MP3 extractor: refactor seeker initialization

PiperOrigin-RevId: 291405419

library/extractor/src/main/java/com/google/android/exoplayer2/extractor/mp3/Mp3Extractor.java

@@ -190,24 +190,7 @@ public final class Mp3Extractor implements Extractor {
       }
       }
     }
     }
     if (seeker == null) {
     if (seeker == null) {
-      // Read past any seek frame and set the seeker based on metadata or a seek frame. Metadata
-      // takes priority as it can provide greater precision.
-      Seeker seekFrameSeeker = maybeReadSeekFrame(input);
-      Seeker metadataSeeker = maybeHandleSeekMetadata(metadata, input.getPosition());
-
-      if (disableSeeking) {
-        seeker = new UnseekableSeeker();
-      } else {
-        if (metadataSeeker != null) {
-          seeker = metadataSeeker;
-        } else if (seekFrameSeeker != null) {
-          seeker = seekFrameSeeker;
-        }
-        if (seeker == null
-            || (!seeker.isSeekable() && (flags & FLAG_ENABLE_CONSTANT_BITRATE_SEEKING) != 0)) {
-          seeker = getConstantBitrateSeeker(input);
-        }
-      }
+      seeker = computeSeeker(input);
       extractorOutput.seekMap(seeker);
       extractorOutput.seekMap(seeker);
       trackOutput.format(
       trackOutput.format(
           Format.createAudioSampleFormat(
           Format.createAudioSampleFormat(
@@ -385,6 +368,31 @@ public final class Mp3Extractor implements Extractor {
     }
     }
   }
   }
 
 
+  private Seeker computeSeeker(ExtractorInput input) throws IOException, InterruptedException {
+    // Read past any seek frame and set the seeker based on metadata or a seek frame. Metadata
+    // takes priority as it can provide greater precision.
+    Seeker seekFrameSeeker = maybeReadSeekFrame(input);
+    Seeker metadataSeeker = maybeHandleSeekMetadata(metadata, input.getPosition());
+
+    if (disableSeeking) {
+      return new UnseekableSeeker();
+    }
+
+    @Nullable Seeker resultSeeker = null;
+    if (metadataSeeker != null) {
+      resultSeeker = metadataSeeker;
+    } else if (seekFrameSeeker != null) {
+      resultSeeker = seekFrameSeeker;
+    }
+
+    if (resultSeeker == null
+        || (!resultSeeker.isSeekable() && (flags & FLAG_ENABLE_CONSTANT_BITRATE_SEEKING) != 0)) {
+      resultSeeker = getConstantBitrateSeeker(input);
+    }
+
+    return resultSeeker;
+  }
+
   /**
   /**
    * Consumes the next frame from the {@code input} if it contains VBRI or Xing seeking metadata,
    * Consumes the next frame from the {@code input} if it contains VBRI or Xing seeking metadata,
    * returning a {@link Seeker} if the metadata was present and valid, or {@code null} otherwise.
    * returning a {@link Seeker} if the metadata was present and valid, or {@code null} otherwise.