The latency of a connection to the PulseAudio server is determined by
the tlength parameter. This was hardcoded to 10ms, which is a bit too
tight on my machine, causing audio on host and guest to malfunction.
A setting of 15ms works fine here. To allow tweaking, I also made the
setting configurable via the new -audiodev config. This allows to squeeze out better timings in scenarios where the emulation allows it.
I also removed setting of the minreq parameter to (seemingly arbitrary) half the latency, since it showed worse audio quality during my tests. Allowing PulseAudio to request smaller chunks helped.
Signed-off-by: Martin Schrodt <martin@schrodt.org>
Message-id:
20190315084653.120020-3-martin@schrodt.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
ss.channels = as->nchannels;
ss.rate = as->freq;
- /*
- * qemu audio tick runs at 100 Hz (by default), so processing
- * data chunks worth 10 ms of sound should be a good fit.
- */
- ba.tlength = pa_usec_to_bytes (10 * 1000, &ss);
- ba.minreq = pa_usec_to_bytes (5 * 1000, &ss);
+ ba.tlength = pa_usec_to_bytes(ppdo->latency, &ss);
+ ba.minreq = -1;
ba.maxlength = -1;
ba.prebuf = -1;
pdo->has_buffer_length = true;
pdo->buffer_length = 46440;
}
+ if (!pdo->has_latency) {
+ pdo->has_latency = true;
+ pdo->latency = 15000;
+ }
return 1;
}
#
# @name: name of the sink/source to use
#
+# @latency: latency you want PulseAudio to achieve in microseconds
+# (default 15000)
+#
# Since: 4.0
##
{ 'struct': 'AudiodevPaPerDirectionOptions',
'base': 'AudiodevPerDirectionOptions',
'data': {
- '*name': 'str' } }
+ '*name': 'str',
+ '*latency': 'uint32' } }
##
# @AudiodevPaOptions: