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aaudio: Use the callback interface. 

This is allegedly lower-latency than the AAudioStream_write interface,
but more importantly, it let me set this up to block in WaitDevice.

Also turned on the low-latency performance mode, which trades battery life
for a more efficient audio thread to some unspecified degree.
main
Ryan C. Gordon 2023-07-29 19:44:23 -04:00
parent b49ce86765
commit 32a3fc3783
No known key found for this signature in database
GPG Key ID: FA148B892AB48044
2 changed files with 73 additions and 51 deletions
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106
src/audio/aaudio/SDL_aaudio.c
View File

@ -37,10 +37,8 @@
struct SDL_PrivateAudioData
{
AAudioStream *stream;
Uint8 *mixbuf; // Raw mixing buffer
int frame_size;
SDL_Semaphore *semaphore;
int resume; // Resume device if it was paused automatically
};
@ -75,8 +73,13 @@ static int AAUDIO_LoadFunctions(AAUDIO_Data *data)
static void AAUDIO_errorCallback(AAudioStream *stream, void *userData, aaudio_result_t error)
{
LOGI("SDL AAUDIO_errorCallback: %d - %s", error, ctx.AAudio_convertResultToText(error));
// !!! FIXME: you MUST NOT close the audio stream from this callback, so we cannot call SDL_AudioDeviceDisconnected here.
// !!! FIXME: but we should flag the device and kill it in WaitDevice/PlayDevice.
}
static aaudio_data_callback_result_t AAUDIO_dataCallback(AAudioStream *stream, void *userData, void *audioData, int32_t numFrames);
#define LIB_AAUDIO_SO "libaaudio.so"
static int AAUDIO_OpenDevice(SDL_AudioDevice *device)
@ -132,21 +135,39 @@ static int AAUDIO_OpenDevice(SDL_AudioDevice *device)
}
ctx.AAudioStreamBuilder_setFormat(builder, format);
ctx.AAudioStreamBuilder_setErrorCallback(builder, AAUDIO_errorCallback, hidden);
ctx.AAudioStreamBuilder_setErrorCallback(builder, AAUDIO_errorCallback, device);
ctx.AAudioStreamBuilder_setDataCallback(builder, AAUDIO_dataCallback, device);
ctx.AAudioStreamBuilder_setPerformanceMode(builder, AAUDIO_PERFORMANCE_MODE_LOW_LATENCY);
LOGI("AAudio Try to open %u hz %u bit chan %u %s samples %u",
device->spec.freq, SDL_AUDIO_BITSIZE(device->spec.format),
device->spec.channels, (device->spec.format & 0x1000) ? "BE" : "LE", device->sample_frames);
device->spec.channels, SDL_AUDIO_ISBIGENDIAN(device->spec.format) ? "BE" : "LE", device->sample_frames);
res = ctx.AAudioStreamBuilder_openStream(builder, &hidden->stream);
ctx.AAudioStreamBuilder_delete(builder);
if (res != AAUDIO_OK) {
LOGI("SDL Failed AAudioStreamBuilder_openStream %d", res);
ctx.AAudioStreamBuilder_delete(builder);
return SDL_SetError("%s : %s", __func__, ctx.AAudio_convertResultToText(res));
}
device->sample_frames = (int) ctx.AAudioStream_getFramesPerDataCallback(hidden->stream);
if (device->sample_frames == AAUDIO_UNSPECIFIED) {
// if this happens, figure out a reasonable sample frame count, tear down this stream and force it in a new stream.
device->sample_frames = (int) (ctx.AAudioStream_getBufferCapacityInFrames(hidden->stream) / 4);
LOGI("AAUDIO: Got a stream with unspecified sample frames per data callback! Retrying with %d frames...", device->sample_frames);
ctx.AAudioStream_close(hidden->stream);
ctx.AAudioStreamBuilder_setFramesPerDataCallback(builder, device->sample_frames);
res = ctx.AAudioStreamBuilder_openStream(builder, &hidden->stream);
if (res != AAUDIO_OK) { // oh well, we tried.
