support ftypmp42 format

lib/src/parsers/mp4.dart

@@ -20,6 +20,9 @@ class BoxHeader {
   String type;
 
   BoxHeader(this.size, this.type);
+
+  @override
+  toString() => 'size: ${size}, type: ${type}';
 }
 
 final supportedBox = [
@@ -82,9 +85,13 @@ class MP4Parser extends TagParser {
 
       if (supportedBox.contains(box.type)) {
         await processBox(reader, box);
-      } else {
-        // We substract 8 to the box size because we already read the data for
+      } else if (box.type == "ftyp"){
+        // read 4 bytes brand name
+        reader.readSync(4);
+        // We substract 4 to the box size because we already read the data for
         // the box header
+        reader.setPositionSync(reader.positionSync() + box.size - 4);
+      } else {
         reader.setPositionSync(reader.positionSync() + box.size - 8);
       }
     }
@@ -125,16 +132,15 @@ class MP4Parser extends TagParser {
       final timeScale = getUint32(bytes.sublist(12, 16));
       final timeUnit = getUint32(bytes.sublist(16, 20));
 
-      tags.duration = Duration(seconds: timeUnit ~/ timeScale);
+      double microseconds = (timeUnit / timeScale) * 1000000;
+      tags.duration = Duration(microseconds: microseconds.toInt());
     } else if (box.type == "udta") {
       await parseRecurvise(reader, box);
     } else if (box.type == "ilst") {
       await parseRecurvise(reader, box);
     } else if (["trak", "mdia", "minf", "stbl", "stsd"].contains(box.type)) {
       await parseRecurvise(reader, box);
     } else if (box.type == "meta") {
-      reader.readSync(4);
-
       await parseRecurvise(reader, box);
     } else if (box.type[0] == "©" ||
         ["gnre", "trkn", "disk", "tmpo", "cpil", "too", "covr", "pgap", "gen"]
@@ -198,8 +204,7 @@ class MP4Parser extends TagParser {
 
       final name = await _readBox(reader);
 
-      final nameValue =
-          String.fromCharCodes(reader.readSync(name.size - 8).sublist(4));
+      final nameValue = String.fromCharCodes(reader.readSync(name.size - 8).sublist(4));
       final dataBox = await _readBox(reader);
       final data = reader.readSync(dataBox.size - 8);
       final finalValue = String.fromCharCodes(data.sublist(8));
@@ -233,6 +238,7 @@ class MP4Parser extends TagParser {
     // the `meta` box has 4 additional bytes that are not useful. We skip them
     if ("meta" == box.type) {
       offset += 4;
+      reader.readSync(4);
     } else if (box.type == "stsd") {
       offset += 8;
       reader.readSync(8);

test/mp4/mp4_test.dart

@@ -16,7 +16,7 @@ void main() {
     // expect(result.bitrate, equals(48000));
     expect(result.title, equals("Title"));
     expect(result.trackNumber, equals(1));
-    expect(result.duration, equals(Duration(seconds: 1)));
+    expect(result.duration, equals(Duration(microseconds: 1021333)));
     expect(result.totalDisc, equals(1));
     expect(result.lyrics, equals("Lyrics"));
     expect(result.trackTotal, equals(10));
@@ -33,4 +33,10 @@ void main() {
     expect(result.pictures.first.bytes,
         File("test/data/cover.png").readAsBytesSync());
   });
+  test("Parse MP4 file with ftypmp42 container without the cover", () async {
+    final track = File('./test/mp4/track_ftypmp42.m4a');
+    final result = await readMetadata(track, getImage: false);
+
+    expect(result.duration, equals(3392), reason: 'Wrong: Audio duration');
+  });
 }