dvd: check for empty DVD volume ID

The only DVD sample I have just returns an empty string for this. Let
command.c use the filename if the ID is empty.

1 files changed, 4 insertions, 2 deletions

diff --git a/stream/stream_dvd.c b/stream/stream_dvd.c
index 7e3c9c1cc3..3dc7e76cc3 100644
--- a/stream/stream_dvd.c
+++ b/stream/stream_dvd.c
@@ -730,8 +730,10 @@ static int control(stream_t *stream,int cmd,void* arg)
         case STREAM_CTRL_GET_DVD_VOLUME_ID:
         {
             char buffer[128];
-            if (DVDUDFVolumeInfo(d->dvd, buffer, sizeof(buffer), NULL, 0) < 0
-                    && DVDISOVolumeInfo(d->dvd, buffer, sizeof(buffer), NULL, 0) < 0)
+            if (DVDUDFVolumeInfo(d->dvd, buffer, sizeof(buffer), NULL, 0) < 0 &&
+                DVDISOVolumeInfo(d->dvd, buffer, sizeof(buffer), NULL, 0) < 0)
+                return STREAM_ERROR;
+            if (!buffer[0])
                 return STREAM_ERROR;
             *(char**)arg = talloc_strdup(NULL, buffer);
             return STREAM_OK;