LOGI("SDL Failed AAudioStreamBuilder_openStream %d", res);
ctx.AAudioStreamBuilder_delete(builder);
return SDL_SetError("%s : %s", __func__, ctx.AAudio_convertResultToText(res));
}
}
ctx.AAudioStreamBuilder_delete(builder);
device->spec.freq = ctx.AAudioStream_getSampleRate(hidden->stream);
device->spec.channels = ctx.AAudioStream_getChannelCount(hidden->stream);
@ -161,9 +182,7 @@ static int AAUDIO_OpenDevice(SDL_AudioDevice *device)
return SDL_SetError("Got unexpected audio format %d from AAudioStream_getFormat", (int) format);
}
device->sample_frames = ctx.AAudioStream_getBufferCapacityInFrames(hidden->stream) / 2;
LOGI("AAudio Try to open %u hz %u bit chan %u %s samples %u",
LOGI("AAudio Actually opened %u hz %u bit chan %u %s samples %u",
device->spec.freq, SDL_AUDIO_BITSIZE(device->spec.format),
device->spec.channels, SDL_AUDIO_ISBIGENDIAN(device->spec.format) ? "BE" : "LE", device->sample_frames);
@ -178,7 +197,11 @@ static int AAUDIO_OpenDevice(SDL_AudioDevice *device)
SDL_memset(hidden->mixbuf, device->silence_value, device->buffer_size);
}
hidden->frame_size = device->spec.channels * (SDL_AUDIO_BITSIZE(device->spec.format) / 8);
hidden->semaphore = SDL_CreateSemaphore(0);
if (!hidden->semaphore) {
LOGI("SDL Failed SDL_CreateSemaphore %s iscapture:%d", SDL_GetError(), iscapture);
return -1;
}
res = ctx.AAudioStream_requestStart(hidden->stream);
if (res != AAUDIO_OK) {
@ -193,20 +216,42 @@ static int AAUDIO_OpenDevice(SDL_AudioDevice *device)
static void AAUDIO_CloseDevice(SDL_AudioDevice *device)
{
struct SDL_PrivateAudioData *hidden = device->hidden;
if (hidden) {
LOGI(__func__);
if (hidden) {
if (hidden->stream) {
ctx.AAudioStream_requestStop(hidden->stream);
// !!! FIXME: do we have to wait for the state to change to make sure all buffered audio has played, or will close do this (or will the system do this after the close)?
// !!! FIXME: also, will this definitely wait for a running data callback to finish, and then stop the callback from firing again?
ctx.AAudioStream_close(hidden->stream);
}
if (hidden->semaphore) {
SDL_DestroySemaphore(hidden->semaphore);
}
SDL_free(hidden->mixbuf);
SDL_free(hidden);
device->hidden = NULL;
}
}
// due to the way the aaudio data callback works, PlayDevice is a no-op. The callback collects audio while SDL camps in WaitDevice and
// fires a semaphore that will unblock WaitDevice and start a new iteration, so when the callback runs again, WaitDevice is ready
// to hand it more data.
static aaudio_data_callback_result_t AAUDIO_dataCallback(AAudioStream *stream, void *userData, void *audioData, int32_t numFrames)
{
SDL_AudioDevice *device = (SDL_AudioDevice *) userData;
SDL_assert(numFrames == device->sample_frames);
if (device->iscapture) {
SDL_memcpy(device->hidden->mixbuf, audioData, device->buffer_size);
} else {
SDL_memcpy(audioData, device->hidden->mixbuf, device->buffer_size);
}
SDL_PostSemaphore(device->hidden->semaphore);
return AAUDIO_CALLBACK_RESULT_CONTINUE;
}
static Uint8 *AAUDIO_GetDeviceBuf(SDL_AudioDevice *device, int *bufsize)
{
return device->hidden->mixbuf;
@ -214,44 +259,20 @@ static Uint8 *AAUDIO_GetDeviceBuf(SDL_AudioDevice *device, int *bufsize)
static void AAUDIO_WaitDevice(SDL_AudioDevice *device)
{
AAudioStream *stream = device->hidden->stream;
while (!SDL_AtomicGet(&device->shutdown) && ((int) ctx.AAudioStream_getBufferSizeInFrames(stream)) < device->sample_frames) {
SDL_Delay(1);
}
SDL_WaitSemaphore(device->hidden->semaphore);
}
static void AAUDIO_PlayDevice(SDL_AudioDevice *device, const Uint8 *buffer, int buflen)
{
AAudioStream *stream = device->hidden->stream;
const aaudio_result_t res = ctx.AAudioStream_write(stream, buffer, device->sample_frames, 0);
if (res < 0) {
LOGI("%s : %s", __func__, ctx.AAudio_convertResultToText(res));
} else {
LOGI("SDL AAudio play: %d frames, wanted:%d frames", (int)res, sample_frames);
}
#if 0
// Log under-run count
{
static int prev = 0;
int32_t cnt = ctx.AAudioStream_getXRunCount(hidden->stream);
if (cnt != prev) {
SDL_Log("AAudio underrun: %d - total: %d", cnt - prev, cnt);
prev = cnt;
}
}
#endif
// AAUDIO_dataCallback picks up our work and unblocks AAUDIO_WaitDevice.
