From 90320051ea998b6ac336cd635f8014ccb31154bd Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Volker=20R=C3=BCmelin?= Date: Fri, 23 Sep 2022 20:36:34 +0200 Subject: [PATCH] spiceaudio: add a pcm_ops buffer_get_free function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit It seems there is a demand [1] for low latency playback over SPICE. Add a pcm_ops buffer_get_free function to reduce the playback latency. The mixing engine buffer becomes a temporary buffer. [1] https://lists.nongnu.org/archive/html/qemu-devel/2022-01/msg01644.html Signed-off-by: Volker Rümelin Reviewed-by: Marc-André Lureau Message-Id: <20220923183640.8314-6-vr_qemu@t-online.de> Signed-off-by: Gerd Hoffmann --- audio/spiceaudio.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/audio/spiceaudio.c b/audio/spiceaudio.c index a8d370fe6f..22892a7b9d 100644 --- a/audio/spiceaudio.c +++ b/audio/spiceaudio.c @@ -120,6 +120,13 @@ static void line_out_fini (HWVoiceOut *hw) spice_server_remove_interface (&out->sin.base); } +static size_t line_out_get_free(HWVoiceOut *hw) +{ + SpiceVoiceOut *out = container_of(hw, SpiceVoiceOut, hw); + + return audio_rate_peek_bytes(&out->rate, &hw->info); +} + static void *line_out_get_buffer(HWVoiceOut *hw, size_t *size) { SpiceVoiceOut *out = container_of(hw, SpiceVoiceOut, hw); @@ -133,8 +140,6 @@ static void *line_out_get_buffer(HWVoiceOut *hw, size_t *size) *size = MIN((out->fsize - out->fpos) << 2, *size); } - *size = audio_rate_get_bytes(&hw->info, &out->rate, *size); - return out->frame + out->fpos; } @@ -142,6 +147,8 @@ static size_t line_out_put_buffer(HWVoiceOut *hw, void *buf, size_t size) { SpiceVoiceOut *out = container_of(hw, SpiceVoiceOut, hw); + audio_rate_add_bytes(&out->rate, size); + if (buf) { assert(buf == out->frame + out->fpos && out->fpos <= out->fsize); out->fpos += size >> 2; @@ -282,6 +289,7 @@ static struct audio_pcm_ops audio_callbacks = { .init_out = line_out_init, .fini_out = line_out_fini, .write = audio_generic_write, + .buffer_get_free = line_out_get_free, .get_buffer_out = line_out_get_buffer, .put_buffer_out = line_out_put_buffer, .enable_out = line_out_enable,