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>
Acked-by: Markus Armbruster <armbru@redhat.com>
Message-id:
9315afe5-5958-c0b4-ea1e-
14769511a9d5@t-online.de
Message-Id: <
20210110100239.27588-3-vr_qemu@t-online.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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, );
{
/* 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 */
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:
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;
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;
'*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:
#
# Options of the wav audio backend.
'jack': 'AudiodevJackOptions',
'oss': 'AudiodevOssOptions',
'pa': 'AudiodevPaOptions',
- 'sdl': 'AudiodevGenericOptions',
+ 'sdl': 'AudiodevSdlOptions',
'spice': 'AudiodevGenericOptions',
'wav': 'AudiodevWavOptions' } }
#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"
``-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