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Migrate the WebAudio backend over to the new callback system.

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This changes a few things for custom backends and the calculation of
the size of the buffer. See the custom_backend example.
This commit is contained in:
David Reid
2020-11-17 20:43:29 +10:00
parent dd9beefef4
commit 7fd98209ef
2 changed files with 183 additions and 163 deletions
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examples/custom_backend.c
+32 -8
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@@ -334,7 +334,7 @@ void ma_audio_callback_playback__sdl(void* pUserData, ma_uint8* pBuffer, int buf
ma_device_handle_backend_data_callback((ma_device*)pDeviceEx, pBuffer, NULL, (ma_uint32)bufferSizeInBytes / ma_get_bytes_per_frame(pDeviceEx->device.capture.internalFormat, pDeviceEx->device.capture.internalChannels));
}
static ma_result ma_device_init_internal__sdl(ma_device_ex* pDeviceEx, ma_device_type deviceType, ma_device_descriptor* pDescriptor)
static ma_result ma_device_init_internal__sdl(ma_device_ex* pDeviceEx, const ma_device_config* pConfig, ma_device_descriptor* pDescriptor)
{
ma_context_ex* pContextEx = (ma_context_ex*)pDeviceEx->device.pContext;
MA_SDL_AudioSpec desiredSpec;
@@ -355,8 +355,32 @@ static ma_result ma_device_init_internal__sdl(ma_device_ex* pDeviceEx, ma_device
pDescriptor->sampleRate = MA_DEFAULT_SAMPLE_RATE;
}
/*
When determining the period size, you need to take defaults into account. This is how the size of the period should be determined.
1) If periodSizeInFrames is not 0, use periodSizeInFrames; else
2) If periodSizeInMilliseconds is not 0, use periodSizeInMilliseconds; else
3) If both periodSizeInFrames and periodSizeInMilliseconds is 0, use the backend's default. If the backend does not allow a default
buffer size, use a default value of MA_DEFAULT_PERIOD_SIZE_IN_MILLISECONDS_LOW_LATENCY or
MA_DEFAULT_PERIOD_SIZE_IN_MILLISECONDS_CONSERVATIVE depending on the value of pConfig->performanceProfile.
Note that options 2 and 3 require knowledge of the sample rate in order to convert it to a frame count. You should try to keep the
calculation of the period size as accurate as possible, but sometimes it's just not practical so just use whatever you can.
*/
if (pDescriptor->periodSizeInFrames == 0) {
pDescriptor->periodSizeInFrames = ma_calculate_buffer_size_in_frames_from_milliseconds(pDescriptor->periodSizeInMilliseconds, pDescriptor->sampleRate);
if (pDescriptor->periodSizeInMilliseconds == 0) {
/* The default period size has been requested. I don't think SDL has an API to retrieve this, so just using defaults defined by miniaudio. */
if (pConfig->performanceProfile == ma_performance_profile_low_latency) {
pDescriptor->periodSizeInFrames = ma_calculate_buffer_size_in_frames_from_milliseconds(MA_DEFAULT_PERIOD_SIZE_IN_MILLISECONDS_LOW_LATENCY, pDescriptor->sampleRate);
} else {
pDescriptor->periodSizeInFrames = ma_calculate_buffer_size_in_frames_from_milliseconds(MA_DEFAULT_PERIOD_SIZE_IN_MILLISECONDS_CONSERVATIVE, pDescriptor->sampleRate);
}
} else {
/* An explicit period size in milliseconds was specified. */
