From 2c2ca1c949553b59c54431ec179b31a697004492 Mon Sep 17 00:00:00 2001 From: Arun Raghavan Date: Thu, 9 Mar 2017 09:58:23 +0530 Subject: [PATCH] echo-cancel: Try to minimise in-flight chunks in snapshot latency We don't always know whether the in-flight memory chunks will be rendered or skipped (if the source is not in RUNNING). This can cause us to have an erroneous estimate of drift, particularly when the canceller starts. To avoid this, we explicitly flush out the send and receive sides of the message queue of audio chunks going from the sink to the source before trying to perform a resync. --- src/modules/echo-cancel/module-echo-cancel.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/modules/echo-cancel/module-echo-cancel.c b/src/modules/echo-cancel/module-echo-cancel.c index 14a148a3d..4f80be407 100644 --- a/src/modules/echo-cancel/module-echo-cancel.c +++ b/src/modules/echo-cancel/module-echo-cancel.c @@ -689,8 +689,13 @@ static void do_resync(struct userdata *u) { pa_log("Doing resync"); /* update our snapshot */ - source_output_snapshot_within_thread(u, &latency_snapshot); + /* 1. Get sink input latency snapshot, might cause buffers to be sent to source thread */ pa_asyncmsgq_send(u->sink_input->sink->asyncmsgq, PA_MSGOBJECT(u->sink_input), SINK_INPUT_MESSAGE_LATENCY_SNAPSHOT, &latency_snapshot, 0, NULL); + /* 2. Pick up any in-flight buffers (and discard if needed) */ + while (pa_asyncmsgq_process_one(u->asyncmsgq)) + ; + /* 3. Now get the source output latency snapshot */ + source_output_snapshot_within_thread(u, &latency_snapshot); /* calculate drift between capture and playback */ diff_time = calc_diff(u, &latency_snapshot);