| USAC Verification Test
The Chair presented
m21283
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Proposal for USAC Verification Test Report
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S.R. Quackenbush
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The contriution is a “skeleton” of the USAC Verification Test Report. The Chair encouraged experts to review the “test description” portion of the document. A break-out group progress the document and recommend to the Audio subgroup how to best present the results of the Verification Test. The edited document will be brought up for discussion later in the week.
USAC Common Encoder
Jeongook Song, Yonsei University, presented
m21239
|
Report on corrections to USAC Common Encoder Reference Software, JAME
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Jeongook Song, Hong-Goo Kang
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The contribution reports on the status of the USAC Common Encoder Reference Software. The following new modules were added to the encoder software:
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Psychoacoustic model
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Distortion control module depending on bit-demand
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Bit-reservoir module
The Chair suggested the following schedule for this work
AhG Period
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Work to be done
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97th to 98th meeting
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Additional development at Yonsei and ETRI. A small subjective test will at Yonsei and ETRI will report on the quality of the Common Encoder.
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98th to 99th meeting
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Additional development at Yonsei and ETRI. Draft workplan for a small subjective test to be conducted by Yonsei, ETRI and at least one additional company.
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99th to 100th meeting
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Additional development at Yonsei and ETRI. Draft workplan for formal verification test of MPEG Common Encoder Reference Software.
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Kristofer Kjorling, Dolby, presented
m21268
|
Proposed profiles for MPEG-D USAC
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Bernhard Grill, Max Neuendorf, Roch Lefebvre, Kristofer Kjorling, Heiko Purnhagen,Werner Oomen
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The contribution proposes two profiles for USAC.
The first is the USAC Baseline Profile. The definition of the profile is unchanged from what was proposed at the 96th MPEG meeting, which is that:
In the Baseline USAC profile the following coding tools shall not be employed:
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Time warped filterbank
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DFT based harmonic transposer in enhanced spectral band replication
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Fractional delay decorrelator in MPEG Surround for mono to stereo upmixing (MPS212)
Four different hierarchical levels are proposed with increasing number of audio channels and increasing complexity, as shown here:
Level
|
Max. channels
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Max. sampling rate [kHz]
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Max. PCU
|
Max. RCU
|
1
|
1
|
48
|
7
|
6
|
2
|
2
|
48
|
12
|
11
|
3
|
5.1
|
48
|
31
|
28
|
4
|
5.1
|
96
|
62
|
28
|
Level (Note 1)
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Max. channels/object
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Max. AAC sampling rate, SBR not present [kHz]
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Max. AAC sampling rate, SBR present [kHz]
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Max. SBR sampling rate [kHz] (in/out)
|
Max. PCU
|
Max. RCU
|
Max. PCU HQ / LP SBR
(Note 5)
|
Max. RCU HQ / LP SBR
(Note 5)
|
1
|
NA
|
NA
|
NA
|
NA
|
NA
|
NA
|
NA
|
NA
|
2
|
2
|
48
|
24
|
24/48
|
12
|
11
|
12
|
11
|
3
|
2
|
48
|
24/48 (Note 3)
|
48/48 (Note 2)
|
15
|
11
|
15
|
11
|
4
|
5
|
48
|
24/48 (Note 4)
|
48/48 (Note 2)
|
25
|
28
|
20
|
23
|
5
|
5
|
96
|
48
|
48/96
|
49
|
28
|
39
|
23
|
Note 1: Level 2, 3, and 4 Extended HE AAC profile decoders implement the baseline version of the parametric stereo tool. A level 5 decoder shall not be limited to the baseline version of the parametric stereo tool.
Note 2: For level 3 and level 4 decoders, it is mandatory to operate the SBR tool in downsampled mode if the sampling rate of the AAC core is higher than 24kHz. Hence, if the SBR tool operates on a 48kHz signal, the internal sampling rate of the SBR tool will be 96kHz, however, the output signal will be downsampled by the SBR tool to 48kHz.
Note 3: If Parametric Stereo data is present the maximum AAC sampling rate is 24kHz, if Parametric Stereo data is not present the maximum AAC sampling rate is 48kHz.
Note 4: For one or two channels the maximum AAC sampling rate, with SBR present, is 48kHz. For more than two channels the maximum AAC sampling rate, with SBR present, is 24kHz.
Note 5: The PCU/RCU number are given for a decoder operating the LP SBR tool whenever applicable.
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The second is the Extended High Efficiency AAC Profile. The Extended HE-AAC profile contains the audio object types 42 (USAC), 5 (SBR), 29 (PS) and 2 (AAC LC) as defined in ISO/IEC 14496-3. In addition, it includes Level 2 of the Baseline USAC profile.
This profile has the support from the following companies:
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Dolby Laboratories, Fraunhofer IIS, Philips, VoiceAge Corp., Panasonic, Apple, Sony
As a result, a decoder that conforms to the Extended High Efficiency AAC Profile can play bitstreams that conform to any of the following profiles:
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AAC Profile
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HE-AAC Profile
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HE-AAC V2 Profile
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Baseline USAC Profile
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