mmf: return meaningful error codes

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavformat/mmf.c

@@ -71,7 +71,7 @@ static int mmf_write_header(AVFormatContext *s)
     rate = mmf_rate_code(s->streams[0]->codec->sample_rate);
     if(rate < 0) {
         av_log(s, AV_LOG_ERROR, "Unsupported sample rate %d, supported are 4000, 8000, 11025, 22050 and 44100\n", s->streams[0]->codec->sample_rate);
-        return -1;
+        return AVERROR(EINVAL);
     }
 
     ffio_wfourcc(pb, "MMMD");
@@ -193,7 +193,7 @@ static int mmf_read_header(AVFormatContext *s)
 
     tag = avio_rl32(pb);
     if (tag != MKTAG('M', 'M', 'M', 'D'))
-        return -1;
+        return AVERROR_INVALIDDATA;
     avio_skip(pb, 4); /* file_size */
 
     /* Skip some unused chunks that may or may not be present */
@@ -208,11 +208,11 @@ static int mmf_read_header(AVFormatContext *s)
     /* Tag = "ATRx", where "x" = track number */
     if ((tag & 0xffffff) == MKTAG('M', 'T', 'R', 0)) {
         av_log(s, AV_LOG_ERROR, "MIDI like format found, unsupported\n");
-        return -1;
+        return AVERROR_PATCHWELCOME;
     }
     if ((tag & 0xffffff) != MKTAG('A', 'T', 'R', 0)) {
         av_log(s, AV_LOG_ERROR, "Unsupported SMAF chunk %08x\n", tag);
-        return -1;
+        return AVERROR_PATCHWELCOME;
     }
 
     avio_r8(pb); /* format type */
@@ -221,7 +221,7 @@ static int mmf_read_header(AVFormatContext *s)
     rate = mmf_rate(params & 0x0f);
     if(rate  < 0) {
         av_log(s, AV_LOG_ERROR, "Invalid sample rate\n");
-        return -1;
+        return AVERROR_INVALIDDATA;
     }
     avio_r8(pb); /* wave base bit */
     avio_r8(pb); /* time base d */
@@ -239,7 +239,7 @@ static int mmf_read_header(AVFormatContext *s)
     /* Make sure it's followed by an Awa chunk, aka wave data */
     if ((tag & 0xffffff) != MKTAG('A', 'w', 'a', 0)) {
         av_log(s, AV_LOG_ERROR, "Unexpected SMAF chunk %08x\n", tag);
-        return -1;
+        return AVERROR_INVALIDDATA;
     }
     mmf->data_size = size;