Please describe the problem:
In some initial tests, seeking seems to break on Ogg Vorbis files. This problem
may be related to the adder - the problem only exhibits itself when more than
one ogg file is played using the adder.

Attached is a test script that demonstrates the problem. On line 94, setting the
long value to 60 * gst.SECOND causes playback to fail with multiple ogg files.
Now, interestingly, I can get the ogg files to play if I do the following:

 1. First try to the play the two ogg files with the value on line 94 set to 60.
 It should fail.
 2. Comment out the ogg lines and uncomment the mp3 lines. Restart the program
and playback should work.
 3. Now comment out the mp3 files and uncomment the ogg files, and the ogg files
work!!

I have also discovered that the ogg files seem to play OK with other values on
line 94, such as '30 * gst.SECOND'. I don't get any seek/playback problems with
single ogg/mp3 files.

Steps to reproduce:
1. See above.
2. 
3. 


Actual results:
Playback fails.

Expected results:
Playback succeed.

Does this happen every time?
Mostly.

Other information: