Throw a ParserException instead of a NullPointerException if the sample table (stbl) is missing a required sample description (stsd).

As per the javadoc for AtomParsers.parseTrack, ParserException should be "thrown if the trak atom can't be parsed."

PiperOrigin-RevId: 499522748

RELEASENOTES.md

@@ -20,6 +20,9 @@ Release notes
         for seeking.
     *   Use theme when loading drawables on API 21+
         ([#220](https://github.com/androidx/media/issues/220)).
+    *   Throw a ParserException instead of a NullPointerException if the sample
+    *   table (stbl) is missing a required sample description (stsd) when
+    *   parsing trak atoms.
 *   Audio:
     *   Use the compressed audio format bitrate to calculate the min buffer size
         for `AudioTrack` in direct playbacks (passthrough).

libraries/extractor/src/main/java/androidx/media3/extractor/mp4/AtomParsers.java

@@ -43,6 +43,7 @@ import androidx.media3.extractor.GaplessInfoHolder;
 import androidx.media3.extractor.HevcConfig;
 import androidx.media3.extractor.OpusUtil;
 import androidx.media3.extractor.metadata.mp4.SmtaMetadataEntry;
+import androidx.media3.extractor.mp4.Atom.LeafAtom;
 import com.google.common.base.Function;
 import com.google.common.collect.ImmutableList;
 import com.google.common.primitives.Ints;
@@ -308,9 +309,14 @@ import org.checkerframework.checker.nullness.compatqual.NullableType;
 
     Pair<Long, String> mdhdData =
         parseMdhd(checkNotNull(mdia.getLeafAtomOfType(Atom.TYPE_mdhd)).data);
+    LeafAtom stsd = stbl.getLeafAtomOfType(Atom.TYPE_stsd);
+    if (stsd == null) {
+      throw ParserException.createForMalformedContainer(
+          "Malformed sample table (stbl) missing sample description (stsd)", /* cause= */ null);
+    }
     StsdData stsdData =
         parseStsd(
-            checkNotNull(stbl.getLeafAtomOfType(Atom.TYPE_stsd)).data,
+            stsd.data,
             tkhdData.id,
             tkhdData.rotationDegrees,
             mdhdData.second,