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From: "Volker Rümelin" <vr_qemu@t-online.de>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: "Markus Armbruster" <armbru@redhat.com>,
	QEMU <qemu-devel@nongnu.org>,
	"Zoltán Kővágó" <dirty.ice.hu@gmail.com>
Subject: [PATCH 03/23] sdlaudio: add -audiodev sdl,out.buffer-count option
Date: Sun, 10 Jan 2021 11:02:19 +0100
Message-ID: <20210110100239.27588-3-vr_qemu@t-online.de> (raw)
In-Reply-To: <9315afe5-5958-c0b4-ea1e-14769511a9d5@t-online.de>

Currently there is a crackling noise with SDL2 audio playback.
Commit bcf19777df: "audio/sdlaudio: Allow audio playback with
SDL2" already mentioned the crackling noise.

Add an out.buffer-count option to give users a chance to select
sane settings for glitch free audio playback. The idea was taken
from the coreaudio backend.

The in.buffer-count option will be used with one of the next
patches.

Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
---
 audio/audio.c          |  2 +-
 audio/audio_legacy.c   |  3 ++-
 audio/audio_template.h |  2 +-
 audio/sdlaudio.c       | 11 +++++++++--
 qapi/audio.json        | 33 ++++++++++++++++++++++++++++++++-
 qemu-options.hx        |  8 +++++++-
 6 files changed, 52 insertions(+), 7 deletions(-)

diff --git a/audio/audio.c b/audio/audio.c
index b48471bb3f..d048d26283 100644
--- a/audio/audio.c
+++ b/audio/audio.c
@@ -2003,7 +2003,7 @@ void audio_create_pdos(Audiodev *dev)
         CASE(JACK, jack, Jack);
         CASE(OSS, oss, Oss);
         CASE(PA, pa, Pa);
-        CASE(SDL, sdl, );
+        CASE(SDL, sdl, Sdl);
         CASE(SPICE, spice, );
         CASE(WAV, wav, );
 
diff --git a/audio/audio_legacy.c b/audio/audio_legacy.c
index ffdbd0bcce..0fe827b057 100644
--- a/audio/audio_legacy.c
+++ b/audio/audio_legacy.c
@@ -286,7 +286,8 @@ static void handle_sdl(Audiodev *dev)
 {
     /* SDL is output only */
     get_samples_to_usecs("QEMU_SDL_SAMPLES", &dev->u.sdl.out->buffer_length,
-                         &dev->u.sdl.out->has_buffer_length, dev->u.sdl.out);
+        &dev->u.sdl.out->has_buffer_length,
+        qapi_AudiodevSdlPerDirectionOptions_base(dev->u.sdl.out));
 }
 
 /* wav */
diff --git a/audio/audio_template.h b/audio/audio_template.h
index 8dd48ce14e..434df5d5e7 100644
--- a/audio/audio_template.h
+++ b/audio/audio_template.h
@@ -337,7 +337,7 @@ AudiodevPerDirectionOptions *glue(audio_get_pdo_, TYPE)(Audiodev *dev)
     case AUDIODEV_DRIVER_PA:
         return qapi_AudiodevPaPerDirectionOptions_base(dev->u.pa.TYPE);
     case AUDIODEV_DRIVER_SDL:
-        return dev->u.sdl.TYPE;
+        return qapi_AudiodevSdlPerDirectionOptions_base(dev->u.sdl.TYPE);
     case AUDIODEV_DRIVER_SPICE:
         return dev->u.spice.TYPE;
     case AUDIODEV_DRIVER_WAV:
diff --git a/audio/sdlaudio.c b/audio/sdlaudio.c
index 00cd12ba66..431bfcfddd 100644
--- a/audio/sdlaudio.c
+++ b/audio/sdlaudio.c
@@ -276,12 +276,18 @@ static int sdl_init_out(HWVoiceOut *hw, struct audsettings *as,
     int endianness;
     int err;
     AudioFormat effective_fmt;
+    AudiodevSdlPerDirectionOptions *spdo = s->dev->u.sdl.out;
     struct audsettings obt_as;
 
     req.freq = as->freq;
     req.format = aud_to_sdlfmt (as->fmt);
     req.channels = as->nchannels;
-    req.samples = audio_buffer_samples(s->dev->u.sdl.out, as, 11610);
+    /*
+     * This is wrong. SDL samples are QEMU frames. The buffer size will be
+     * the requested buffer size multiplied by the number of channels.
+     */
+    req.samples = audio_buffer_samples(
+        qapi_AudiodevSdlPerDirectionOptions_base(spdo), as, 11610);
     req.callback = sdl_callback;
     req.userdata = sdl;
 
@@ -301,7 +307,8 @@ static int sdl_init_out(HWVoiceOut *hw, struct audsettings *as,
     obt_as.endianness = endianness;
 
     audio_pcm_init_info (&hw->info, &obt_as);
-    hw->samples = obt.samples;
+    hw->samples = (spdo->has_buffer_count ? spdo->buffer_count : 4) *
+        obt.samples;
 
     s->initialized = 1;
     s->exit = 0;
diff --git a/qapi/audio.json b/qapi/audio.json
index 072ed79def..9cba0df8a4 100644
--- a/qapi/audio.json
+++ b/qapi/audio.json
@@ -301,6 +301,37 @@
     '*out':    'AudiodevPaPerDirectionOptions',
     '*server': 'str' } }
 
