fix(audio): support WAVE_FORMAT_EXTENSIBLE PCM WAVs, normalizing them to standard PCM on upload

DeepDrftPublic/Interop/wavutils.ts

@@ -59,7 +59,24 @@ class WavUtils {
                 // PCM only. The server's WavOffsetService synthesises PCM-shaped headers,
                 // and AudioProcessor rejects non-PCM at upload — accepting Float here would
                 // hand the decoder a header/payload mismatch that surfaces as garbled audio.
-                if (audioFormat !== 1) {
+                // WAVE_FORMAT_EXTENSIBLE (0xFFFE) is accepted only when its SubFormat GUID is
+                // PCM; the sample data is then byte-identical to standard PCM and every PCM
+                // field sits at the same offset. The vault normalizes uploads to plain PCM, so
+                // this is belt-and-suspenders for any EXTENSIBLE header that reaches the client.
+                if (audioFormat === 0xFFFE) {
+                    // EXTENSIBLE needs the full extension: 16 base + 2 cbSize + 22 = 40 bytes.
+                    if (chunkSize < 40) {
+                        console.warn(`EXTENSIBLE fmt chunk too small: ${chunkSize} (need >= 40)`);
+                        return null;
+                    }
+                    // SubFormat GUID at chunkOffset + 8 + 24; first two LE bytes are the format
+                    // tag — 0x0001 == WAVE_FORMAT_PCM.
+                    const subFormatTag = view.getUint16(chunkOffset + 8 + 24, true);
+                    if (subFormatTag !== 1) {
+                        console.warn(`Unsupported EXTENSIBLE SubFormat: ${subFormatTag} (only PCM supported)`);
+                        return null;
+                    }
+                } else if (audioFormat !== 1) {
                     console.warn(`Unsupported audio format: ${audioFormat} (only PCM=1 supported)`);
                     return null;
                 }