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HUAWEI TECHNOLOGIES CO., LTD.

MPEG USAC

Minjie Xie

Huawei Technologies


www.huawei.com


• MPEG-1: standardized in 1992

• MPEG-2: standardized in 1994-1997

• MPEG-4: standardized in 1998-2004

• MPEG Surround: standardized in 2006

• MPEG Unified Speech and Audio Coding

(USAC): ongoing

Overview of Main MPEG Audio Standards


• Layer I: provides broadcast quality at 192 kbps

per channel

• Layer II: provides broadcast quality at 128 kbps

per channel

• Layer III (MP3): provides broadcast quality at 96

kbps per channel

MPEG-1 Audio Standard


• MPEG-2: low sampling rate (16 kHz, 22.05 kHz,

and 24 kHz) and multichannel

• MPEG-2 Advanced Audio Coding (AAC):

provides broadcast quality at 64 kbps per

channel

- Sampling rate : 8 – 96 kHz

- Bit rate: 16 – 128 kbps



• MPEG-4 Low-Delay AAC (AAC-LD): 10-ms

frame length at a sampling rate of 48 kHz

• MPEG-4 High-Efficiency AAC (HE-AAC):

combination of an AAC coder with bandwidth

extension



• Spatial parameter coding: side information for

multichannel

• Core coder: stereo downmix from Surround

• 48 kbps for 5.1 channel (9.6 kbps per channel)

MPEG Surround


• Call for Proposals was issued at the 82nd MPEG

meeting in October, 2007

• USAC Reference Model 0 (RM0) was selected

at the 85th MPEG meeting in July, 2008

• Development of a USAC MPEG Reference

Encoder was proposed and agreed at the 86th

MPEG meeting in October, 2008

MPEG USAC


• Multimedia download to mobile devices

• Mobile TV

• Digital Radio

• Audio books

Envisioned Use Cases


• Bit rate: 12 – 64 kbps

• Channel: mono and stereo

• Signal: speech, music, and mixed content

• Quality: better than 3GPP AMR-WB+ or eAAC+

(HE-AAC v2)

• Delay: not specified

• Complexity: not specified

Requirements for USAC


• More than 20 CEs contributions on Reference

Model were submitted

• Four missing modules for USAC MPEG

Reference Encoder were contributed:

3 contributions from Huawei and 1 contribution

from Qualcomm

Core Experiments (CEs) on USAC


MPEG USAC Encoder (RM0)

MPEGSurround eSBR

ACELP/TCX(LPD)

Bitstream Multiplexer

Signal Classifier

Inputaudio

AAC Tools(FD)

Quantizationand Coding

Codeddata


• Signal classification

- Indicate signal category – speech or music

• MPEG Surround

- Create downmix mono from the stereo signal

as input to Core Coder

- Extract spatial parameters as side information

• SBR

- Bandwidth extension for high frequencies

Common Pre-processing


• Selected to code music at lower bit rates and

both speech and music at higher bit rates

• AAC tools

- TW-MDCT, Block switching, Perceptual model,

Temporal Noise Shaping (TNS), Bit-reservoir,

M/S, Quantization and coding, etc.

Frequency-Domain Encoding (AAC)


• Selected to code speech signal for lower bit

rates

• ACELP

- Algebraic codebook, AVQ-based LPC

• TCX

- MDCT-based transform coding, transform

coefficients quantized and coded with AAC tools

as in FD Mode

LP-Domain Encoding (ACELP/TCX)


MPEG USAC Decoder (RM0)

Bitstream De-multiplexer

Codeddata

De-quantizationand Decoding

ACELP/TCX(LPD)

AAC Tools(FD)

MPEGSurroundeSBR

Outputaudio


• Decoding the quantized and coded spectra (FD),

OR LP parameters with the quantized and coded

spectra (TCX) or coded TD excitation (ACELP)

• Filterbank control information

• eSBR control information

• MPEG Surround control information

• Other control information

Decoding of MPEG USAC


• Provide best audio quality for all signal types

• Be used for audio storage and streaming

• Continue the CE process

• Continue the development of the USAC MPEG

Reference Encoder

• Be finalized in 2011 (???)

Summary


Thank You

www.huawei.com

minjie xie - xidian.edu.cnsee.xidian.edu.cn/conference/mpegjpeg/workshop/ppt/xieminjie.pdf ·...

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