I have ran a few more tests of my own, which I thought I would pass along: The primary machine that I have experienced this issue on is: VIA C7 Processor 1000MHz with 512MB of RAM FreeBSD 7.1 i386. Liquidsoap 0.9.2-2 using OSS input module aotuv 20090303 libvorbis (http://www.geocities.jp/aoyoume/aotuv/)
For AAC+, metadata updates are actually sent over HTTP to icecast, just like MP3. I believe that the AAC+ streams are skipping when this occurs as well, but I am more concerned about Vorbis, so I have run these tests using a single vorbis stream. I have found that regardless of the quality level (-2.0, -1.0, 0), the skips can occur during metadata changes. In some situations I have found that the stream continues to loop the same audio over and over again and does not get unstuck until liquidsoap is restarted, which is really bad. I was able to make the skips occur by rapidly copy and pasting "meta.insert title='metadata'" over and over again into the telnet session. When skips occurred they were quite noticeable. I noticed this in top: Under normal conditions: CPU: 35.2% user, 0.0% nice, 2.2% system, 3.7% interrupt, 58.8% idle During metadata updates: CPU: 98.9% user, 0.0% nice, 0.7% system, 0.4% interrupt, 0.0% idle (It took me awhile to be able to copy-paste this from top as the CPU quickly spiked up and then went right back down) Interestingly enough, I performed the same tests on an Intel(R) Pentium(R) 4 CPU 3.00GHz with 1GB of RAM, again running FreeBSD 7.1 i386. The skips also occurred on this machine but they were far less noticeable. The audio just had a little "blip" in it on metadata updates. So it appears that there is a quick spike in CPU usage that is happening on metadata updates, which is exemplified on slower hardware. I would really like to get liquidsoap working on this machine. Is there anything that can be done? I would be more than happy to run any more tests or help out in any other way. Thanks! Andrew On 2010-05-21, at 2:25 AM, David Baelde wrote: > This is a known but elusive bug for Ogg streams. For AAC+ I'd say that > it's no surprise: I believe the external encoder is restarted when new > metadata arises, which is obviously time consuming. For Ogg streams, > there's no good reason. I have recently made some experiments [1] to > observe precisely the lag incurred by new metadata in Ogg/Vorbis > encoded streams but failed to see it on my setup. > > I'd understand that you don't feel like reproducing my experiments to > see what kind of result you get; we developers should try some > variations to see if we observe anything funny. Can you confirm the > problem with a simple script involving a single file (or even a sine) > output to both a vorbis file and soundcard? If so, please also > indicate your version of libvorbis and libogg. > > Hopefully, we'll stumble on a clue... > -- > David > > [1] http://www.lix.polytechnique.fr/~dbaelde/drift/clocks.html ------------------------------------------------------------------------------ _______________________________________________ Savonet-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/savonet-users
