From 4c3356f96557e848f0323772f9502d60817682dc Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Volker=20R=C3=BCmelin?= Date: Sun, 20 Sep 2020 19:17:22 +0200 Subject: [PATCH] audio/audio: fix video playback slowdown with spiceaudio MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch allows the audio backends get_buffer_out() functions to drop audio data and mitigates a bug reported on the qemu-devel mailing list. https://lists.nongnu.org/archive/html/qemu-devel/2020-09/msg03832.html The new rules for the variables buf and size returned by get_buffer_out() are: size == 0: Downstream playback buffer is full. Retry later. size > 0, buf != NULL: Copy size bytes to buf for playback. size > 0, buf == NULL: Drop size bytes. The audio playback rate with spiceaudio for the no audio case is too fast, but that's what we had before commit fb35c2cec5 "audio/dsound: fix invalid parameters error". The complete fix comes with the next patch. Reported-by: Qi Zhou Signed-off-by: Volker Rümelin Message-id: 20200920171729.15861-2-vr_qemu@t-online.de Signed-off-by: Gerd Hoffmann --- audio/audio.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/audio/audio.c b/audio/audio.c index 1a68cfaafb..7b660dd0c4 100644 --- a/audio/audio.c +++ b/audio/audio.c @@ -1091,12 +1091,15 @@ static size_t audio_pcm_hw_run_out(HWVoiceOut *hw, size_t live) while (live) { size_t size, decr, proc; void *buf = hw->pcm_ops->get_buffer_out(hw, &size); - if (!buf || size == 0) { + + if (size == 0) { break; } decr = MIN(size / hw->info.bytes_per_frame, live); - audio_pcm_hw_clip_out(hw, buf, decr); + if (buf) { + audio_pcm_hw_clip_out(hw, buf, decr); + } proc = hw->pcm_ops->put_buffer_out(hw, buf, decr * hw->info.bytes_per_frame) / hw->info.bytes_per_frame;