View Full Version : Streaming radio ok, streaming from server not ok

2006-10-02, 12:09
Hi there.
I am very frustrated with my set up. Granted I have the server (and internet modem/wifi router) on my 3rd floor and m SB on my first, I get an quite reliable connection (although medium to poor in % of full signal) which seems to be enough to play radio streams.
The same doesnt apply to music from my db.

Streams stop and drop and start again for a second and stall etc. Before I go down to the shop and buy a $130 "LAN over power line" plug and connect wired, I want to know if wifi reach is really my problem or it is something else.

Does it sound to you like it could be something else? Can one fiddle with buffer sizes, server versions, framware versions or anything else that might fix the problem.
I am on 6.3 now, but unless somebody swears that ony a server update will do the trick, I wont upgrade.
PS: my db size souldnt be the problem yet, I have only ripped 120 CD so far.

Mark Lanctot
2006-10-02, 12:29
What kind of files do you play? Specifically, what bitrate?

You can limit the bitrate by going to Player Settings - Audio - Bitrate Limiting.

Almost surely this is due to poor wireless reception and higher bitrate files, but if you wish you can go to Server & Network Health and enable performance monitoring, then post the output here. I can't remember where this was in 6.3 (Server Settings - Plugins? In Help?) but in 6.5 it's in Help.

6.5 won't be able to cure wireless issues but since the scanner process is separate, your music won't skip due to low server resources when you're scanning.

2006-10-04, 04:37
I play FLACs -whatever the bitrate is for them (ripped with EAC in safe mode).
I will try bringing my SB 1 feet away from the router and see if the problem persists... if it doesnt, then I think we found out that it is indeed the poor signal

2006-10-04, 07:08
FLAC uses typically 6-10 times the bandwidth of a normal radio stream, so I'm sure this is the problem. You have two choices - lower the bandwidth requirements using the bitrate limiting feature (this will lower sound quality) or improve the connection, using a booster, better antennas, some kind of wired connection, powerline, etc.

2006-10-05, 13:07
I did all kinds of trouble shooting hoping to find out that something else but the reach of my wireless is tha problem, but it seems that you are right.

Now, I still feel stupid, because I don't understand this:
If the signal dropped all the bleeding time, causing interruptions, I would understand why the communication buffers, skips, stales, play and then skips again.
But: in my case I just happen to have a low, constant,never dropping signal and the result is the same... Why?
Can I get a quasi-techno explanation on this?

So I can understand why drops to 0% signal will produce hicups. I can even understand why craming lots of datacom into a limited bandwith would produce hicup.

What I can not understand, intuitively, is why a weak signal produces hicups...

Please bear with my stupidity, and if you feel in a generous mood, please give it a shot at enlightning me.

Mark Lanctot
2006-10-05, 13:23
Bandwidth decreases with dropping signal strength, and dropping signal strength occurs over distance.

So you just don't have enough bandwidth due to the distance.

The Squeezebox is trying to do what it can. When you play a song, there's an initial burst of data in an attempt to fill the buffer. What happens in your case is that the player plays faster than the low bandwidth can refill the buffer, so the buffer empties.

You will find that due to random chance, sometimes it will be better than others. Not all FLACs are 1000 kbps, and environmental factors like humidity and interference from other devices play a part.

2006-10-05, 13:24
In a wireless network there's a relationship between the strength/cleanliness of the signal and the amount of data you can get through it. Think of two people shouting at each other over a distance. The further away they are, the quieter the sound and the harder it is to make out what the other person's saying. You have to keep repeating things and so the speed at which you can actually communicate useful information drops.

Now to playback audio we need a completely constant stream of data at a given rate (which depends on the format used - as discussed FLAC requires a much higher rate than MP3). Because little breaks and errors are present in ALL network types (including wired and wireless) the SB contains a buffer. When you start playing it first fills the buffer, and then plays from that - so any little glitches are ironed out.

If you need an analogy for a buffer, think of a store checkout clerk. They handle customers at a fixed rate regardless of how busy the store is. A buffer is like the queue in a busy store. Even if new customers join the queue at uneven intervals (say 5 join at once, then a few minutes later another couple join) the clerk will still serve people at the same constant rate as long as people are waiting - the queue irons out the inconsistency in supply. In this analogy the slimserver is providing the customers (data packets) into the queue (the buffer) for processing by the clerks (player).

This explains how the buffer works to cope with short, unexpected drops in the rate of arrival of data. But your case is different. In your case the _average_ rate of arrival in the buffer is less than the rate at which data is being taken out. So the store is quiet and very few customers are joining the queue. In this case there will be times when the queue is empty and the clerk has no-one left to serve - and that's when you hear a dropout.

Hope that made some sense :) To summarise - your data rate is constant but lower than the data rate of the file, and so the buffer frequently drains causing the dropouts.

2006-10-05, 13:30
Depending on your wifi, you may be able to put a booster wireless point (or even just a powrful antenna) to improve things.

That worked for me, though my situation isn't as extreme as yours.

2006-10-05, 14:34
Thank you all for your explanations. It's all clear to me now.

Now I will just have to decide whether I am giving up on wireless and get one of those LAN over powerline adaptors,
or get a new router with a better reach, or moving the darn stereo closer to my modem :)

or, of course, repeaters, antenae etc