Extract shownotes from id3 comment field

core/src/main/java/de/danoeh/antennapod/core/feed/LocalFeedUpdater.java

@@ -4,11 +4,13 @@ import android.content.Context;
 import android.media.MediaMetadataRetriever;
 import android.net.Uri;
 import android.text.TextUtils;
+import android.util.Log;
 
 import androidx.annotation.NonNull;
 import androidx.documentfile.provider.DocumentFile;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
@@ -34,8 +36,12 @@ import de.danoeh.antennapod.model.feed.FeedMedia;
 import de.danoeh.antennapod.model.feed.FeedPreferences;
 import de.danoeh.antennapod.model.playback.MediaType;
 import de.danoeh.antennapod.parser.feed.util.MimeTypeUtils;
+import de.danoeh.antennapod.parser.media.id3.ID3ReaderException;
+import de.danoeh.antennapod.parser.media.id3.Id3MetadataReader;
+import org.apache.commons.io.input.CountingInputStream;
 
 public class LocalFeedUpdater {
+    private static final String TAG = "LocalFeedUpdater";
 
     static final String[] PREFERRED_FEED_IMAGE_FILENAMES = { "folder.jpg", "Folder.jpg", "folder.png", "Folder.png" };
 
@@ -197,6 +203,15 @@ public class LocalFeedUpdater {
         item.getMedia().setDuration((int) Long.parseLong(durationStr));
 
         item.getMedia().setHasEmbeddedPicture(mediaMetadataRetriever.getEmbeddedPicture() != null);
+
+        try (InputStream inputStream = context.getContentResolver().openInputStream(file.getUri())) {
+            Id3MetadataReader reader = new Id3MetadataReader(new CountingInputStream(inputStream));
+            reader.readInputStream();
+            item.setDescriptionIfLonger(reader.getComment());
+        } catch (IOException | ID3ReaderException e) {
+            // Do not flood Logcat with full stack traces
+            Log.d(TAG, "Unable to parse ID3 of " + file.getUri() + ": " + e.getMessage());
+        }
     }
 
     private static void reportError(Feed feed, String reasonDetailed) {

parser/media/src/main/java/de/danoeh/antennapod/parser/media/id3/Id3MetadataReader.java

@@ -0,0 +1,39 @@
+package de.danoeh.antennapod.parser.media.id3;
+
+import androidx.annotation.NonNull;
+import de.danoeh.antennapod.parser.media.id3.model.FrameHeader;
+import org.apache.commons.io.input.CountingInputStream;
+
+import java.io.IOException;
+
+/**
+ * Reads general ID3 metadata like comment, which Android's MediaMetadataReceiver does not support.
+ */
+public class Id3MetadataReader extends ID3Reader {
+    public static final String FRAME_ID_COMMENT = "COMM";
+
+    private String comment = null;
+
+    public Id3MetadataReader(CountingInputStream input) {
+        super(input);
+    }
+
+    @Override
+    protected void readFrame(@NonNull FrameHeader frameHeader) throws IOException, ID3ReaderException {
+        if (FRAME_ID_COMMENT.equals(frameHeader.getId())) {
+            long frameStart = getPosition();
+            int encoding = readByte();
+            skipBytes(3); // Language
+            String shortDescription = readEncodedString(encoding, frameHeader.getSize() - 4);
+            String longDescription = readEncodedString(encoding,
+                    (int) (frameHeader.getSize() - (getPosition() - frameStart)));
+            comment = shortDescription.length() > longDescription.length() ? shortDescription : longDescription;
+        } else {
+            super.readFrame(frameHeader);
+        }
+    }
+
+    public String getComment() {
+        return comment;
+    }
+}