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authorVolker Rümelin <vr_qemu@t-online.de>2022-09-23 20:36:34 +0200
committerGerd Hoffmann <kraxel@redhat.com>2022-10-11 10:17:08 +0200
commit90320051ea998b6ac336cd635f8014ccb31154bd (patch)
treeab428a0b08f5880766a0f612a0ea569c2ad5f07d
parent02732641c0ffdedb6533b9ddeaf8e95a3be88ec6 (diff)
spiceaudio: add a pcm_ops buffer_get_free function
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 <vr_qemu@t-online.de> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20220923183640.8314-6-vr_qemu@t-online.de> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
-rw-r--r--audio/spiceaudio.c12
1 files 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,