diff --git a/lib/decoding/tch_f_decoder_impl.cc b/lib/decoding/tch_f_decoder_impl.cc
index 1680caa..a775391 100644
--- a/lib/decoding/tch_f_decoder_impl.cc
+++ b/lib/decoding/tch_f_decoder_impl.cc
@@ -57,6 +57,8 @@
             throw std::runtime_error("TCH/F Decoder: can't open file\n");
         }
 
+        const unsigned char amr_nb_magic[6] = { 0x23, 0x21, 0x41, 0x4d, 0x52, 0x0a };
+
         if (d_tch_mode == MODE_SPEECH_EFR)
         {
             fwrite(amr_nb_magic, 1, 6, d_speech_file);