diff --git a/dom/media/webcodecs/AudioData.cpp b/dom/media/webcodecs/AudioData.cpp
index ac26ae445a300..aed3c3bf9ebf8 100644
--- a/dom/media/webcodecs/AudioData.cpp
+++ b/dom/media/webcodecs/AudioData.cpp
@@ -280,9 +280,6 @@ struct CopyToSpec {
   const uint32_t mFrameOffset;
   const uint32_t mPlaneIndex;
   const AudioSampleFormat mFormat;
-  // False if this is used internally, and this copy call doesn't come from
-  // script.
-  DebugOnly<bool> mFromScript = true;
 };
 
 bool IsInterleaved(const AudioSampleFormat& aFormat) {
@@ -435,7 +432,6 @@ void CopySamples(Span<S> aSource, Span<D> aDest, uint32_t aSourceChannelCount,
   }
 
   if (!IsInterleaved(aSourceFormat) && IsInterleaved(aCopyToSpec.mFormat)) {
-    MOZ_ASSERT(!aCopyToSpec.mFromScript);
     // Planar to interleaved -- copy of all channels of the source into the
     // destination buffer.
     MOZ_ASSERT(aCopyToSpec.mPlaneIndex == 0);
@@ -722,9 +718,6 @@ RefPtr<mozilla::AudioData> AudioData::ToAudioData() const {
                         storageNeeded.value());
 
   CopyToSpec spec(mNumberOfFrames, 0, 0, AudioSampleFormat::F32);
-#ifdef DEBUG
-  spec.mFromScript = false;
-#endif
 
   DoCopy(data, storage, mNumberOfChannels, mAudioSampleFormat.value(), spec);
 
diff --git a/dom/media/webcodecs/crashtests/1907438.html b/dom/media/webcodecs/crashtests/1907438.html
new file mode 100644
index 0000000000000..0f899b6d624e4
--- /dev/null
+++ b/dom/media/webcodecs/crashtests/1907438.html
@@ -0,0 +1,16 @@
+<script>
+  let a = new ArrayBuffer(4096);
+  let b = new AudioData({
+  "format": "s16-planar",
+  "sampleRate": 2.75e+38,
+  "numberOfFrames": 88,
+  "numberOfChannels": 20,
+  "timestamp": 97.5,
+  "data": a,
+  }):
+  let c = new Uint8ClampedArray(61932);
+  b.copyTo(c, {
+  "planeIndex": 0,
+  "format": "s16"
+  });
+</script>
diff --git a/dom/media/webcodecs/crashtests/crashtests.list b/dom/media/webcodecs/crashtests/crashtests.list
index 113abcc561f13..790cb2af96a3e 100644
--- a/dom/media/webcodecs/crashtests/crashtests.list
+++ b/dom/media/webcodecs/crashtests/crashtests.list
@@ -8,3 +8,4 @@ skip-if(Android) pref(dom.media.webcodecs.enabled,true) pref(media.ffmpeg.encode
 skip-if(Android) pref(dom.media.webcodecs.enabled,true) pref(media.ffmpeg.encoder.enabled,true) load 1897631.html
 skip-if(Android) pref(dom.media.webcodecs.enabled,true) load 1902555.html
 skip-if(Android) pref(dom.media.webcodecs.enabled,true) load 1905399.html
+skip-if(Android) pref(dom.media.webcodecs.enabled,true) load 1907438.html
diff --git a/testing/web-platform/tests/webcodecs/audio-data.any.js b/testing/web-platform/tests/webcodecs/audio-data.any.js
index d5d950647767b..67fef3c83c858 100644
--- a/testing/web-platform/tests/webcodecs/audio-data.any.js
+++ b/testing/web-platform/tests/webcodecs/audio-data.any.js
@@ -192,6 +192,7 @@ const TEST_TEMPLATE = {
   // For each test, copy this template and replace the number by the appropriate
   // number for this type
   testInput: [MIN, BIAS, MAX, MIN, HALF, NEGATIVE_HALF, BIAS, MAX, BIAS, BIAS],
+  testInterleavedResult: [MIN, NEGATIVE_HALF, BIAS, BIAS, MAX, MAX, MIN, BIAS, HALF, BIAS],
   testVectorInterleavedResult: [
     [MIN, MAX, HALF, BIAS, BIAS],
     [BIAS, MIN, NEGATIVE_HALF, MAX, BIAS],
@@ -274,6 +275,10 @@ function get_type_values(type) {
     cloned.testInput,
     idx => TEST_VALUES[type][idx]
   );
+  cloned.testInterleavedResult = Array.from(
+    cloned.testInterleavedResult,
+    idx => TEST_VALUES[type][idx]
+  );
   cloned.testVectorInterleavedResult = Array.from(
     cloned.testVectorInterleavedResult,
     c => {
@@ -418,7 +423,15 @@ function conversionTest(sourceType, destinationType) {
       "planar channel 1",
       assert_func
     );
-    // Planar to interleaved isn't supported
+    // Copy to interleaved from planar: all channels are copied
+    data.copyTo(destInterleaved, {planeIndex: 0, format: destinationType});
+    check_array_equality(
+      destInterleaved,
+      result.testInterleavedResult,
+      sourceType,
+      "planar to interleaved",
+      assert_func
+    );
   }, `Test conversion of ${sourceType} to ${destinationType}`);
 }