Add setting -sAUDIO_WORKLET_SUPPORT_AUDIO_PARAMS (#25357)

Add setting -sAUDIO_WORKLET_SUPPORT_AUDIO_PARAMS to allow disabling the
often unused AudioParams mechanism.

Author: juj

site/source/docs/tools_reference/settings_reference.rst

@@ -2511,6 +2511,18 @@ full documentation in site/source/docs/api_reference/wasm_audio_worklets.rst
 
 Default value: 0
 
+.. _audio_worklet_support_audio_params:
+
+AUDIO_WORKLET_SUPPORT_AUDIO_PARAMS
+==================================
+
+If true, enables utilizing k- and a-rate AudioParams based properties in
+Wasm Audio Worklet code. If false, AudioParams are not used. Set to false
+for a tiny improvement to code size and AudioWorklet CPU performance when
+audio synthesis is synchronized using custom WebAssembly Memory-based means.
+
+Default value: true
+
 .. _webaudio_debug:
 
 WEBAUDIO_DEBUG

src/audio_worklet.js

@@ -18,7 +18,11 @@ var instantiatePromise;
 
 if (ENVIRONMENT_IS_AUDIO_WORKLET) {
 
+#if AUDIO_WORKLET_SUPPORT_AUDIO_PARAMS
 function createWasmAudioWorkletProcessor(audioParams) {
+#else
+function createWasmAudioWorkletProcessor() {
+#endif
   class WasmAudioWorkletProcessor extends AudioWorkletProcessor {
     constructor(args) {
       super();
@@ -76,9 +80,11 @@ function createWasmAudioWorkletProcessor(audioParams) {
       stackRestore(oldStackPtr);
     }
 
+#if AUDIO_WORKLET_SUPPORT_AUDIO_PARAMS
     static get parameterDescriptors() {
       return audioParams;
     }
+#endif
 
     /**
      * Marshals all inputs and parameters to the Wasm memory on the thread's
@@ -87,7 +93,13 @@ function createWasmAudioWorkletProcessor(audioParams) {
      *
      * @param {Object} parameters
      */
+#if AUDIO_WORKLET_SUPPORT_AUDIO_PARAMS
     process(inputList, outputList, parameters) {
+#else
+    /** @suppress {checkTypes} */
+    process(inputList, outputList) {
+#endif
+
 #if ALLOW_MEMORY_GROWTH
       // Recreate the output views if the heap has changed
       // TODO: add support for GROWABLE_ARRAYBUFFERS
@@ -117,11 +129,13 @@ function createWasmAudioWorkletProcessor(audioParams) {
       }
       stackMemoryData += outputViewsNeeded * this.bytesPerChannel;
       var numParams = 0;
+#if AUDIO_WORKLET_SUPPORT_AUDIO_PARAMS
       for (entry in parameters) {
         ++numParams;
         stackMemoryStruct += {{{ C_STRUCTS.AudioParamFrame.__size__ }}};
         stackMemoryData += parameters[entry].byteLength;
       }
+#endif
       var oldStackPtr = stackSave();
 #if ASSERTIONS
       console.assert(oldStackPtr == this.ctorOldStackPtr, 'AudioWorklet stack address has unexpectedly moved');
@@ -158,6 +172,7 @@ function createWasmAudioWorkletProcessor(audioParams) {
         }
       }
 
+#if AUDIO_WORKLET_SUPPORT_AUDIO_PARAMS
       // Copy parameters descriptor structs and data to Wasm. 'paramsPtr' is the
       // start of the C callback's input AudioParamFrame.
       var /*const*/ paramsPtr = structPtr;
@@ -170,6 +185,9 @@ function createWasmAudioWorkletProcessor(audioParams) {
         HEAPF32.set(subentry, {{{ getHeapOffset('dataPtr', 'float') }}});
         dataPtr += subentry.length * {{{ getNativeTypeSize('float') }}};
       }
+#else
+      var paramsPtr = 0;
+#endif
 
       // Copy output audio descriptor structs to Wasm. 'outputsPtr' is the start
       // of the C callback's output AudioSampleFrame. 'dataPtr' will now be
@@ -261,7 +279,11 @@ class BootstrapMessages extends AudioWorkletProcessor {
         // '_wpn' is short for 'Worklet Processor Node', using an identifier
         // that will never conflict with user messages
         // Register a real AudioWorkletProcessor that will actually do audio processing.
+#if AUDIO_WORKLET_SUPPORT_AUDIO_PARAMS
         registerProcessor(d['_wpn'], createWasmAudioWorkletProcessor(d.audioParams));
+#else
+        registerProcessor(d['_wpn'], createWasmAudioWorkletProcessor());
+#endif
 #if WEBAUDIO_DEBUG
         console.log(`Registered a new WasmAudioWorkletProcessor "${d['_wpn']}" with AudioParams: ${d.audioParams}`);
 #endif

src/lib/libwebaudio.js

@@ -230,12 +230,13 @@ var LibraryWebAudio = {
     assert(EmAudio[contextHandle] instanceof (window.AudioContext || window.webkitAudioContext), `Called emscripten_create_wasm_audio_worklet_processor_async() on a context handle ${contextHandle} that is not an AudioContext, but of type ${typeof EmAudio[contextHandle]}`);
 #endif
 
