streaming sounds triple buffer to avoid micro stutter

gamemaker/extensions/FAudioGMS/FAudioGMS.yy

@@ -55,8 +55,9 @@
             2,
             2,
           ],"resourceVersion":"1.0","name":"FAudioGMS_SetListenerPosition","tags":[],"resourceType":"GMExtensionFunction",},
-        {"externalName":"FAudioGMS_StreamingSound_LoadOGG","kind":1,"help":"FAudioGMS_StreamingSound_LoadOGG(filePath)","hidden":false,"returnType":2,"argCount":0,"args":[
+        {"externalName":"FAudioGMS_StreamingSound_LoadOGG","kind":1,"help":"FAudioGMS_StreamingSound_LoadOGG(filePath, bufferSizeInBytes)","hidden":false,"returnType":2,"argCount":0,"args":[
             1,
+            2,
           ],"resourceVersion":"1.0","name":"FAudioGMS_StreamingSound_LoadOGG","tags":[],"resourceType":"GMExtensionFunction",},
         {"externalName":"FAudioGMS_SoundInstance_SetPan","kind":1,"help":"FAudioGMS_SoundInstance_SetPan(soundInstanceID, pan)","hidden":false,"returnType":2,"argCount":0,"args":[
             2,

src/FAudioGMS.c

@@ -174,13 +174,19 @@ typedef struct FAudioGMS_StaticSound
     uint32_t lengthInSeconds;
 } FAudioGMS_StaticSound;
 
+/* if we don't triple buffer, we'll microstutter the voice while waiting for decode */
+#define STREAMING_BUFFER_COUNT 3 
+#define DEFAULT_STREAMING_BUFFER_SIZE 32768
+
 typedef struct FAudioGMS_StreamingSound
 {
     stb_vorbis *fileHandle;
     stb_vorbis_info info;
-    float *streamBuffer;
+    float *streamBuffer[STREAMING_BUFFER_COUNT];
     uint32_t streamBufferSize;
-    uint32_t mostRecentBufferOffset; /* used for calculating track position */
+    uint32_t nextStreamBufferIndex;  /* it's a ring buffer! */
+    uint32_t buffersLoadedCount;     /* how many buffers are we buffering? */
+    uint32_t mostRecentSampleOffset; /* used for calculating track position */
     uint8_t isFinalBuffer;           /* used to detect end of playback */
 } FAudioGMS_StreamingSound;
 
@@ -321,7 +327,7 @@ static inline FAudioGMS_EffectChain *FAudioGMS_INTERNAL_LookupEffectChain(uint32
 
 /* Forward declarations to avoid some annoying BS */
 
-static void FAudioGMS_INTERNAL_SoundInstance_AddBuffer(FAudioGMS_SoundInstance *instance);
+static void FAudioGMS_INTERNAL_SoundInstance_AddBuffers(FAudioGMS_SoundInstance *instance);
 static void FAudioGMS_INTERNAL_SoundInstance_Play(FAudioGMS_SoundInstance *instance);
 static void FAudioGMS_INTERNAL_SoundInstance_Stop(FAudioGMS_SoundInstance *instance);
 static void FAudioGMS_INTERNAL_SoundInstance_Destroy(FAudioGMS_SoundInstance *instance);
@@ -345,13 +351,22 @@ static void FAudioGMS_INTERNAL_OnBufferEndCallback(
     }
     else
     {
+        instance->soundData.streamingSound.buffersLoadedCount -= 1;
+        instance->soundData.streamingSound.mostRecentSampleOffset +=
+            instance->soundData.streamingSound.streamBufferSize /
+            (instance->format.nChannels * sizeof(float));
+
+        instance->soundData.streamingSound.mostRecentSampleOffset = SDL_min(
+            instance->soundData.streamingSound.mostRecentSampleOffset,
+            instance->playLength);
+
         if (instance->soundData.streamingSound.isFinalBuffer)
         {
             FAudioGMS_INTERNAL_SoundInstance_Stop(instance);
         }
         else
         {
-            FAudioGMS_INTERNAL_SoundInstance_AddBuffer(instance);
+            FAudioGMS_INTERNAL_SoundInstance_AddBuffers(instance);
         }
     }
 
@@ -971,9 +986,13 @@ static void FAudioGMS_INTERNAL_Apply3D(FAudioGMS_SoundInstance *instance)
         0);
 }
 
