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Olaf Korte
Fraunhofer IISBroadcast ApplicationsAudio & Multimedia Realtime Systems
[email protected]: +49-(0) 9131 / 776-6330fax: +49-(0) 9131 / 776-398
Fraunhofer Institut Integrierte Schaltungen
MPEG Spatial Audio CodingMultichannel Audio for Broadcasting
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
2Olaf Korte © by Fraunhofer IIS, 9st May 2005
Overview
– Motivation and Broadcast Requirements
– Spatial Audio Coding
– MPEG Standardization Process
– Current Status (MPEG RM0)
– HD Radio and todays Demo setup
– Conclusion and Outlook
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
3Olaf Korte © by Fraunhofer IIS, 9st May 2005
Motivation
– Killer Application for Digital Radio
– Competitive Media support Surround Sound
– Broadcasters start with Surround Sound
(DVB-S, XM, Sirius)
– Car Industry supports Surround Sound
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
4Olaf Korte © by Fraunhofer IIS, 9st May 2005
Broadcast Requirements– Backwards Compatibility
– No simulcast
– No quality loss for conventional receivers
– High Quality
– Stereo (artistic downmix)
– Multichannel (as discrete as possible)
– For all kind of material
– Low Extra Costs for Transmission
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
5Olaf Korte © by Fraunhofer IIS, 9st May 2005
Spatial Audio Coding
Spatialparameters
SpatialMulti-channelreconstruction
ch1ch2
chN
SAC Decoder
Stereoor
monoch1ch2
chN
Stereoormono
Multi-Channel
N channels
Automaticdownmix(optional)
SpatialParametersEstimation
artisticdownmix(optional)
SAC Encoder
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
6Olaf Korte © by Fraunhofer IIS, 9st May 2005
Spatial Audio Coding– Works on mono or stereo core and leave this untouched
– Spatial parameters contain most salient perceptual aspects of multi channel sound image, e.g.
– Interchannel level differences
– Interchannel time/Phase differences
– Interchannel correlation/coherence
– Scalable with regard to freq. bands, time resolution, …
– Scalable bitrate (quality) for Spatial parameters
– Most Digital Audio systems have capabilities to transport sideinformation transparently(MPEG layer 2, mp3, HE AAC: Ancilliary data)
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
7Olaf Korte © by Fraunhofer IIS, 9st May 2005
Spatial Audio Coding - Bitrate/Quality Scalability
Multi ChannelQuality
Spatial Parameter Bitrate
Transparency
Matrixed Surround
Spatial Audio Coding
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
8Olaf Korte © by Fraunhofer IIS, 9st May 2005
Spatial Audio Coding– “HD Radio Spatial Audio“ (96/16kbps)
Complete Realtime Broadcast Chain(FhG/Omnia/Telos, 2004/2005)
– “HD Radio Parametric Surround“HD Radio Codec Demo (CT, 2004)
– Eureka 147 “DAB 5.1“ (192/16kbps)Broadcasts for whole bavaria (BR/FhG, 2004)
– Eureka 147 DAB Parametric Surround (256/32kbps)(IRT/CT, 2004)
– “mp3surround“ (16kbps) (2004)
– HE AAC Spatial Surround (48/16kbps) (FhG, 2004)HE AAC
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
9Olaf Korte © by Fraunhofer IIS, 9st May 2005
MPEG Standardisation
– Spring 2004: 4 concurrent systems are proposed to MPEG
– Oct 2004: MPEG Listening Test Results showed that the two
best systems performed equally
(“CT/Philips“ and “FhG/Agere-Systems“)
– Oct 2004: MPEG decided to develop a merged system
– RM0: First version of merged system
– RM0 test results available since April 2005
– Committee Draft in July 2005
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
10Olaf Korte © by Fraunhofer IIS, 9st May 2005
Current Status – Release Milestone 0 („RM0“)
--31.65RM0 high_quality
--5.85RM0 low_rate
4.6811.7811.68RM0
Test Condition t3
(515, 48kbps)
Test Condition t2a
(515, 80kbps)
Test Condition t1a
(525, 160kbps)
Bitrate (kbps)
MPEG RM0 test cases (MUSHRA)
7 independent test sites with a total of 279 listening subjects)
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
11Olaf Korte © by Fraunhofer IIS, 9st May 2005
Current Status – Release Milestone 0 („RM0“)
0
20
40
60
80
100
t1a(525)
t2a(515)
t3(48kbps)
t1LrHq(525)
CTP_CfP
FhG-A _CfP
R M0
D PL2
22 17 12 23 16 12 13 9 5 6 12 32
MO
S
Test case
Spatial bitra te(kbps)
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
12Olaf Korte © by Fraunhofer IIS, 9st May 2005
HD Radio with MPEG Spatial Audio Coding
HDAudio
Decoder
HDBitstreamDe-Mux
L
R
HD Stereo Receiver
HDAudio
Encoder HDBitstream
Multiplexer
L
R
L
R
HD Station
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
13Olaf Korte © by Fraunhofer IIS, 9st May 2005