-    var audioParams = [];
     var processorName = UTF8ToString({{{ makeGetValue('options', C_STRUCTS.WebAudioWorkletProcessorCreateOptions.name, '*') }}});
+
+#if AUDIO_WORKLET_SUPPORT_AUDIO_PARAMS
     var numAudioParams = {{{ makeGetValue('options', C_STRUCTS.WebAudioWorkletProcessorCreateOptions.numAudioParams, 'i32') }}};
     var audioParamDescriptors = {{{ makeGetValue('options', C_STRUCTS.WebAudioWorkletProcessorCreateOptions.audioParamDescriptors, '*') }}};
+    var audioParams = [];
     var paramIndex = 0;
-
     while (numAudioParams--) {
       audioParams.push({
         name: paramIndex++,
@@ -246,6 +247,10 @@ var LibraryWebAudio = {
       });
       audioParamDescriptors += {{{ C_STRUCTS.WebAudioParamDescriptor.__size__ }}};
     }
+#elif ASSERTIONS
+    var numAudioParams = {{{ makeGetValue('options', C_STRUCTS.WebAudioWorkletProcessorCreateOptions.numAudioParams, 'i32') }}};
+    assert(numAudioParams == 0 && "Rebuild with -sAUDIO_WORKLET_SUPPORT_AUDIO_PARAMS to utilize AudioParams");
+#endif
 
 #if WEBAUDIO_DEBUG
     console.log(`emscripten_create_wasm_audio_worklet_processor_async() creating a new AudioWorklet processor with name ${processorName}`);
@@ -257,7 +262,9 @@ var LibraryWebAudio = {
       // not get accidentally mixed with user submitted messages, the remainder
       // for space saving reasons, abbreviated from their variable names).
       '_wpn': processorName,
+#if AUDIO_WORKLET_SUPPORT_AUDIO_PARAMS
       audioParams,
+#endif
       contextHandle,
       callback,
       userData,

src/settings.js

@@ -1642,6 +1642,13 @@ var WASM_WORKERS = 0;
 // [link]
 var AUDIO_WORKLET = 0;
 
+// If true, enables utilizing k- and a-rate AudioParams based properties in
+// Wasm Audio Worklet code. If false, AudioParams are not used. Set to false
+// for a tiny improvement to code size and AudioWorklet CPU performance when
+// audio synthesis is synchronized using custom WebAssembly Memory-based means.
+// [link]
+var AUDIO_WORKLET_SUPPORT_AUDIO_PARAMS = true;
+
 // If true, enables deep debugging of Web Audio backend.
 // [link]
 var WEBAUDIO_DEBUG = 0;

