[winswitch] speaker-restart during video play in xpra 0.15

Jiang Qian jiang.qian at gmail.com
Fri Jun 5 02:52:58 BST 2015

Hi all,

After making some minor adjustments to my configuration (clipboard and
dpi, chiefly) I am settling happily to xpra 0.15 (both server and
client, both on Ubuntu 14.04) They are connected over unencrypted raw
tcp stream.

I am puzzled by one behavior. I am forwarding sound, using the
encoding Wavpak. (--speaker-code=wavepak) When I play an extended
video clips, I got a large number of (about 2-3 in row, sometimes)
re-starting speaker because of overrun.

So far, aside from the fact that the audio is slight out of sync from
the video, there seems to be no adverse consequences.

I do confess I am puzzled because I thought because xpra 0.15 seperate
audio to a separate process, the forwarding would be less prone to
network jitters and the like.

In addition, I am running over a high quality gigabit network, through
which thousands of ping roundtrips return without a single lost packet
and a nearly uniform roundtrip time of 0.25ms, so what *are* the
network congestions or jitters that affect the sound stream? The video
is far from saturating the bandwith, at merely 30-40MB/s when a
straight file transfer can approach 80-90MB/s.

If there is more debugging I could do, I will be happy to provide more

Thanks in advance.

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