am 35de4831: am d1e8f467: am 99a86d06: Clarify that MediaFormat.KEY_IS_ADTS only applies to decoding AAC audio content

* commit '35de48317f51a1331e2c6f279c5a2e76b65469ad':
  Clarify that MediaFormat.KEY_IS_ADTS only applies to decoding AAC audio content