PDA

View Full Version : ogg playback occcasionally stops



jsqrdgsf
2007-10-31, 13:47
I'm having trouble with Squeezeboxes playing .ogg files.

I had the problem a while back (a year ago) when I started using SlimServer with a couple of Squeezeboxes. Mostly I just lived with it, or using Amarok instead(!)

Now recently, I've my Linux OS from SUSE 10.0 to Kubuntu (Gutsy Gibbon) and with it, I've upgraded to SlimServer 6.5.4 direct from the debian.slimserver.com (?) repository, and consequently upgraded the firmware on my two Squeezeboxes.

Mostly, the playback is fine, and when it works, the quality is great, even when synchronized to two separate Squeezebox players. But... every now and then, the playback hangs/stops/goes wrong.
Sometimes it just hangs. Sometimes it goes completely quiet but after a while starts the next track. Sometimes it thinks a bit and reverts to the beginning of the track. Once last night it did that 3 times, then played the track without error.

The tracks all seem to work OK in an alternate player, like Amarok. The tracks were recorded with grip, with the only anomaly being I was using grip (a GNOME utility) on KDE, which shouldn't affect its ability to rip .ogg files. The problems occur whether or not my players are synchronized.

Are there any utilities I can use to verify the integrity of my .ogg files? Failing that, any suggestions on what to do to see if this problem can be fixed.

Mark Lanctot
2007-11-01, 12:46
It seems the main problem with ogg is the sheer number of encoders, not all of which are compatible.

See http://forums.slimdevices.com/showthread.php?t=29904

That's an old thread, but I'm not sure if there have been any changes to the ogg decoder since, which was apparently very difficult to implement:

http://forums.slimdevices.com/showthread.php?t=38785

mik63
2007-11-03, 06:54
http://forums.slimdevices.com/showthread.php?t=39402

dcote
2007-11-13, 05:05
dear fellow ogg-user,

i fear i may have to confirm that using *non-reference* (as in: not released by xiph.org) vorbis encoders can cause playback problems.

i generally use SJeng's OggEncGTune3b1 encoder, which i find to have superior sound quality at *high* bitrates.
unfortunately, that encoder has allowed the bitrate so soar to ~500-600 kbits peak on some of my tracks and to ~350 kbits average.
these tracks cause my SB3 to choke. (reproduceable)

my solution: re-code those tracks in FLAC (since at that bitrate flac is not really that much larger) and/or turn off the visualization screensavers. seriously, it seems my SB3 was just running out of CPU cycles! and vorbis is *very* CPU-intensive...

luckily, only about 5 of my 3000 tracks seem to be affected, so i dont worry too much. as you said: other tracks sound fantastic!

and after all - its my fault. (not using the reference encoder ;-)

CatBus
2007-11-13, 11:39
Strangely enough, I've never had this problem with Ogg playback and my whole collection is encoded with a non-Xiph encoder (aoTuV).

I think it actually has more to do with bitrate than whether an encoder is standard or not. Ogg bitrates can fluctuate quite a bit within a single track, and I imagine there's an upper limit to what the decoder can handle.

The best solution in the long run may be to do your own ABX testing, and determine the bitrate where Ogg reaches transparency for you. If you haven't done this, then you're likely to encode your music to a needlessly high bitrate, which will overtax your SB3 and waste disk space.

Until then, you can disable the built-in Ogg decoding and set SlimServer to transcode to FLAC.

dcote
2007-11-14, 01:25
hi catbus - it seems my favorite encoder GTune3b1 is the culprit. when i encoded the offending tracks with xiph's reference at q10, everything played just fine.

but i agree with you that ultimately the higher bitrates with gtune3b1 are causing the crashes.