-static void FAudioGMS_INTERNAL_SoundInstance_AddBuffer(FAudioGMS_SoundInstance *instance)
+static void FAudioGMS_INTERNAL_SoundInstance_AddBuffers(FAudioGMS_SoundInstance *instance)
 {
-    uint32_t defaultRequestedSampleCount = instance->format.nSamplesPerSec / 10; /* FIXME: make this configurable */
+    uint32_t i;
+    for (i = 0; i < STREAMING_BUFFER_COUNT - instance->soundData.streamingSound.buffersLoadedCount; i += 1)
+    {
+        uint32_t defaultRequestedSampleCount = instance->soundData.streamingSound.streamBufferSize /
+                                               (instance->format.nChannels * sizeof(float));
         uint32_t requestedSampleCount = defaultRequestedSampleCount;
 
         if (instance->playLength != 0)
@@ -984,28 +1003,19 @@ static void FAudioGMS_INTERNAL_SoundInstance_AddBuffer(FAudioGMS_SoundInstance *
             requestedSampleCount = SDL_min(requestedSampleCount, distanceToEndPoint);
         }
 
-    uint32_t requiredStagingBufferSize =
-        requestedSampleCount * instance->format.nChannels * sizeof(float);
-    if (instance->soundData.streamingSound.streamBufferSize < requiredStagingBufferSize)
-    {
-        instance->soundData.streamingSound.streamBuffer =
-            SDL_realloc(instance->soundData.streamingSound.streamBuffer, requiredStagingBufferSize);
-        instance->soundData.streamingSound.streamBufferSize = requiredStagingBufferSize;
-    }
-
-    instance->soundData.streamingSound.mostRecentBufferOffset =
-        stb_vorbis_get_sample_offset(instance->soundData.streamingSound.fileHandle);
-
         /* NOTE: this function returns samples per channel, not total samples */
         uint32_t sampleCount = stb_vorbis_get_samples_float_interleaved(
             instance->soundData.streamingSound.fileHandle,
             instance->format.nChannels,
-        instance->soundData.streamingSound.streamBuffer,
+            instance->soundData.streamingSound
+                .streamBuffer[instance->soundData.streamingSound.nextStreamBufferIndex],
             requestedSampleCount * instance->format.nChannels);
 
         FAudioBuffer buffer;
         buffer.AudioBytes = sampleCount * instance->format.nChannels * sizeof(float);
-    buffer.pAudioData = (uint8_t *)instance->soundData.streamingSound.streamBuffer;
+        buffer.pAudioData =
+            (uint8_t *)instance->soundData.streamingSound
+                .streamBuffer[instance->soundData.streamingSound.nextStreamBufferIndex];
         buffer.PlayBegin = 0;
         buffer.PlayLength = sampleCount;
 
@@ -1030,12 +1040,19 @@ static void FAudioGMS_INTERNAL_SoundInstance_AddBuffer(FAudioGMS_SoundInstance *
                 instance->soundData.streamingSound.isFinalBuffer = 1;
             }
         }
+
+        instance->soundData.streamingSound.nextStreamBufferIndex =
+            (instance->soundData.streamingSound.nextStreamBufferIndex + 1) % STREAMING_BUFFER_COUNT;
+        instance->soundData.streamingSound.buffersLoadedCount += 1;
+    }
 }
 
-double FAudioGMS_StreamingSound_LoadOGG(char *filePath)
+double FAudioGMS_StreamingSound_LoadOGG(char *filePath, double bufferSizeInBytes)
 {
     RETURN_ON_NULL_DEVICE(-1.0)
+    uint32_t i;
     int error = 0;
+    uint32_t bufferSizeInBytesInt = (uint32_t)bufferSizeInBytes;
     stb_vorbis *fileHandle = stb_vorbis_open_filename(filePath, &error, NULL);
 
     if (error != 0)
@@ -1045,6 +1062,11 @@ double FAudioGMS_StreamingSound_LoadOGG(char *filePath)
         return -1;
     }
 
+    if (bufferSizeInBytesInt == 0)
+    {
+        bufferSizeInBytesInt = DEFAULT_STREAMING_BUFFER_SIZE; /* A reasonable default! */
+    }
+
     stb_vorbis_info info = stb_vorbis_get_info(fileHandle);
 
     FAudioGMS_SoundInstance *instance =
@@ -1052,14 +1074,20 @@ double FAudioGMS_StreamingSound_LoadOGG(char *filePath)
 
     instance->soundData.streamingSound.fileHandle = fileHandle;
     instance->soundData.streamingSound.info = info;
-    instance->soundData.streamingSound.streamBuffer = NULL;
+    for (i = 0; i < STREAMING_BUFFER_COUNT; i += 1)
-    instance->soundData.streamingSound.streamBufferSize = 0;
+    {
-    instance->soundData.streamingSound.mostRecentBufferOffset = 0;
+        instance->soundData.streamingSound.streamBuffer[i] = SDL_malloc(bufferSizeInBytesInt);
+    }
+
+    instance->soundData.streamingSound.streamBufferSize = bufferSizeInBytesInt;
+    instance->soundData.streamingSound.mostRecentSampleOffset = 0;
     instance->soundData.streamingSound.isFinalBuffer = 0;
+    instance->soundData.streamingSound.nextStreamBufferIndex = 0;
+    instance->soundData.streamingSound.buffersLoadedCount = 0;
 
     instance->playLength = stb_vorbis_stream_length_in_samples(fileHandle);
 
