Improve piano

src/audio/samples/README.md

@@ -2,15 +2,25 @@ Piano samples are Salamander Grand Piano V3 samples by Alexander Holm,
 transcoded from OGG Vorbis to AAC M4A for iOS browser playback and distributed
 under CC BY 3.0.
 
-Source package: @audio-samples/piano-velocity12
+Source packages:
+
+- @audio-samples/piano-velocity4
+- @audio-samples/piano-velocity8
+- @audio-samples/piano-velocity12
+- @audio-samples/piano-velocity16
+- @audio-samples/piano-release
+
 Source recording: https://archive.org/details/SalamanderGrandPianoV3
 License: https://creativecommons.org/licenses/by/3.0/
 
-Checked-in subset: velocity layer `v12`, every minor-third anchor from A0
-through C8: A, C, Dsharp, and Fsharp for octaves 1-7, plus A0, A7, and C8.
-The app derives MIDI values from those note names in `piano-samples.ts`.
+Checked-in subset: velocity layers `v4`, `v8`, `v12`, and `v16` at the
+available Salamander strike anchors, plus all 88 release samples. The strike
+anchors are A, C, Dsharp, and Fsharp for octaves 1-7, plus A0, A7, and C8.
+The app derives strike MIDI values and velocity layers from filenames in
+`piano-samples.ts`; release sample `rel1` maps to A0 and `rel88` maps to C8.
 
-Repro notes: start from the matching `v12` OGG files in the source package and
-transcode each selected sample to AAC/M4A without renaming the note/velocity
-stem. The expected output filenames are `<note>v12.m4a`, for example
-`C4v12.m4a`.
+Repro notes: start from the matching OGG files in the source packages and
+transcode each selected sample to AAC/M4A at 192 kbps without renaming the
+note/velocity or release stem. Replace `#` with `sharp` in filenames for URL
+compatibility. Expected output filenames include `<note>v<layer>.m4a`, for
+example `C4v16.m4a`, and `rel<index>.m4a`, for example `rel40.m4a`.