test/codesize/audio_worklet_wasm.expected.js

@@ -31,21 +31,21 @@ if (r) {
                 this.K();
             }
             K() {
-                for (var c = C(), f = D(this.B.length * this.s) >> 2, g = this.B.length - 1; 0 <= g; g--) this.B[g] = E.subarray(f, f += this.u);
+                for (var c = C(), g = D(this.B.length * this.s) >> 2, f = this.B.length - 1; 0 <= f; f--) this.B[f] = E.subarray(g, g += this.u);
                 F(c);
             }
             static get parameterDescriptors() {
                 return e;
             }
-            process(c, f, g) {
-                var n = c.length, x = f.length, k, p, h = 12 * (n + x), l = 0;
+            process(c, g, f) {
+                var n = c.length, x = g.length, k, p, h = 12 * (n + x), l = 0;
                 for (k of c) l += k.length;
                 l *= this.s;
                 var G = 0;
-                for (k of f) G += k.length;
+                for (k of g) G += k.length;
                 l += G * this.s;
                 var O = 0;
-                for (k in g) ++O, h += 8, l += g[k].byteLength;
+                for (k in f) ++O, h += 8, l += f[k].byteLength;
                 var V = C(), B = h + l + 15 & -16;
                 h = D(B);
                 l = h + (B - l);
@@ -58,12 +58,12 @@ if (r) {
                     for (p of k) E.set(p, l >> 2), l += this.s;
                 }
                 c = h;
-                for (k = 0; p = g[k++]; ) H[h >> 2] = p.length, H[h + 4 >> 2] = l, h += 8, E.set(p, l >> 2), 
+                for (k = 0; p = f[k++]; ) H[h >> 2] = p.length, H[h + 4 >> 2] = l, h += 8, E.set(p, l >> 2), 
                 l += 4 * p.length;
-                g = h;
-                for (k of f) H[h >> 2] = k.length, H[h + 4 >> 2] = this.u, H[h + 8 >> 2] = l, h += 12, 
+                f = h;
+                for (k of g) H[h >> 2] = k.length, H[h + 4 >> 2] = this.u, H[h + 8 >> 2] = l, h += 12, 
                 l += this.s * k.length;
-                if (n = this.v(n, B, x, g, O, c, this.A)) for (k of f) for (p of k) p.set(this.B[--G]);
+                if (n = this.v(n, B, x, f, O, c, this.A)) for (k of g) for (p of k) p.set(this.B[--G]);
                 F(V);
                 return !!n;
             }
@@ -119,10 +119,10 @@ var L = [], M = a => {
     for (d = ""; a < e; ) {
         var c = b[a++];
         if (c & 128) {
-            var f = b[a++] & 63;
-            if (192 == (c & 224)) d += String.fromCharCode((c & 31) << 6 | f); else {
-                var g = b[a++] & 63;
-                c = 224 == (c & 240) ? (c & 15) << 12 | f << 6 | g : (c & 7) << 18 | f << 12 | g << 6 | b[a++] & 63;
+            var g = b[a++] & 63;
+            if (192 == (c & 224)) d += String.fromCharCode((c & 31) << 6 | g); else {
+                var f = b[a++] & 63;
+                c = 224 == (c & 240) ? (c & 15) << 12 | g << 6 | f : (c & 7) << 18 | g << 12 | f << 6 | b[a++] & 63;
                 65536 > c ? d += String.fromCharCode(c) : (c -= 65536, d += String.fromCharCode(55296 | c >> 10, 56320 | c & 1023));
             }
         } else d += String.fromCharCode(c);
@@ -140,19 +140,19 @@ var L = [], M = a => {
     P[++R] = a;
     return R;
 }, W = (a, b, e, d, c) => {
-    var f = e ? K[e + 4 >> 2] : 0;
+    var g = e ? K[e + 4 >> 2] : 0;
     if (e) {
-        var g = K[e >> 2];
+        var f = K[e >> 2];
         e = H[e + 8 >> 2];
-        var n = f;
+        var n = g;
         if (e) {
             e >>= 2;
             for (var x = []; n--; ) x.push(H[e++]);
             e = x;
         } else e = void 0;
         d = {
-            numberOfInputs: g,
-            numberOfOutputs: f,
+            numberOfInputs: f,
+            numberOfOutputs: g,
             outputChannelCount: e,
             processorOptions: {
                 v: d,
@@ -165,18 +165,18 @@ var L = [], M = a => {
     P[++R] = a;
     return R;
 }, aa = (a, b, e, d) => {
-    var c = [], f = (f = H[b >> 2]) ? T(f) : "", g = K[b + 4 >> 2];
+    var c = (c = H[b >> 2]) ? T(c) : "", g = K[b + 4 >> 2];
     b = H[b + 8 >> 2];
-    for (var n = 0; g--; ) c.push({
+    for (var f = [], n = 0; g--; ) f.push({
         name: n++,
         defaultValue: E[b >> 2],
         minValue: E[b + 4 >> 2],
         maxValue: E[b + 8 >> 2],
         automationRate: (K[b + 12 >> 2] ? "k" : "a") + "-rate"
     }), b += 16;
     P[a].audioWorklet.D.port.postMessage({
-        _wpn: f,
-        H: c,
+        _wpn: c,
+        H: f,
         I: a,
         v: e,
         A: d
@@ -186,12 +186,12 @@ var L = [], M = a => {
     var b = a._wsc;
     b && A.get(b)(...a.C);
 }, ea = (a, b, e, d, c) => {
-    var f = P[a], g = f.audioWorklet, n = () => {
+    var g = P[a], f = g.audioWorklet, n = () => {
         A.get(d)(a, 0, c);
     };
-    if (!g) return n();
-    g.addModule(m.js).then((() => {
-        g.D = new AudioWorkletNode(f, "em-bootstrap", {
+    if (!f) return n();
+    f.addModule(m.js).then((() => {
+        f.D = new AudioWorkletNode(g, "em-bootstrap", {
             processorOptions: {
                 N: ca++,
                 G: m.wasm,
@@ -200,7 +200,7 @@ var L = [], M = a => {
                 F: e
             }
         });
-        g.D.port.onmessage = da;
+        f.D.port.onmessage = da;
         A.get(d)(a, 1, c);
     })).catch(n);
 };

test/test_browser.py

@@ -5459,6 +5459,7 @@ def test_full_js_library_strict(self):
     'pthreads_es6': (['-pthread', '-sPTHREAD_POOL_SIZE=2', '-sEXPORT_ES6'],),
     'es6': (['-sEXPORT_ES6'],),
     'strict': (['-sSTRICT'],),
+    'audio_params_disabled': (['-sAUDIO_WORKLET_SUPPORT_AUDIO_PARAMS=0'],),
   })
   @requires_sound_hardware
   def test_audio_worklet(self, args):