pDescriptor->periodSizeInFrames = ma_calculate_buffer_size_in_frames_from_milliseconds(pDescriptor->periodSizeInMilliseconds, pDescriptor->sampleRate);
}
} else {
/* Nothing to do here. An explicit period size in frames was specified. */
}
/* SDL wants the buffer size to be a power of 2 for some reason. */
@@ -373,7 +397,7 @@ static ma_result ma_device_init_internal__sdl(ma_device_ex* pDeviceEx, ma_device
desiredSpec.format = ma_format_to_sdl(pDescriptor->format);
desiredSpec.channels = (ma_uint8)pDescriptor->channels;
desiredSpec.samples = (ma_uint16)pDescriptor->periodSizeInFrames;
desiredSpec.callback = (deviceType == ma_device_type_capture) ? ma_audio_callback_capture__sdl : ma_audio_callback_playback__sdl;
desiredSpec.callback = (pConfig->deviceType == ma_device_type_capture) ? ma_audio_callback_capture__sdl : ma_audio_callback_playback__sdl;
desiredSpec.userdata = pDeviceEx;
/* We'll fall back to f32 if we don't have an appropriate mapping between SDL and miniaudio. */
@@ -383,15 +407,15 @@ static ma_result ma_device_init_internal__sdl(ma_device_ex* pDeviceEx, ma_device
pDeviceName = NULL;
if (pDescriptor->pDeviceID != NULL) {
pDeviceName = ((MA_PFN_SDL_GetAudioDeviceName)pContextEx->sdl.SDL_GetAudioDeviceName)(pDescriptor->pDeviceID->custom.i, (deviceType == ma_device_type_playback) ? 0 : 1);
pDeviceName = ((MA_PFN_SDL_GetAudioDeviceName)pContextEx->sdl.SDL_GetAudioDeviceName)(pDescriptor->pDeviceID->custom.i, (pConfig->deviceType == ma_device_type_playback) ? 0 : 1);
}
deviceID = ((MA_PFN_SDL_OpenAudioDevice)pContextEx->sdl.SDL_OpenAudioDevice)(pDeviceName, (deviceType == ma_device_type_playback) ? 0 : 1, &desiredSpec, &obtainedSpec, MA_SDL_AUDIO_ALLOW_ANY_CHANGE);
deviceID = ((MA_PFN_SDL_OpenAudioDevice)pContextEx->sdl.SDL_OpenAudioDevice)(pDeviceName, (pConfig->deviceType == ma_device_type_playback) ? 0 : 1, &desiredSpec, &obtainedSpec, MA_SDL_AUDIO_ALLOW_ANY_CHANGE);
if (deviceID == 0) {
return ma_post_error((ma_device*)pDeviceEx, MA_LOG_LEVEL_ERROR, "Failed to open SDL2 device.", MA_FAILED_TO_OPEN_BACKEND_DEVICE);
}
if (deviceType == ma_device_type_playback) {
if (pConfig->deviceType == ma_device_type_playback) {
pDeviceEx->sdl.deviceIDPlayback = deviceID;
} else {
pDeviceEx->sdl.deviceIDCapture = deviceID;
@@ -422,14 +446,14 @@ static ma_result ma_device_init__sdl(ma_device* pDevice, const ma_device_config*
}
if (pConfig->deviceType == ma_device_type_capture || pConfig->deviceType == ma_device_type_duplex) {
result = ma_device_init_internal__sdl(pDeviceEx, ma_device_type_capture, pDescriptorCapture);
result = ma_device_init_internal__sdl(pDeviceEx, pConfig, pDescriptorCapture);
if (result != MA_SUCCESS) {
return result;
}
}
if (pConfig->deviceType == ma_device_type_playback || pConfig->deviceType == ma_device_type_duplex) {
result = ma_device_init_internal__sdl(pDeviceEx, ma_device_type_playback, pDescriptorPlayback);
result = ma_device_init_internal__sdl(pDeviceEx, pConfig, pDescriptorPlayback);
if (result != MA_SUCCESS) {
if (pConfig->deviceType == ma_device_type_duplex) {
((MA_PFN_SDL_CloseAudioDevice)pContextEx->sdl.SDL_CloseAudioDevice)(pDeviceEx->sdl.deviceIDCapture);