}
// no need for a FlushCapture implementation, just don't read mixbuf until the next iteration.
static int AAUDIO_CaptureFromDevice(SDL_AudioDevice *device, void *buffer, int buflen)
{
const aaudio_result_t res = ctx.AAudioStream_read(device->hidden->stream, buffer, device->sample_frames, 0);
if (res < 0) {
LOGI("%s : %s", __func__, ctx.AAudio_convertResultToText(res));
return -1;
}
LOGI("SDL AAudio capture:%d frames, wanted:%d frames", (int)res, buflen / device->hidden->frame_size);
return res * device->hidden->frame_size;
const int cpy = SDL_min(buflen, device->buffer_size);
SDL_memcpy(buffer, device->hidden->mixbuf, cpy);
return cpy;
}
static void AAUDIO_Deinitialize(void)
@ -377,6 +398,7 @@ void AAUDIO_ResumeDevices(void)
}
}
// !!! FIXME: do we need this now that we use the callback?
/*
We can sometimes get into a state where AAudioStream_write() will just block forever until we pause and unpause.
None of the standard state queries indicate any problem in my testing. And the error callback doesn't actually get called.

16
src/audio/aaudio/SDL_aaudiofuncs.h
View File

@ -32,15 +32,15 @@ SDL_PROC(void, AAudioStreamBuilder_setFormat, (AAudioStreamBuilder * builder, aa
SDL_PROC_UNUSED(void, AAudioStreamBuilder_setSharingMode, (AAudioStreamBuilder * builder, aaudio_sharing_mode_t sharingMode))
SDL_PROC(void, AAudioStreamBuilder_setDirection, (AAudioStreamBuilder * builder, aaudio_direction_t direction))
SDL_PROC_UNUSED(void, AAudioStreamBuilder_setBufferCapacityInFrames, (AAudioStreamBuilder * builder, int32_t numFrames))
SDL_PROC_UNUSED(void, AAudioStreamBuilder_setPerformanceMode, (AAudioStreamBuilder * builder, aaudio_performance_mode_t mode))
SDL_PROC(void, AAudioStreamBuilder_setPerformanceMode, (AAudioStreamBuilder * builder, aaudio_performance_mode_t mode))
SDL_PROC_UNUSED(void, AAudioStreamBuilder_setUsage, (AAudioStreamBuilder * builder, aaudio_usage_t usage)) /* API 28 */
SDL_PROC_UNUSED(void, AAudioStreamBuilder_setContentType, (AAudioStreamBuilder * builder, aaudio_content_type_t contentType)) /* API 28 */
SDL_PROC_UNUSED(void, AAudioStreamBuilder_setInputPreset, (AAudioStreamBuilder * builder, aaudio_input_preset_t inputPreset)) /* API 28 */
SDL_PROC_UNUSED(void, AAudioStreamBuilder_setAllowedCapturePolicy, (AAudioStreamBuilder * builder, aaudio_allowed_capture_policy_t capturePolicy)) /* API 29 */
SDL_PROC_UNUSED(void, AAudioStreamBuilder_setSessionId, (AAudioStreamBuilder * builder, aaudio_session_id_t sessionId)) /* API 28 */
SDL_PROC_UNUSED(void, AAudioStreamBuilder_setPrivacySensitive, (AAudioStreamBuilder * builder, bool privacySensitive)) /* API 30 */
SDL_PROC_UNUSED(void, AAudioStreamBuilder_setDataCallback, (AAudioStreamBuilder * builder, AAudioStream_dataCallback callback, void *userData))
