add device select to audio settings

res/modules/internal/audio_input.lua

@@ -1,27 +1,43 @@
-local audio_input_tokens_store = {}
+local _base64_encode_urlsafe = base64.encode_urlsafe
+local _random_bytes = random.bytes
+local core_token = _base64_encode_urlsafe(_random_bytes(18))
+
+local audio_input_tokens_store = {[core_token] = "core"}
 audio.input = {}
 
 local _gui_confirm = gui.confirm
-local _base64_encode_urlsafe = base64.encode_urlsafe
-local _random_bytes = random.bytes
 local _debug_pack_by_frame = debug.get_pack_by_frame
 local _audio_fetch_input = audio.__fetch_input
 audio.__fetch_input = nil
 local MAX_FETCH = 44100 * 4
+local MAX_AMPLITUDE = 32768
 
 local total_fetch = Bytearray()
+local max_amplitude = 0.0
 
 function audio.__reset_fetch_buffer()
     total_fetch:clear()
+    max_amplitude = 0.0
 end
 
-function audio.fetch_input(token, size)
+function audio.input.get_max_amplitude()
+    return max_amplitude / MAX_AMPLITUDE
+end
+
+function audio.input.fetch_input(token, size)
     size = size or MAX_FETCH
     if audio_input_tokens_store[token] then
         if #total_fetch >= size then
             return total_fetch:slice(1, size)
         end
-        total_fetch:append(_audio_fetch_input(size - #total_fetch))
+        local fetched = _audio_fetch_input(size - #total_fetch)
+        if not fetched then
+            return
+        end
+        for i, sample in ipairs(I16view(fetched)) do
+            max_amplitude = math.max(math.abs(sample))
+        end
+        total_fetch:append(fetched)
         return total_fetch:slice()
     end
     error("access denied")
@@ -38,3 +54,10 @@ function audio.input.request_open(callback)
         menu:reset()
     end)
 end
+
+function audio.input.__get_core_token()
+    local caller = _debug_pack_by_frame(1)
+    if caller == "core" then
+        return core_token
+    end
+end