I just bought a SB2 on eBay and I'm selling off the SB1, hopefully that will improve things.