fix MODFORM-39

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@16999 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/formats/mod_sndfile/mod_sndfile.c

@@ -145,6 +145,7 @@ static switch_status_t sndfile_file_open(switch_file_handle_t *handle, const cha
 		context->sfinfo.samplerate = 8000;
 	} else if (!strcmp(ext, "adpcm")) {
 		context->sfinfo.format = SF_FORMAT_WAV | SF_FORMAT_IMA_ADPCM;
+		context->sfinfo.channels = 1;
 		context->sfinfo.samplerate = 8000;
 	}