fix: amr_decoder 支持 audio/pcm 直通跳过 ffmpeg

src/router/xtc_recognize/amr_decoder.py

@@ -17,6 +17,7 @@ async def decode_to_pcm_s16le(
     duration_sec: int = 3,
     sample_rate: int = 8000,
     channels: int = 1,
+    mime: str = "",
 ) -> bytes:
     """把任意音频（amr/mp3/wav/m4a 等）转成 8kHz 单声道 PCM s16le。
 
@@ -25,6 +26,7 @@ async def decode_to_pcm_s16le(
         duration_sec: 截取时长（秒），默认 3
         sample_rate: 采样率，默认 8000（网易云 shazam_v2 要求）
         channels: 声道数，默认 1
+        mime: MIME 类型。若为 audio/pcm 则视为已是 PCM s16le 直接截断返回
 
     Returns:
         PCM s16le 字节流
@@ -32,6 +34,11 @@ async def decode_to_pcm_s16le(
     Raises:
         RuntimeError: ffmpeg 失败
     """
+    # 裸 PCM 直通（便于测试 / 手表若直接录 PCM 也支持）
+    if mime in ("audio/pcm", "audio/x-pcm", "application/pcm"):
+        needed = sample_rate * channels * 2 * duration_sec
+        return audio_bytes[:needed]
+
     args = [
         "ffmpeg",
         "-i", "pipe:0",
@@ -42,7 +49,7 @@ async def decode_to_pcm_s16le(
         "-t", str(duration_sec),
         "pipe:1",
     ]
-    logger.info("[amr-decoder] ffmpeg start, input=%d bytes", len(audio_bytes))
+    logger.info("[amr-decoder] ffmpeg start, input=%d bytes mime=%s", len(audio_bytes), mime)
 
     proc = await asyncio.create_subprocess_exec(
         *args,

src/router/xtc_recognize/recognize.py

@@ -33,7 +33,7 @@ async def recognize_from_audio(
     )
 
     # 1) 转码
-    pcm = await decode_to_pcm_s16le(audio_bytes, duration_sec=duration)
+    pcm = await decode_to_pcm_s16le(audio_bytes, duration_sec=duration, mime=mime)
 
     # 2) 指纹
     fp = await generate_fp(pcm)