Summary

The major element in this amendment is the signalling of bandwidth extension data to MPEG-AAC audio ("AAC-plus"), which was implemented as follows:

1)          A new descriptor called "MPEG-2_AAC_audio_descriptor" has been added to signal AAC specific audio parameters in the PMT including the use of bandwidth extension data to MPEG-2 AAC.

2)          The MPEG-4_audio_profile_and_level table has been replaced by a newer table to include the bandwidth extension data to MPEG-4 audio.

3)          In the ISO_639_language_descriptor, the values for audio_type 0x04-0x7F have been changed from 'reserved' to 'user_private'. This change was done at the request of broadcasters to enable signalling ancillary audio as this could not be done earlier because all the values of audio_type (0x04-0xFF) were reserved.