make has_codec_parameters not returning true when sample_fmt is not set

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@15043 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavformat/utils.c

@@ -1842,7 +1842,7 @@ static int has_codec_parameters(AVCodecContext *enc)
     int val;
     switch(enc->codec_type) {
     case CODEC_TYPE_AUDIO:
-        val = enc->sample_rate && enc->channels;
+        val = enc->sample_rate && enc->channels && enc->sample_fmt != SAMPLE_FMT_NONE;
         if(!enc->frame_size &&
            (enc->codec_id == CODEC_ID_VORBIS ||
             enc->codec_id == CODEC_ID_AAC))