A mix of bug fixes and improvements. Patches 01/23 - 11/23 have a few SDL fixes and add audio recording functions to the SDL audio backend.
Patch 12/23 removes unnecessary code from audio/audio.c. Patches 13/23 - 16/23 fix a few PulseAudio backend bugs. Patch 17/23 shows a PulseAudio backend bug. So far I don't think I broke any fine tuned user settings and I don't want to do it here. Patches 18/23 - 19/23 are the first steps towards glitch free and lower latency PulseAudio playback and recording. Currently qemu uses incredibly large buffers in the PulseAudio backend. For playback this just increases the playback latency but doesn't improve dropout safety, because PulseAudio can't access this buffer directly. With these patches it's possible to move the large qemu buffer to the PulseAudio server side and just keep a small buffer on the qemu side. On the PulseAudio server side PulseAudio tries to place a part of these buffers directly on the hardware and PulseAudio runs with a higher priority than qemu, so it has a better chance to deliver audio data in time. Here is an example to show how this works: -device intel-hda -device hda-duplex,audiodev=audio0 -machine pcspk-audiodev=audio0 -audiodev pa,id=audio0, out.buffer-length=14000,out.latency=46440,in.latency=46440 Due to a bug in the PulseAudio backend, these command line options actually decrease the playback latency compared to current defaults. For playback with defaults (16 bits, stereo, 44100 samples/s) we have a 15ms server side buffer + 2 * 46.44ms qemu audio buffer + 23.22ms hda codec buffer = 131.1ms latency. With my example it's 46.44ms + 2 * 14ms + 23.22ms = 97.66ms latency and I guess you won't hear any drop outs. Btw.: 14ms = 10ms timer-period + 4ms additional playback data the hda codec can produce in timer-period time. Patches 20/23 - 23/23 fix small issues with DirectSound. Volker Rümelin (23): sdlaudio: remove leftover SDL1.2 code audio: fix bit-rotted code sdlaudio: add -audiodev sdl,out.buffer-count option sdlaudio: don't start playback in init routine sdlaudio: always clear the sample buffer sdlaudio: fill remaining sample buffer with silence sdlaudio: replace legacy functions with modern ones audio: split pcm_ops function get_buffer_in sdlaudio: add recording functions audio: break generic buffer dependency on mixing-engine sdlaudio: enable (in|out).mixing-engine=off audio: remove remaining unused plive code paaudio: avoid to clip samples multiple times paaudio: wait for PA_STREAM_READY in qpa_write() paaudio: wait until the playback stream is ready paaudio: remove unneeded code paaudio: comment bugs in functions qpa_init_* paaudio: limit minreq to 75% of audio timer_rate paaudio: send recorded data in smaller chunks dsoundaudio: replace GetForegroundWindow() dsoundaudio: rename dsound_open() dsoundaudio: enable f32 audio sample format dsoundaudio: fix log message audio/alsaaudio.c | 3 +- audio/audio.c | 48 +++---- audio/audio_int.h | 2 + audio/audio_legacy.c | 3 +- audio/audio_template.h | 2 +- audio/audio_win_int.c | 73 ++++++---- audio/dsound_template.h | 2 +- audio/dsoundaudio.c | 6 +- audio/jackaudio.c | 1 + audio/noaudio.c | 1 + audio/ossaudio.c | 1 + audio/paaudio.c | 71 ++++++++-- audio/sdlaudio.c | 305 ++++++++++++++++++++++++++++------------ audio/spiceaudio.c | 1 + qapi/audio.json | 33 ++++- qemu-options.hx | 8 +- 16 files changed, 399 insertions(+), 161 deletions(-) -- 2.26.2
