[pulseaudio-discuss] crackle and stutter

[Brian J. Murrell]

It seems inevitable that my pulse audio server
(0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu21.1 on Ubuntu Maverick)
will start sounding crackly and stuttery when an application wants to
send "notification" type sounds.

When this happens, about the only useful thing I see in the "-vvv"
output is:

D: alsa-sink.c: Requested to rewind 22988 bytes.
D: alsa-sink.c: Limited to 22988 bytes.
D: alsa-sink.c: before: 5747
D: alsa-sink.c: after: 5747
D: alsa-sink.c: Rewound 22988 bytes.
D: sink.c: Processing rewind...
D: sink-input.c: Have to rewind 22988 bytes on render memblockq.
D: sink-input.c: Have to rewind 22988 bytes on render memblockq.
D: sink-input.c: Have to rewind 11496 bytes on implementor.
D: source.c: Processing rewind...
D: protocol-native.c: Requesting rewind due to rewrite.
D: alsa-sink.c: Requested to rewind 23120 bytes.
D: alsa-sink.c: Limited to 23120 bytes.
D: alsa-sink.c: before: 5780
D: alsa-sink.c: after: 5780
D: alsa-sink.c: Rewound 23120 bytes.
D: sink.c: Processing rewind...
D: sink-input.c: Have to rewind 23120 bytes on render memblockq.
D: sink-input.c: Have to rewind 23120 bytes on render memblockq.
D: sink-input.c: Have to rewind 11560 bytes on implementor.
D: source.c: Processing rewind...
D: protocol-native.c: Underrun on 'Playback Stream', 0 bytes in queue.
D: protocol-native.c: Requesting rewind due to rewrite.
D: alsa-sink.c: Requested to rewind 21480 bytes.
D: alsa-sink.c: Limited to 21480 bytes.
D: alsa-sink.c: before: 5370
D: alsa-sink.c: after: 5370
D: alsa-sink.c: Rewound 21480 bytes.
D: sink.c: Processing rewind...
D: sink-input.c: Have to rewind 21480 bytes on render memblockq.
D: sink-input.c: Have to rewind 21480 bytes on render memblockq.
D: sink-input.c: Have to rewind 10740 bytes on implementor.
D: source.c: Processing rewind...
D: protocol-native.c: Requesting rewind due to rewrite.
D: alsa-sink.c: Requested to rewind 21848 bytes.
D: alsa-sink.c: Limited to 21848 bytes.
D: alsa-sink.c: before: 5462
D: alsa-sink.c: after: 5462
D: alsa-sink.c: Rewound 21848 bytes.
D: sink.c: Processing rewind...
D: sink-input.c: Have to rewind 21848 bytes on render memblockq.
D: sink-input.c: Have to rewind 21848 bytes on render memblockq.
D: sink-input.c: Have to rewind 10924 bytes on implementor.
D: source.c: Processing rewind...
D: protocol-native.c: Underrun on 'Playback Stream', 0 bytes in queue.
D: protocol-native.c: Requesting rewind due to rewrite.
D: alsa-sink.c: Requested to rewind 20212 bytes.
D: alsa-sink.c: Limited to 20212 bytes.
D: alsa-sink.c: before: 5053
D: alsa-sink.c: after: 5053
D: alsa-sink.c: Rewound 20212 bytes.
D: sink.c: Processing rewind...
D: sink-input.c: Have to rewind 20212 bytes on render memblockq.
D: sink-input.c: Have to rewind 20212 bytes on render memblockq.
D: sink-input.c: Have to rewind 10108 bytes on implementor.
D: source.c: Processing rewind...
D: protocol-native.c: Requesting rewind due to rewrite.
D: alsa-sink.c: Requested to rewind 20336 bytes.
D: alsa-sink.c: Limited to 20336 bytes.
D: alsa-sink.c: before: 5084
D: alsa-sink.c: after: 5084
D: alsa-sink.c: Rewound 20336 bytes.
D: sink.c: Processing rewind...
D: sink-input.c: Have to rewind 20336 bytes on render memblockq.
D: sink-input.c: Have to rewind 20336 bytes on render memblockq.
D: sink-input.c: Have to rewind 10168 bytes on implementor.
D: source.c: Processing rewind...
D: protocol-native.c: Underrun on 'Playback Stream', 0 bytes in queue.
D: protocol-native.c: Requesting rewind due to rewrite.
D: alsa-sink.c: Requested to rewind 19012 bytes.
D: alsa-sink.c: Limited to 19012 bytes.
D: alsa-sink.c: before: 4753
D: alsa-sink.c: after: 4753
D: alsa-sink.c: Rewound 19012 bytes.
D: sink.c: Processing rewind...
D: sink-input.c: Have to rewind 19012 bytes on render memblockq.
D: sink-input.c: Have to rewind 19012 bytes on render memblockq.
D: sink-input.c: Have to rewind 9508 bytes on implementor.

I'm not really sure what this is telling me though.  Is the above
normal?  Is there something else I should be looking for?

During these periods of crackle and stutter, other "continuous" sound
output type applications, like audio/video apps seem to stutter as well
as if they are being blocked on their output by the pulse server and
it's attempting to handle these other "periodic" type applications that
send notification sounds and so on.

Thots?

b.

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