Flip input buffer even if the end of stream is reached.

Sometimes the empty end of stream buffer has a non-zero
data limit. Calling flip first, resets the limit to the
position which is zero in these cases.

PiperOrigin-RevId: 413156455

library/transformer/src/main/java/com/google/android/exoplayer2/transformer/TransformerBaseRenderer.java

@@ -197,13 +197,13 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
     int result = readSource(getFormatHolder(), samplePipelineInputBuffer, /* readFlags= */ 0);
     switch (result) {
       case C.RESULT_BUFFER_READ:
+        samplePipelineInputBuffer.flip();
         if (samplePipelineInputBuffer.isEndOfStream()) {
           samplePipeline.queueInputBuffer();
           return false;
         }
         mediaClock.updateTimeForTrackType(getTrackType(), samplePipelineInputBuffer.timeUs);
         samplePipelineInputBuffer.timeUs -= streamOffsetUs;
-        samplePipelineInputBuffer.flip();
         checkStateNotNull(samplePipelineInputBuffer.data);
         maybeQueueSampleToPipeline(samplePipelineInputBuffer);
         return true;

testdata/src/test/assets/transformerdumps/mp4/sample_sef_slow_motion.mp4.dump

@@ -299,12 +299,6 @@ sample:
   isKeyFrame = false
   presentationTimeUs = 734083
 sample:
-  trackIndex = 0
-  dataHashCode = 820561200
-  size = 1252
-  isKeyFrame = true
-  presentationTimeUs = 201521
-sample:
   trackIndex = 1
   dataHashCode = -1554795381
   size = 205