+##
+# @AudiodevSdlPerDirectionOptions:
+#
+# Options of the SDL audio backend that are used for both playback and
+# recording.
+#
+# @buffer-count: number of buffers (default 4)
+#
+# Since: 6.0
+##
+{ 'struct': 'AudiodevSdlPerDirectionOptions',
+  'base': 'AudiodevPerDirectionOptions',
+  'data': {
+    '*buffer-count': 'uint32' } }
+
+##
+# @AudiodevSdlOptions:
+#
+# Options of the SDL audio backend.
+#
+# @in: options of the recording stream
+#
+# @out: options of the playback stream
+#
+# Since: 6.0
+##
+{ 'struct': 'AudiodevSdlOptions',
+  'data': {
+    '*in':  'AudiodevSdlPerDirectionOptions',
+    '*out': 'AudiodevSdlPerDirectionOptions' } }
+
 ##
 # @AudiodevWavOptions:
 #
@@ -385,6 +416,6 @@
     'jack':      'AudiodevJackOptions',
     'oss':       'AudiodevOssOptions',
     'pa':        'AudiodevPaOptions',
-    'sdl':       'AudiodevGenericOptions',
+    'sdl':       'AudiodevSdlOptions',
     'spice':     'AudiodevGenericOptions',
     'wav':       'AudiodevWavOptions' } }
diff --git a/qemu-options.hx b/qemu-options.hx
index 1698a0c751..4e02e9bd76 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -588,6 +588,7 @@ DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev,
 #endif
 #ifdef CONFIG_AUDIO_SDL
     "-audiodev sdl,id=id[,prop[=value][,...]]\n"
+    "                in|out.buffer-count= number of buffers\n"
 #endif
 #ifdef CONFIG_SPICE
     "-audiodev spice,id=id[,prop[=value][,...]]\n"
@@ -745,7 +746,12 @@ SRST
 ``-audiodev sdl,id=id[,prop[=value][,...]]``
     Creates a backend using SDL. This backend is available on most
     systems, but you should use your platform's native backend if
-    possible. This backend has no backend specific properties.
+    possible.
+
+    SDL specific options are:
+
+    ``in|out.buffer-count=count``
+        Sets the count of the buffers.
 
 ``-audiodev spice,id=id[,prop[=value][,...]]``
     Creates a backend that sends audio through SPICE. This backend
-- 
2.26.2



  parent reply index

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-10 10:01 [PATCH 00/23] next round of audio patches Volker Rümelin
2021-01-10 10:02 ` [PATCH 01/23] sdlaudio: remove leftover SDL1.2 code Volker Rümelin
2021-01-14 15:28   ` Thomas Huth
2021-01-10 10:02 ` [PATCH 02/23] audio: fix bit-rotted code Volker Rümelin
2021-01-14 14:32   ` Gerd Hoffmann
2021-01-31 17:13     ` Volker Rümelin
2021-01-10 10:02 ` Volker Rümelin [this message]
2021-01-14 14:27   ` [PATCH 03/23] sdlaudio: add -audiodev sdl, out.buffer-count option Gerd Hoffmann
2021-01-31 17:30     ` Volker Rümelin
2021-01-15  8:39   ` Markus Armbruster
2021-01-10 10:02 ` [PATCH 04/23] sdlaudio: don't start playback in init routine Volker Rümelin
2021-01-15  6:28   ` Thomas Huth
2021-01-10 10:02 ` [PATCH 05/23] sdlaudio: always clear the sample buffer Volker Rümelin
2021-01-15  6:31   ` Thomas Huth
2021-01-10 10:02 ` [PATCH 06/23] sdlaudio: fill remaining sample buffer with silence Volker Rümelin
2021-01-14 16:58   ` Thomas Huth
2021-01-17  9:41     ` Volker Rümelin
2021-01-10 10:02 ` [PATCH 07/23] sdlaudio: replace legacy functions with modern ones Volker Rümelin
2021-01-15  7:04   ` Thomas Huth
2021-01-10 10:02 ` [PATCH 08/23] audio: split pcm_ops function get_buffer_in Volker Rümelin
2021-01-10 10:02 ` [PATCH 09/23] sdlaudio: add recording functions Volker Rümelin
2021-01-10 10:02 ` [PATCH 10/23] audio: break generic buffer dependency on mixing-engine Volker Rümelin
2021-01-10 10:02 ` [PATCH 11/23] sdlaudio: enable (in|out).mixing-engine=off Volker Rümelin
2021-01-10 10:02 ` [PATCH 12/23] audio: remove remaining unused plive code Volker Rümelin
2021-01-10 10:02 ` [PATCH 13/23] paaudio: avoid to clip samples multiple times Volker Rümelin
2021-01-10 10:02 ` [PATCH 14/23] paaudio: wait for PA_STREAM_READY in qpa_write() Volker Rümelin
2021-01-10 10:02 ` [PATCH 15/23] paaudio: wait until the playback stream is ready Volker Rümelin
2021-01-10 10:02 ` [PATCH 16/23] paaudio: remove unneeded code Volker Rümelin
2021-01-10 10:02 ` [PATCH 17/23] paaudio: comment bugs in functions qpa_init_* Volker Rümelin
2021-01-10 10:02 ` [PATCH 18/23] paaudio: limit minreq to 75% of audio timer_rate Volker Rümelin
2021-01-10 10:02 ` [PATCH 19/23] paaudio: send recorded data in smaller chunks Volker Rümelin
2021-01-10 10:02 ` [PATCH 20/23] dsoundaudio: replace GetForegroundWindow() Volker Rümelin
2021-01-10 10:02 ` [PATCH 21/23] dsoundaudio: rename dsound_open() Volker Rümelin
2021-01-10 10:02 ` [PATCH 22/23] dsoundaudio: enable f32 audio sample format Volker Rümelin
2021-01-10 10:02 ` [PATCH 23/23] dsoundaudio: fix log message Volker Rümelin
2021-01-10 10:24 ` [PATCH 00/23] next round of audio patches no-reply
2021-01-10 23:09   ` Volker Rümelin
2021-01-14 14:36 ` Gerd Hoffmann

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