qemu/audio/wavaudio.c
Volker Rümelin 9833438ef6 audio: restore mixing-engine playback buffer size
Commit ff095e5231 "audio: api for mixeng code free backends"
introduced another FIFO for the audio subsystem with exactly the
same size as the mixing-engine FIFO. Most audio backends use
this generic FIFO. The generic FIFO used together with the
mixing-engine FIFO doubles the audio FIFO size, because that's
just two independent FIFOs connected together in series.

For audio playback this nearly doubles the playback latency.

This patch restores the effective mixing-engine playback buffer
size to a pre v4.2.0 size by only accepting the amount of
samples for the mixing-engine queue which the downstream queue
accepts.

Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
Reviewed-by: Akihiko Odaki <akihiko.odaki@gmail.com>
Message-Id: <20220301191311.26695-10-vr_qemu@t-online.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2022-03-04 11:05:13 +01:00

223 lines
6.3 KiB
C

/*
* QEMU WAV audio driver
*
* Copyright (c) 2004-2005 Vassili Karpov (malc)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qemu/host-utils.h"
#include "qemu/module.h"
#include "qemu/timer.h"
#include "qapi/opts-visitor.h"
#include "audio.h"
#define AUDIO_CAP "wav"
#include "audio_int.h"
typedef struct WAVVoiceOut {
HWVoiceOut hw;
FILE *f;
RateCtl rate;
int total_samples;
} WAVVoiceOut;
static size_t wav_write_out(HWVoiceOut *hw, void *buf, size_t len)
{
WAVVoiceOut *wav = (WAVVoiceOut *) hw;
int64_t bytes = audio_rate_get_bytes(&hw->info, &wav->rate, len);
assert(bytes % hw->info.bytes_per_frame == 0);
if (bytes && fwrite(buf, bytes, 1, wav->f) != 1) {
dolog("wav_write_out: fwrite of %" PRId64 " bytes failed\nReason: %s\n",
bytes, strerror(errno));
}
wav->total_samples += bytes / hw->info.bytes_per_frame;
return bytes;
}
/* VICE code: Store number as little endian. */
static void le_store (uint8_t *buf, uint32_t val, int len)
{
int i;
for (i = 0; i < len; i++) {
buf[i] = (uint8_t) (val & 0xff);
val >>= 8;
}
}
static int wav_init_out(HWVoiceOut *hw, struct audsettings *as,
void *drv_opaque)
{
WAVVoiceOut *wav = (WAVVoiceOut *) hw;
int bits16 = 0, stereo = 0;
uint8_t hdr[] = {
0x52, 0x49, 0x46, 0x46, 0x00, 0x00, 0x00, 0x00, 0x57, 0x41, 0x56,
0x45, 0x66, 0x6d, 0x74, 0x20, 0x10, 0x00, 0x00, 0x00, 0x01, 0x00,
0x02, 0x00, 0x44, 0xac, 0x00, 0x00, 0x10, 0xb1, 0x02, 0x00, 0x04,
0x00, 0x10, 0x00, 0x64, 0x61, 0x74, 0x61, 0x00, 0x00, 0x00, 0x00
};
Audiodev *dev = drv_opaque;
AudiodevWavOptions *wopts = &dev->u.wav;
struct audsettings wav_as = audiodev_to_audsettings(dev->u.wav.out);
const char *wav_path = wopts->has_path ? wopts->path : "qemu.wav";
stereo = wav_as.nchannels == 2;
switch (wav_as.fmt) {
case AUDIO_FORMAT_S8:
case AUDIO_FORMAT_U8:
bits16 = 0;
break;
case AUDIO_FORMAT_S16:
case AUDIO_FORMAT_U16:
bits16 = 1;
break;
case AUDIO_FORMAT_S32:
case AUDIO_FORMAT_U32:
dolog ("WAVE files can not handle 32bit formats\n");
return -1;
default:
abort();
}
hdr[34] = bits16 ? 0x10 : 0x08;
wav_as.endianness = 0;
audio_pcm_init_info (&hw->info, &wav_as);
hw->samples = 1024;
le_store (hdr + 22, hw->info.nchannels, 2);
le_store (hdr + 24, hw->info.freq, 4);
le_store (hdr + 28, hw->info.freq << (bits16 + stereo), 4);
le_store (hdr + 32, 1 << (bits16 + stereo), 2);
wav->f = fopen(wav_path, "wb");
if (!wav->f) {
dolog ("Failed to open wave file `%s'\nReason: %s\n",
wav_path, strerror(errno));
return -1;
}
if (fwrite (hdr, sizeof (hdr), 1, wav->f) != 1) {
dolog ("wav_init_out: failed to write header\nReason: %s\n",
strerror(errno));
return -1;
}
audio_rate_start(&wav->rate);
return 0;
}
static void wav_fini_out (HWVoiceOut *hw)
{
WAVVoiceOut *wav = (WAVVoiceOut *) hw;
uint8_t rlen[4];
uint8_t dlen[4];
uint32_t datalen = wav->total_samples * hw->info.bytes_per_frame;
uint32_t rifflen = datalen + 36;
if (!wav->f) {
return;
}
le_store (rlen, rifflen, 4);
le_store (dlen, datalen, 4);
if (fseek (wav->f, 4, SEEK_SET)) {
dolog ("wav_fini_out: fseek to rlen failed\nReason: %s\n",
strerror(errno));
goto doclose;
}
if (fwrite (rlen, 4, 1, wav->f) != 1) {
dolog ("wav_fini_out: failed to write rlen\nReason: %s\n",
strerror (errno));
goto doclose;
}
if (fseek (wav->f, 32, SEEK_CUR)) {
dolog ("wav_fini_out: fseek to dlen failed\nReason: %s\n",
strerror (errno));
goto doclose;
}
if (fwrite (dlen, 4, 1, wav->f) != 1) {
dolog ("wav_fini_out: failed to write dlen\nReaons: %s\n",
strerror (errno));
goto doclose;
}
doclose:
if (fclose (wav->f)) {
dolog ("wav_fini_out: fclose %p failed\nReason: %s\n",
wav->f, strerror (errno));
}
wav->f = NULL;
}
static void wav_enable_out(HWVoiceOut *hw, bool enable)
{
WAVVoiceOut *wav = (WAVVoiceOut *) hw;
if (enable) {
audio_rate_start(&wav->rate);
}
}
static void *wav_audio_init(Audiodev *dev)
{
assert(dev->driver == AUDIODEV_DRIVER_WAV);
return dev;
}
static void wav_audio_fini (void *opaque)
{
ldebug ("wav_fini");
}
static struct audio_pcm_ops wav_pcm_ops = {
.init_out = wav_init_out,
.fini_out = wav_fini_out,
.write = wav_write_out,
.buffer_get_free = audio_generic_buffer_get_free,
.run_buffer_out = audio_generic_run_buffer_out,
.enable_out = wav_enable_out,
};
static struct audio_driver wav_audio_driver = {
.name = "wav",
.descr = "WAV renderer http://wikipedia.org/wiki/WAV",
.init = wav_audio_init,
.fini = wav_audio_fini,
.pcm_ops = &wav_pcm_ops,
.can_be_default = 0,
.max_voices_out = 1,
.max_voices_in = 0,
.voice_size_out = sizeof (WAVVoiceOut),
.voice_size_in = 0
};
static void register_audio_wav(void)
{
audio_driver_register(&wav_audio_driver);
}
type_init(register_audio_wav);