HD Radio with MPEG Spatial Audio Coding
Enhanced HD Surround Receiver
HDAudio
Decoder
HDBitstreamDe-Mux
L
R
HD Stereo Receiver
HDAudio
Decoder
MPEGSpatialAudio
Decoder
HDBitstreamDe-Mux
L
R
LFRFC
LFELS
RSMPEG Spatial
Bitstream
HDAudio
Encoder
MPEGSpatial
Encoder
HDBitstream
Multiplexer
L
R
MPEG SpatialBitstream
L
R
HD Station with artistic downmix
LFRFC
LFELS
RS
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
14Olaf Korte © by Fraunhofer IIS, 9st May 2005
HD Radio with MPEG Spatial Audio Coding
Enhanced HD Surround Receiver
HDAudio
Decoder
HDBitstreamDe-Mux
L
R
HD Stereo Receiver
HDAudio
Decoder
MPEGSpatialAudio
Decoder
HDBitstreamDe-Mux
L
R
MPEG SpatialBitstream
HDAudio
Encoder
Downmixand
MPEGSpatial
Encoder
HDBitstream
MultiplexerLFRFC
LFELS
RS
L
R
MPEG SpatialBitstream
HD Station with automatic downmix
LFRFC
LFELS
RS
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
15Olaf Korte © by Fraunhofer IIS, 9st May 2005
MPEG Spatial Audio RM0 demo for HD Radio
MPEG Spatial Audio RM0Current Implementation Status
– Encoder
– Mathlab Code available for generation of test items
– Realtime Implementation under development
– Decoder
– Mathlab Code available
– Realtime Implementation for PC code available
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
16Olaf Korte © by Fraunhofer IIS, 9st May 2005
MPEG Spatial Audio RM0 demo for HD Radio
Non-Realtime Encoding (prepared for the demo)
Downmixand
MPEGSpatial
Encoder*.wav
discrete5.1 Files
*.bsSpatial Data
Bitstream
Stereodownmixwave files
5.1
MPEG Spatial Audio Parameters Bitstream5,85kbps
L
R
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
17Olaf Korte © by Fraunhofer IIS, 9st May 2005
MPEG Spatial Audio RM0 demo for HD Radio
Non-Realtime Encoding (prepared for the demo)
Stereodownmixwave files
HDAudio
Encoder
HDAudio
Decoder*_hdc.wav
HD stereo qualitywave files
L
R
HDC AudioBitstream
90kbpsStereo
Encoding and Decoding done byCoding Technologies
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
18Olaf Korte © by Fraunhofer IIS, 9st May 2005
MPEG Spatial Audio RM0 demo for HD Radio
Non-Realtime Encoding (prepared for the demo)
Downmixand
MPEGSpatial
Encoder*.wavediscrete5.1 Files
*.bsSpatial Data
Bitstream
Stereodownmixwave files
HDAudio
Encoder
HDAudio
Decoder*._hdc.wav
HD stereo qualitywave files
5.1
MPEG Spatial Audio Parameters Bitstream5,85kbps
L
R
L
R
HDC AudioBitstream
90kbpsStereo
Encoding and Decoding done byCoding Technologies
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
19Olaf Korte © by Fraunhofer IIS, 9st May 2005
MPEGSpatial
Decoder
MPEG Spatial Audio RM0 demo for HD Radio
*.bsSpatial Data
Bitstream
*_hdc.wavHD stereo quality
wave files
MPEG Spatial AudioParameters Bitstream
5,85kbps
L
R
Realtime Decoding at the demo
External6chUSB
Soundcard
5.1Audio
LF
RF
C
LFE
LS
RS
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
20Olaf Korte © by Fraunhofer IIS, 9st May 2005
MPEGSpatial
Decoder
MPEG Spatial Audio RM0 demo for HD Radio
*.bsSpatial Data
Bitstream
*_hdc.wavHD stereo quality
wave files
MPEG Spatial AudioParameters Bitstream
5,85kbps
L
R
Realtime Decoding at the demo
External6chUSB
Soundcard
5.1Audio
*_dec.wavDecoded 5.1
wave files
LF
RF
C
LFE
LS
RS
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
21Olaf Korte © by Fraunhofer IIS, 9st May 2005
WavSwitch
MPEG Spatial Audio RM0 demo for HD Radio
Realtime ComparisonOriginal / RM0 5.1 / HD stereo
External6chUSB
Soundcard
LF
RF
C
LFE
LS
RS
*_dec.wavRM0 5.1
wave files
*_hdc.wavHD stereo quality
wave files
*.wavdiscrete 5.1wave files
Original 5.1
Spatial 5.1
Downmix
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
22Olaf Korte © by Fraunhofer IIS, 9st May 2005
Conclusion
– MPEG Spatial Audio offers perfect multichannel for HD Radio
– Highly Scalable (matrix, high quality, transparent)
– Backwards compatible (perfect downmix)
– Future looking Technology (e.g. 7.1, 10.2, …)
– Open MPEG standard
– Is a must for HD Radio!
(for sure will also be used in many other applications)
MPEG Spatial Audio –Multichannel Audio for HD Radio
Fraunhofer Institut Integrierte Schaltungen
23Olaf Korte © by Fraunhofer IIS, 9st May 2005
Outlook
– MPEG RM0 offers high quality and flexiblity
though it is only the basic profile of the new standard!
– A Digital Solution for a Digital System:
Choose the best available system for HD Radio!
– We strongly recommend an independent MUSHRA testing by a
neutral party for direct comparison of proposed systems
– Cost of this testing shall be be divided among the proponents