From acc3b63e1bdf806de1a520522dd43e494461d3bb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Volker=20R=C3=BCmelin?= Date: Sat, 4 Jan 2020 10:11:21 +0100 Subject: [PATCH] paaudio: try to drain the recording stream MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There is no guarantee a single call to pa_stream_peek every timer_period microseconds can read a recording stream faster than the data gets produced at the source. Let qpa_read try to drain the recording stream. To reproduce the problem: Start qemu with -audiodev pa,id=audio0,in.mixing-engine=off On the host connect the qemu recording stream to the monitor of a hardware output device. While the problem can also be seen with a hardware input device, it's obvious with the monitor of a hardware output device. In the guest start audio recording with audacity and notice the slow recording data rate. Signed-off-by: Volker Rümelin Message-id: 20200104091122.13971-4-vr_qemu@t-online.de Signed-off-by: Gerd Hoffmann --- audio/paaudio.c | 41 +++++++++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 16 deletions(-) diff --git a/audio/paaudio.c b/audio/paaudio.c index 7db1dc15f0..b23274550e 100644 --- a/audio/paaudio.c +++ b/audio/paaudio.c @@ -156,34 +156,43 @@ static size_t qpa_read(HWVoiceIn *hw, void *data, size_t length) { PAVoiceIn *p = (PAVoiceIn *) hw; PAConnection *c = p->g->conn; - size_t l; - int r; + size_t total = 0; pa_threaded_mainloop_lock(c->mainloop); CHECK_DEAD_GOTO(c, p->stream, unlock_and_fail, "pa_threaded_mainloop_lock failed\n"); - if (!p->read_length) { - r = pa_stream_peek(p->stream, &p->read_data, &p->read_length); - CHECK_SUCCESS_GOTO(c, r == 0, unlock_and_fail, - "pa_stream_peek failed\n"); - } + while (total < length) { + size_t l; + int r; - l = MIN(p->read_length, length); - memcpy(data, p->read_data, l); + if (!p->read_length) { + r = pa_stream_peek(p->stream, &p->read_data, &p->read_length); + CHECK_SUCCESS_GOTO(c, r == 0, unlock_and_fail, + "pa_stream_peek failed\n"); + if (!p->read_length) { + /* buffer is empty */ + break; + } + } - p->read_data += l; - p->read_length -= l; + l = MIN(p->read_length, length - total); + memcpy((char *)data + total, p->read_data, l); - if (!p->read_length) { - r = pa_stream_drop(p->stream); - CHECK_SUCCESS_GOTO(c, r == 0, unlock_and_fail, - "pa_stream_drop failed\n"); + p->read_data += l; + p->read_length -= l; + total += l; + + if (!p->read_length) { + r = pa_stream_drop(p->stream); + CHECK_SUCCESS_GOTO(c, r == 0, unlock_and_fail, + "pa_stream_drop failed\n"); + } } pa_threaded_mainloop_unlock(c->mainloop); - return l; + return total; unlock_and_fail: pa_threaded_mainloop_unlock(c->mainloop);