Don't use WavHeader.averageBytesPerSecond

It's unreliable for at least one IMA ADPCM file I've found.
Calculating the blockIndex to seek to using exact properties
also seems more robust.

Note this doesn't change anything for the existing PCM test,
since averageBytesPerSecond is set correctly. It does make
a difference for an upcoming IMA ADPCM test though.

PiperOrigin-RevId: 287814947

library/core/src/main/java/com/google/android/exoplayer2/extractor/wav/WavExtractor.java

@@ -203,7 +203,7 @@ public final class WavExtractor implements Extractor {
               /* id= */ null,
               MimeTypes.AUDIO_RAW,
               /* codecs= */ null,
-              /* bitrate= */ header.averageBytesPerSecond * 8,
+              /* bitrate= */ header.frameRateHz * bytesPerFrame * 8,
               targetSampleSize,
               header.numChannels,
               header.frameRateHz,

library/core/src/main/java/com/google/android/exoplayer2/extractor/wav/WavSeekMap.java

@@ -49,20 +49,18 @@ import com.google.android.exoplayer2.util.Util;
 
   @Override
   public SeekPoints getSeekPoints(long timeUs) {
-    // Calculate the expected number of bytes of sample data corresponding to the requested time.
-    long positionOffset = (timeUs * wavHeader.averageBytesPerSecond) / C.MICROS_PER_SECOND;
     // Calculate the containing block index, constraining to valid indices.
-    long blockSize = wavHeader.blockSize;
-    long blockIndex = Util.constrainValue(positionOffset / blockSize, 0, blockCount - 1);
+    long blockIndex = (timeUs * wavHeader.frameRateHz) / (C.MICROS_PER_SECOND * framesPerBlock);
+    blockIndex = Util.constrainValue(blockIndex, 0, blockCount - 1);
 
-    long seekPosition = firstBlockPosition + (blockIndex * blockSize);
+    long seekPosition = firstBlockPosition + (blockIndex * wavHeader.blockSize);
     long seekTimeUs = blockIndexToTimeUs(blockIndex);
     SeekPoint seekPoint = new SeekPoint(seekTimeUs, seekPosition);
     if (seekTimeUs >= timeUs || blockIndex == blockCount - 1) {
       return new SeekPoints(seekPoint);
     } else {
       long secondBlockIndex = blockIndex + 1;
-      long secondSeekPosition = firstBlockPosition + (secondBlockIndex * blockSize);
+      long secondSeekPosition = firstBlockPosition + (secondBlockIndex * wavHeader.blockSize);
       long secondSeekTimeUs = blockIndexToTimeUs(secondBlockIndex);
       SeekPoint secondSeekPoint = new SeekPoint(secondSeekTimeUs, secondSeekPosition);
       return new SeekPoints(seekPoint, secondSeekPoint);