SDL_PROC_UNUSED(void, AAudioStreamBuilder_setFramesPerDataCallback, (AAudioStreamBuilder * builder, int32_t numFrames))
SDL_PROC(void, AAudioStreamBuilder_setDataCallback, (AAudioStreamBuilder * builder, AAudioStream_dataCallback callback, void *userData))
SDL_PROC(void, AAudioStreamBuilder_setFramesPerDataCallback, (AAudioStreamBuilder * builder, int32_t numFrames))
SDL_PROC(void, AAudioStreamBuilder_setErrorCallback, (AAudioStreamBuilder * builder, AAudioStream_errorCallback callback, void *userData))
SDL_PROC(aaudio_result_t, AAudioStreamBuilder_openStream, (AAudioStreamBuilder * builder, AAudioStream **stream))
SDL_PROC(aaudio_result_t, AAudioStreamBuilder_delete, (AAudioStreamBuilder * builder))
@ -52,14 +52,14 @@ SDL_PROC_UNUSED(aaudio_result_t, AAudioStream_requestFlush, (AAudioStream * stre
SDL_PROC(aaudio_result_t, AAudioStream_requestStop, (AAudioStream * stream))
SDL_PROC(aaudio_stream_state_t, AAudioStream_getState, (AAudioStream * stream))
SDL_PROC_UNUSED(aaudio_result_t, AAudioStream_waitForStateChange, (AAudioStream * stream, aaudio_stream_state_t inputState, aaudio_stream_state_t *nextState, int64_t timeoutNanoseconds))
SDL_PROC(aaudio_result_t, AAudioStream_read, (AAudioStream * stream, void *buffer, int32_t numFrames, int64_t timeoutNanoseconds))
SDL_PROC(aaudio_result_t, AAudioStream_write, (AAudioStream * stream, const void *buffer, int32_t numFrames, int64_t timeoutNanoseconds))
SDL_PROC_UNUSED(aaudio_result_t, AAudioStream_read, (AAudioStream * stream, void *buffer, int32_t numFrames, int64_t timeoutNanoseconds))
SDL_PROC_UNUSED(aaudio_result_t, AAudioStream_write, (AAudioStream * stream, const void *buffer, int32_t numFrames, int64_t timeoutNanoseconds))
SDL_PROC_UNUSED(aaudio_result_t, AAudioStream_setBufferSizeInFrames, (AAudioStream * stream, int32_t numFrames))
SDL_PROC(int32_t, AAudioStream_getBufferSizeInFrames, (AAudioStream * stream))
SDL_PROC_UNUSED(int32_t, AAudioStream_getBufferSizeInFrames, (AAudioStream * stream))
SDL_PROC_UNUSED(int32_t, AAudioStream_getFramesPerBurst, (AAudioStream * stream))
SDL_PROC(int32_t, AAudioStream_getBufferCapacityInFrames, (AAudioStream * stream))
SDL_PROC_UNUSED(int32_t, AAudioStream_getFramesPerDataCallback, (AAudioStream * stream))
SDL_PROC(int32_t, AAudioStream_getXRunCount, (AAudioStream * stream))
SDL_PROC(int32_t, AAudioStream_getFramesPerDataCallback, (AAudioStream * stream))
SDL_PROC_UNUSED(int32_t, AAudioStream_getXRunCount, (AAudioStream * stream))
SDL_PROC(int32_t, AAudioStream_getSampleRate, (AAudioStream * stream))
SDL_PROC(int32_t, AAudioStream_getChannelCount, (AAudioStream * stream))
SDL_PROC_UNUSED(int32_t, AAudioStream_getSamplesPerFrame, (AAudioStream * stream))