-    FAudioGMS_INTERNAL_SoundInstance_AddBuffer(instance);
+    FAudioGMS_INTERNAL_SoundInstance_AddBuffers(instance);
 
     return instance->id;
 }
@@ -1212,10 +1240,12 @@ static void FAudioGMS_INTERNAL_SoundInstance_Stop(FAudioGMS_SoundInstance *insta
 
         if (!instance->isStatic)
         {
+            instance->soundData.streamingSound.buffersLoadedCount = 0;
+
             stb_vorbis_seek(
                 instance->soundData.streamingSound.fileHandle,
                 instance->playBegin); /* back to the start */
-            FAudioGMS_INTERNAL_SoundInstance_AddBuffer(
+            FAudioGMS_INTERNAL_SoundInstance_AddBuffers(
                 instance); /* preload so we dont stutter on play */
         }
     }
@@ -1365,8 +1395,9 @@ void FAudioGMS_SoundInstance_SetTrackPositionInSeconds(
         }
         else
         {
+            instance->soundData.streamingSound.buffersLoadedCount = 0;
             stb_vorbis_seek(instance->soundData.streamingSound.fileHandle, sampleFrame);
-            FAudioGMS_INTERNAL_SoundInstance_AddBuffer(instance);
+            FAudioGMS_INTERNAL_SoundInstance_AddBuffers(instance);
         }
 
         if (currentState == SoundState_Playing)
@@ -1387,7 +1418,7 @@ static uint32_t FAudioGMS_INTERNAL_SoundInstance_GetTrackPositionInSampleFrames(
         }
         else
         {
-            return instance->soundData.streamingSound.mostRecentBufferOffset +
+            return instance->soundData.streamingSound.mostRecentSampleOffset +
                    instance->voice.handle->src.curBufferOffset;
         }
     }
@@ -1436,8 +1467,9 @@ void FAudioGMS_SoundInstance_SetPlayRegion(
             else if (!instance->isStatic)
             {
                 FAudioSourceVoice_FlushSourceBuffers(instance->voice.handle);
+                instance->soundData.streamingSound.buffersLoadedCount = 0;
                 stb_vorbis_seek(instance->soundData.streamingSound.fileHandle, instance->playBegin);
-                FAudioGMS_INTERNAL_SoundInstance_AddBuffer(instance);
+                FAudioGMS_INTERNAL_SoundInstance_AddBuffers(instance);
             }
         }
         else
@@ -1565,6 +1597,8 @@ void FAudioGMS_SetListenerVelocity(double xVelocity, double yVelocity, double zV
 
 static void FAudioGMS_INTERNAL_SoundInstance_Destroy(FAudioGMS_SoundInstance *instance)
 {
+    uint32_t i;
+
     if (instance != NULL)
     {
         device->soundInstances[instance->id] = NULL;
@@ -1576,7 +1610,10 @@ static void FAudioGMS_INTERNAL_SoundInstance_Destroy(FAudioGMS_SoundInstance *in
 
         if (!instance->isStatic)
         {
-            SDL_free(instance->soundData.streamingSound.streamBuffer);
+            for (i = 0; i < STREAMING_BUFFER_COUNT; i += 1)
+            {
+                SDL_free(instance->soundData.streamingSound.streamBuffer[i]);
+            }
             stb_vorbis_close(instance->soundData.streamingSound.fileHandle);
         }
         if (instance->is3D)

src/FAudioGMS.h

@@ -48,8 +48,10 @@ extern "C"
         double staticSoundID); /* returns a sound instance ID */
     FAUDIOGMSAPI void FAudioGMS_StaticSound_Destroy(double staticSoundID);
     
+    /* returns a sound instance ID */
     FAUDIOGMSAPI double FAudioGMS_StreamingSound_LoadOGG(
-        char *filepath); /* returns a sound instance ID */
+        char *filepath,
+        double bufferSizeInBytes); /* if 0 is passed we will use a sensible default*/
 
     FAUDIOGMSAPI void FAudioGMS_SoundInstance_Play(double soundInstanceID);
     FAUDIOGMSAPI void FAudioGMS_SoundInstance_Pause(double soundInstanceID);