fix(audio): 修复在没有高音质模块时，回退播放实时音频流产生刺耳噪音及可能导致卡死的问题

station_broadcast.lua

@@ -1296,6 +1296,21 @@ local function decodePcmS8Chunk(chunk)
     return samples
 end
 
+local function decodePcmS16LEChunk(chunk)
+    if type(chunk) ~= "string" or #chunk < 2 then return nil end
+    local samples = {}
+    local idx = 1
+    for i = 2, #chunk, 2 do
+        local b = string.byte(chunk, i)
+        if b >= 128 then
+            b = b - 256
+        end
+        samples[idx] = b
+        idx = idx + 1
+    end
+    return samples
+end
+
 local function readU16LE(data, offset)
     local a, b = string.byte(data, offset, offset + 1)
     if not a or not b then return nil end
@@ -1684,6 +1699,41 @@ function Audio.playPcmItem(item)
     end
 end
 
+function Audio.playPcmS16LEItem(item)
+    if not Peripherals.speakers or #Peripherals.speakers == 0 then
+        Utils.log("WARN", "No speakers found; cannot play audio")
+        return
+    end
+
+    local playSeq = State.interruptSeq
+    local source = item.audioData
+
+    if type(source) == "table" and source.read then
+        source = source.read
+    end
+
+    if type(source) ~= "function" then
+        local data = source
+        source = function()
+            local chunk = data
+            data = nil
+            return chunk
+        end
+    end
+
+    while true do
+        if shouldStop(playSeq) then break end
+        local chunk = source()
+        if chunk == nil then break end
+        if type(chunk) == "string" and #chunk > 0 then
+            local samples = decodePcmS16LEChunk(chunk)
+            if samples and not playChunkOnSpeakers(samples, CONFIG.AUDIO_VOLUME, playSeq) then
+                break
+            end
+        end
+    end
+end
+
 function Audio.playWavStreamItem(item)
     if not Peripherals.speakers or #Peripherals.speakers == 0 then
         Utils.log("WARN", "No speakers found; cannot play audio")
@@ -1788,7 +1838,7 @@ function Audio.playItem(item)
         if success == false then
             format = tostring(item.audioFormat or "file"):lower()
             Utils.log("WARN", "HQ speaker playback failed, falling back to default decoding for format: " .. format)
-            if format == "wav" or format == "file" then
+            if format == "wav" or format == "file" or format == "stream" then
                 return Audio.playWavStreamItem(item)
             elseif format == "dfpwm" then
                 return Audio.playDfpwmItem(item)
@@ -1800,8 +1850,8 @@ function Audio.playItem(item)
         return success
     elseif format == "pcm" then
         return Audio.playPcmItem(item)
-    elseif format == "wav-stream" then
-        return Audio.playWavStreamItem(item)
+    elseif format == "wav-stream" or format == "wav-stream-live" then
+        return Audio.playPcmS16LEItem(item)
     end
     return Audio.playDfpwmItem(item)
 end