vorbisenc: set quality to a reasonable default.

Fixed Ticket847
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/vorbisenc.c

@@ -1164,7 +1164,7 @@ static av_cold int vorbis_encode_init(AVCodecContext *avccontext)
     if (avccontext->flags & CODEC_FLAG_QSCALE)
         venc->quality = avccontext->global_quality / (float)FF_QP2LAMBDA / 10.;
     else
-        venc->quality = 0.03;
+        venc->quality = 8;
     venc->quality *= venc->quality;
 
     if ((ret = put_main_header(venc, (uint8_t**)&avccontext->extradata)) < 0)