There were extensive discussions (lasting two hours) of the proposed USAC Profiles and of the USAC Verification Test with the Convenor present. During the discussion on USAC Profiles the Requirements Chair was also present.
USAC Profiles
The Convenor explained that there is a long-standing tradition in MPEG that a profile is within an MPEG specification. He noted that the proposed profile HE-AAC V3 contains the MPEG-4 profile HE-AAC V2 and the proposed MPEG-D profile USAC Baseline, restricted to level 2. He noted that it is prevalent for manufacturers to support multiple profiles in a single produce, e.g. a DVD player supports MPEG-1 Video profiles, MPEG-2 Video profiles, MPEG-4 Video profiles (and MPEG-2 Audio profiles), and hence manufactures could realize the “HE-AAC V3” functionality by conforming to:
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HE-AAC V2 profile
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USAC Baseline profile Level 2
Hence, the Convenor emphasised that there is no need to deviate from the current scope that MPEG profiles have adhered to.
As an alternative, the Convenor noted that USAC could be moved to MPEG-4, in which case the “V3” profile would be within a single MPEG standard.
The Audio chair proposed that the two proposed USAC profiles be documented in an output document titled “Thoughts on USAC profiles” and that this topic be further studied and discussed with the goal of a resolution at the next MPEG meeting. The Chair noted that the “Study on USAC DIS” output document is silent on USAC profiles. The Chair further proposed that an Audio resolution ask National Bodies to study the “Study on” document when casting their ballot on the USAC DIS, and that this would make no reference to the “Thought on USAC profiles” document.
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