Adjust probing priorities. Large ID3 tags make it impossible to detec…

…t content, so assume these files are MP3.

src/ffaudio/ffaudio-core.c

@@ -690,7 +690,6 @@ AUD_INPUT_PLUGIN
     .extensions = ffaudio_fmts,
     .update_song_tuple = ffaudio_write_tag,
 
-    /* FFMPEG probing takes forever on network files, so try everything else
-     * first. -jlindgren */
+    /* lowest priority fallback */
     .priority = 10,
 )

src/mpg123/mpg123.c

@@ -101,10 +101,28 @@ static bool_t mpg123_probe_for_fd (const char * fname, VFSFile * file)
 	if (! strncmp (fname, "mms://", 6))
 		return FALSE;
 
+	bool_t is_streaming = vfs_is_streaming (file);
+
+	/* Some MP3s begin with enormous ID3 tags, which fill up the whole probe
+	 * buffer and thus hide any MP3 content.  As a workaround, assume that an
+	 * ID3 tag means an MP3 file.  --jlindgren */
+	if (! is_streaming)
+	{
+		char id3buf[3];
+		if (vfs_fread (id3buf, 1, 3, file) != 3)
+			return FALSE;
+
+		if (! memcmp (id3buf, "ID3", 3))
+			return TRUE;
+
+		if (vfs_fseek (file, 0, SEEK_SET) < 0)
+			return FALSE;
+	}
+
 	mpg123_handle * dec = mpg123_new (NULL, NULL);
 	mpg123_param (dec, MPG123_ADD_FLAGS, MPG123_QUIET, 0);
 
-	if (vfs_is_streaming (file))
+	if (is_streaming)
 		mpg123_replace_reader_handle (dec, replace_read, replace_lseek_dummy, NULL);
 	else
 		mpg123_replace_reader_handle (dec, replace_read, replace_lseek, NULL);

src/sid/xmms-sid.c

@@ -431,5 +431,8 @@ AUD_INPUT_PLUGIN
     .probe_for_tuple = xs_probe_for_tuple,
 
     .extensions = xs_sid_fmts,          /* File ext assist */
-    .have_subtune = TRUE
+    .have_subtune = TRUE,
+
+    /* medium priority (slow to initialize) */
+    .priority = 5,
 )

src/sndfile/plugin.c

@@ -442,4 +442,7 @@ AUD_INPUT_PLUGIN
     .is_our_file_from_vfs = is_our_file_from_vfs,
     .extensions = sndfile_fmts,
     .mseek = file_mseek,
+
+    /* low priority fallback (but before ffaudio) */
+    .priority = 9,
 )

src/vorbis/vorbis.c

@@ -586,6 +586,6 @@ AUD_INPUT_PLUGIN
     .extensions = vorbis_fmts,
     .mimes = mimes,
 
-    /* Vorbis probing is a bit slow; check for MP3 and AAC first. -jlindgren */
+    /* medium-high priority (a little slow) */
     .priority = 2,
 )