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View Full Version : Stuttering, and the File Types page



Brian Ritchie
2006-10-14, 17:37
Tonight I got the fright of my life, when my SB3 started stuttering during playback of FLAC files. It was horrifying! Once might have been a temporary glitch; but then it did it again, and again.

I've not really tracked down the problem yet. Turned on Network & Performance monitoring, which showed nothing different from usual. (Admittedly, "usual" includes a signal strength of 50-60%, even when my laptop in the same room says the signal strength is Excellent. Well, maybe that's Microsoft's definition of Excellent :-)).

Eventually, turning on the buffer fullness view showed that the buffer was pretty much empty. Yet all other indicators look fine: as I said, signal strength hasn't gone down, and the server stats think it's doing OK.

However, earlier in the day, I *did* muck around with the File Format Conversion Setup in Server Settings / File Types. By default, it seems that everything is checked here. I have no idea what it means, but assumed that FLAC would be handled natively by default. So today I decided to uncheck all but the native support for FLAC (and WMA, and most of the others). Maybe I'm wrong; maybe FLAC has been getting transcoded all along!

Could someone explain, or point me to an explanation of, the Conversion page in the SS browser? For example, if multiple options are selected for FLAC (i.e. Stream Format values FLAC, MP3 and WAV), what happens when I pick a FLAC file to play?

It's hard to believe that my wireless network can't deliver FLAC fast enough to keep the Squeezebox happy.

I'm hoping that my recent switch from 6.2.2 to 6.5.0 (and soon after, to a 6.5.1 nightly) isn't somehow responsible. Going back to 6.2.2 would be a last resort.

-- Brian

radish
2006-10-15, 08:24
The network test plugin will give you an idea of what your usable bandwidth is.

In terms of the conversion page, you are selecting which formats/conversions are available for use. Which one is actually used depends on the source file format and the type of player. Each player has a preference order for formats (for SB3 I think it's FLAC, WAV, WMA, OGG, MP3) - the server either sends the file as-is if that's possible, or otherwise finds the transcoding path which ends up with the highest preference file type. So streaming FLAC will always send FLAC if you have "FLAC/FLAC (built-in)" selected.

lordhong
2006-10-15, 11:22
I have exactly the same problem (see my other post)... signal strenght at 100% at 5000, yet my buffer is always empty :( and most of my files are stuttering (even mp3).

Is there any way to tinker with the buffer settings?

peterbell
2006-10-15, 11:38
Much the same here - Wireless signal strength runs at around 90%, network test shows 99+% at 4000, yet I get spells of stuttering. :(

I have been wondering whether it's due to the perfomance hit that 6.5.0 seems to have had on the QNAP. I must try using a wired connection for a while to see how that performs.

Triode
2006-10-15, 11:48
In the latter case this could be lack of server CPU resources. NetTest overreads if it runs out of server cpu power. [5000 is too high for a wireless connection to a real squeezebox!]

Enable the server performance monitoring (Server and Network Health section of Help on web front page) and leave on for a while while you are playing tracks. Then post the output of the response time graph.

Brian Ritchie
2006-10-15, 12:01
The network test plugin will give you an idea of what your usable bandwidth is.


It might, if only I could see it for long enough! When I run any of the Network tests, I get a very brief view of a page that includes an empty graph, and then the main test page reloads on top of it!

Perhaps I should try it in a different theme (I'm using Fishbone)... ah, no: it works OK in IE, but not in Firefox (damn!)

I've been running the 5000kbps test for several minutes now, and it's averaging 99.6%, with a minimum of 82%. Of course, I don't know what the figures would have been last night, when the stuttering was happening. (I've not been playing flac files today, by chance.)

Now I know how to run the tests, I'll be ready to do them next time stuttering starts.

Oh, and thanks for the explanation. Sounds like FLAC should be FLAC, etc.

-- Brian

Brian Ritchie
2006-10-15, 12:49
In the latter case this could be lack of server CPU resources. NetTest overreads if it runs out of server cpu power. [5000 is too high for a wireless connection to a real squeezebox!]

Enable the server performance monitoring (Server and Network Health section of Help on web front page) and leave on for a while while you are playing tracks. Then post the output of the response time graph.

... and your response appeared when I posted my last!

I've been playing FLAC files for about 20 minutes now, with server performance monitoring on. At the moment, the graph looks like this:

Server Response Time
The response time of the server - the time between successive calls to select.
< 0.002 : 82375 : 96% ###############################################
< 0.005 : 2467 : 3% #
< 0.01 : 255 : 0%
< 0.015 : 172 : 0%
< 0.025 : 395 : 0%
< 0.05 : 246 : 0%
< 0.1 : 278 : 0%
< 0.5 : 29 : 0%
< 1 : 4 : 0%
< 5 : 1 : 0%
>=5 : 0 : 0%
max : 1.138204
min : 0.000027
avg : 0.000847

(I forgot to reset the counters, so this probably includes figures from during the network test as well; but I don't think they've been monotonically decreasing since I started looking.)

No stuttering, even when I started doing other things on the PC (transcoding, downloading). However, just as I returned downstairs, my wife said that the SB display had gone blank! The current track was still playing. I hit Now Playing on the remote, and the SB said it couldn't connect. I've seen this before on power-on; I pressed left (which showed me the IP address of the PC), then right, and it connected OK. THe current track finished, and playback stopped instead of going on to the next track. When I hit play, it started playing the track that had just finished. Hit next, and all was well. *Then* I started this message, and pasted the current server stats. Odd!

-- Brian

Triode
2006-10-15, 12:59
That doesn't look too bad, though it would be good to see with the stats reset to 0 first.

If you get persitent readings over 0.5 seconds then this could cause stuttering. In this case its worth enabling logging of events which take over 0.5 seconds [go to bottom of page and put 0.5 in the High box nxt to "Set All" and press "Set All". Leave running for a while whilst playing and then look at the server log - does it show any warnings about response times?

Alternative, itts possible you have something that causes short bursts of wireless interference - so that nettest normally runs OK, but would drop for a second during the interference. To see this start nettest from the server web interface and look at the graph - do you see any readings below 90% if left to run for an hour or so?

Brian Ritchie
2006-10-15, 16:19
It's been playing flacs for a couple of hours now, and here's the response time graph (reset at the start):

< 0.002 : 78859 : 89% ############################################
< 0.005 : 6360 : 7% ###
< 0.01 : 272 : 0%
< 0.015 : 1254 : 1%
< 0.025 : 357 : 0%
< 0.05 : 216 : 0%
< 0.1 : 1249 : 1%
< 0.5 : 31 : 0%
< 1 : 3 : 0%
< 5 : 2 : 0%
>=5 : 0 : 0%
max : 2.712229
min : 0.000027
avg : 0.001738

This is probably more realistic.

There have been a few >0.5 responses; I think most of these happened when I replaced the current playlist with another album. No sign of stuttering or low buffer (except at track ends, of course); but I've not been listening for the last hour or so (shame!)

-- Brian