From feea26496cbbd64efe3c5db937e39ec4502e6e65 Mon Sep 17 00:00:00 2001 From: David Reid Date: Wed, 28 Feb 2024 17:17:13 +1000 Subject: [PATCH] Update Steam Audio example. --- examples/engine_steamaudio.c | 31 ++++++++++++++++++------------- 1 file changed, 18 insertions(+), 13 deletions(-) diff --git a/examples/engine_steamaudio.c b/examples/engine_steamaudio.c index e9610ab4..71fdad6a 100644 --- a/examples/engine_steamaudio.c +++ b/examples/engine_steamaudio.c @@ -8,17 +8,11 @@ By implementing this as a node, it can be plugged into any position within the g channel count of this node is always stereo. Steam Audio requires fixed sized processing, the size of which must be specified at initialization -time of the IPLBinauralEffect and IPLHRTF objects. This creates a problem because the node graph -will at times need to break down processing into smaller chunks for it's internal processing. The -node graph internally will read into a temporary buffer which is then mixed into the final output -buffer. This temporary buffer is allocated on the stack and is a fixed size. However, variability -comes into play because the channel count of the node is variable. It's not safe to just blindly -process the effect with the frame count specified in miniaudio's node processing callback. Doing so -results in glitching. To work around this, this example is just setting the update size to a known -value that works (256). If it's set to something too big it'll exceed miniaudio's processing size -used by the node graph. Alternatively you could use some kind of intermediary cache which -accumulates input data until enough is available and then do the processing. Ideally, Steam Audio -would support variable sized updates which would avoid this whole mess entirely. +time of the IPLBinauralEffect and IPLHRTF objects. To ensure miniaudio and Steam Audio are +consistent, you must set the period size in the engine config to be consistent with the frame size +you specify in your IPLAudioSettings object. If for some reason you want the period size of the +engine to be different to that of your Steam Audio configuration, you'll need to implement a sort +of buffering solution to your node. */ #define MINIAUDIO_IMPLEMENTATION #include "../miniaudio.h" @@ -285,8 +279,16 @@ int main(int argc, char** argv) /* The engine needs to be initialized first. */ engineConfig = ma_engine_config_init(); - engineConfig.channels = CHANNELS; - engineConfig.sampleRate = SAMPLE_RATE; + engineConfig.channels = CHANNELS; + engineConfig.sampleRate = SAMPLE_RATE; + + /* + Steam Audio requires processing in fixed sized chunks. Setting the period size in the engine config will + ensure our updates happen in predicably sized chunks as required by Steam Audio. + + Note that the configuration of Steam Audio below (IPLAudioSettings) will use this variable to specify the + update size to ensure it remains consistent. + */ engineConfig.periodSizeInFrames = 256; result = ma_engine_init(&engineConfig, &g_engine); @@ -306,6 +308,9 @@ int main(int argc, char** argv) be documented. If this is for some kind of buffer management with FFT or something, then this need not be exposed to the public API. There should be no need for the public API to require a fixed sized update. + + It's important that this be set to the periodSizeInFrames specified in the engine config above. + This ensures updates on both the miniaudio side and the Steam Audio side are consistent. */ iplAudioSettings.frameSize = engineConfig.periodSizeInFrames;