avformat/daudenc: Return proper error codes instead if -1

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavformat/daudenc.c

@@ -25,7 +25,7 @@ static int daud_init(struct AVFormatContext *s)
 {
     AVCodecParameters *par = s->streams[0]->codecpar;
     if (par->channels!=6 || par->sample_rate!=96000)
-        return -1;
+        return AVERROR(EINVAL);
     return 0;
 }
 
@@ -34,7 +34,7 @@ static int daud_write_packet(struct AVFormatContext *s, AVPacket *pkt)
     if (pkt->size > 65535) {
         av_log(s, AV_LOG_ERROR,
                "Packet size too large for s302m. (%d > 65535)\n", pkt->size);
-        return -1;
+        return AVERROR_INVALIDDATA;
     }
     avio_wb16(s->pb, pkt->size);
     avio_wb16(s->pb, 0x8010); // unknown