MP4 : Support alternate way of storing multiple values [#290]

Zeugma440 · Dec 1, 2024 · bb23499 · bb23499
1 parent eba0364
commit bb23499
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Showing 3 changed files with 51 additions and 7 deletions.
diff --git a/ATL.unit-test/IO/MetaData/MP4.cs b/ATL.unit-test/IO/MetaData/MP4.cs
@@ -1190,6 +1190,7 @@ public void TagIO_RW_MP4_Multiple_Values()
         {
             new ConsoleLogger();
 
+            // == 1st variant : repetition of the same metadata structure
             string testFileLocation = TestUtils.CopyAsTempTestFile("MP4/multiple_artists.m4a");
             AudioDataManager theFile = new AudioDataManager(AudioDataIOFactory.GetInstance().GetFromPath(testFileLocation));
 
@@ -1210,6 +1211,30 @@ public void TagIO_RW_MP4_Multiple_Values()
             // Check if separated values are still intact after rewriting
             Assert.AreEqual("ArtistA" + ATL.Settings.InternalValueSeparator + "ArtistB" + ATL.Settings.InternalValueSeparator + "Demo", theFile.NativeTag.Artist);
 
+            if (Settings.DeleteAfterSuccess) File.Delete(testFileLocation);
+
+
+            // == 2nd variant : repetition of the 'data' atom inside one single field
+            testFileLocation = TestUtils.CopyAsTempTestFile("MP4/multiple_artists2.m4a");
+            theFile = new AudioDataManager(AudioDataIOFactory.GetInstance().GetFromPath(testFileLocation));
+
+            // Read
+            Assert.IsTrue(theFile.ReadFromFile(false, true));
+            Assert.IsNotNull(theFile.NativeTag);
+            Assert.IsTrue(theFile.NativeTag.Exists);
+
+            Assert.AreEqual("ArtistA" + ATL.Settings.InternalValueSeparator + "ArtistB" + ATL.Settings.InternalValueSeparator + "Demo2", theFile.NativeTag.Artist);
+
+            // Write
+            theTag = new TagHolder();
+            theTag.Title = "blah";
+
+            Assert.IsTrue(theFile.UpdateTagInFileAsync(theTag.tagData, MetaDataIOFactory.TagType.NATIVE).GetAwaiter().GetResult());
+            Assert.IsTrue(theFile.ReadFromFile(false, true));
+
+            // Check if separated values are still intact after rewriting
+            Assert.AreEqual("ArtistA" + ATL.Settings.InternalValueSeparator + "ArtistB" + ATL.Settings.InternalValueSeparator + "Demo2", theFile.NativeTag.Artist);
+
             // Get rid of the working copy
             if (Settings.DeleteAfterSuccess) File.Delete(testFileLocation);
         }

diff --git a/ATL.unit-test/Resources/MP4/multiple_artists2.m4a b/ATL.unit-test/Resources/MP4/multiple_artists2.m4a
diff --git a/ATL/AudioData/IO/MP4.cs b/ATL/AudioData/IO/MP4.cs
@@ -1449,7 +1449,31 @@ private void readTag(BinaryReader source, ReadTagParams readTagParams)
 
                 if (1 == dataClass) // UTF-8 Text
                 {
-                    values.Add(Encoding.UTF8.GetString(source.ReadBytes((int)metadataSize - 16)));
+                    uint strSize = metadataSize;
+                    long lastLocation;
+                    var currentData = new List<string>();
+
+                    do
+                    {
+                        int dataSize = Math.Max(0, (int)strSize - 16);
+                        if (dataSize > 0)
+                        {
+                            strData = Encoding.UTF8.GetString(source.ReadBytes((int)strSize - 16));
+                            currentData.Add(strData);
+                        }
+
+                        // Look for multiple values
+                        lastLocation = source.BaseStream.Position;
+                        strSize = navigateToAtom(source, "data");
+                        if (strSize > 0)
+                        {
+                            source.BaseStream.Seek(8, SeekOrigin.Current);
+                            metadataSize += strSize;
+                        }
+                    } while (strSize > 0);
+                    source.BaseStream.Seek(lastLocation, SeekOrigin.Begin);
+                    strData = string.Join(Settings.InternalValueSeparator, currentData);
+                    values.Add(strData);
                 }
                 else if (21 == dataClass) // int8-16-24-32
                 {
@@ -2051,23 +2075,18 @@ private void writeTextFrame(BinaryWriter writer, string frameCode, string text)
             {
                 string[] values = text.Split(Settings.InternalValueSeparator);
                 var first = true;
-                // Handle multiple values
+                // Handle multiple values = repeat the 'data' atom
                 foreach (string value in values)
                 {
                     if (0 == value.Length) continue;
                     if (first) first = false;
                     else
                     {
                         finalFramePos = writer.BaseStream.Position;
-                        writer.BaseStream.Seek(frameSizePos1, SeekOrigin.Begin);
-                        writer.Write(StreamUtils.EncodeBEUInt32(Convert.ToUInt32(finalFramePos - frameSizePos1)));
                         writer.BaseStream.Seek(frameSizePos2, SeekOrigin.Begin);
                         writer.Write(StreamUtils.EncodeBEUInt32(Convert.ToUInt32(finalFramePos - frameSizePos2)));
                         writer.BaseStream.Seek(finalFramePos, SeekOrigin.Begin);
 
-                        frameSizePos1 = writer.BaseStream.Position;
-                        writer.Write(0); // Frame size placeholder to be rewritten in a few lines
-                        writer.Write(Utils.Latin1Encoding.GetBytes(frameCode));
                         frameSizePos2 = writer.BaseStream.Position;
                         writer.Write(0); // Frame size placeholder to be rewritten in a few lines
                         writer.Write(Utils.Latin1Encoding.GetBytes("data"));