MPEG Spatial Audio Coding Multichannel Audio for Broadcasting

Transcription

1 MPEG Spatial Coding Multichannel for Broadcasting Olaf Korte Fraunhofer IIS Broadcast Applications & Multimedia ealtime Systems phone: +49-(0) 9131 / fax: +49-(0) 9131 /

2 Overview MPEG Spatial Motivation and Broadcast equirements Spatial Coding MPEG Standardization Process Current Status (MPEG M0) adio and todays Demo setup Conclusion and Outlook 2

3 Motivation MPEG Spatial Killer Application for Digital adio Competitive Media support Surround Sound Broadcasters start with Surround Sound (DVB-S, XM, Sirius) Car Industry supports Surround Sound 3

4 Broadcast equirements MPEG Spatial 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 ow Extra Costs for Transmission 4

5 Spatial Coding MPEG Spatial artistic downmix (optional) Stereo or mono SAC Encoder SAC Decoder Multi- Channel N channels ch1 ch2 chn Automatic downmix (optional) Spatial Parameters Estimation Stereo or mono Spatial parameters Spatial Multi-channel reconstruction ch1 ch2 chn 5

6 Spatial Coding MPEG Spatial Works on mono or stereo core and leave this untouched Spatial parameters contain most salient perceptual aspects of multi channelsound 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 systems have capabilities to transport side information transparently (MPEG layer 2, mp3, HE AAC: Ancilliary data) 6

7 MPEG Spatial Spatial Coding - Bitrate/Quality Scalability Multi Channel Quality Transparency Spatial Coding Matrixed Surround SpatialParameter Bitrate 7

8 Spatial Coding MPEG Spatial adio Spatial (96/16kbps) Complete ealtime Broadcast Chain (FhG/Omnia/Telos, 2004/2005) adio Parametric Surround adio Codec Demo (CT, 2004) Eureka 147 DAB 5.1 (192/16kbps) Broadcasts forwhole bavaria (B/FhG, 2004) Eureka 147 DAB Parametric Surround (256/32kbps) (IT/CT, 2004) HE AAC mp3surround (16kbps) (2004) HE AAC Spatial Surround (48/16kbps) (FhG, 2004) 8

9 MPEG Standardisation MPEG Spatial Spring 2004: 4 concurrent systems are proposed to MPEG Oct 2004: MPEG istening Test esults showed that the two best systems performed equally ( CT/Philips and FhG/Agere-Systems ) Oct 2004: MPEG decided to develop a merged system M0: First version of merged system M0 test results available since April 2005 Committee Draft in July

10 MPEG Spatial Current Status elease Milestone 0 ( M0 ) MPEG M0 test cases (MUSHA) 7 independent test sites with a total of 279 listening subjects) Bitrate (kbps) Test Condition t1a (525, 160kbps) Test Condition t2a (515, 80kbps) Test Condition t3 (515, 48kbps) M M0 low_rate M0 high_quality

11 MPEG Spatial Current Status elease Milestone 0 ( M0 ) Spatial bitrate (kbps) 60 MOS CTP_CfP FhG-A _CfP 40 M0 D P t1a (525) t2a (515) Test case t3 (48kbps) t1rhq (525) 11

12 MPEG Spatial adio with MPEG Spatial Coding Station Encoder Multiplexer Stereo eceiver De-Mux Decoder 12

13 MPEG Spatial adio with MPEG Spatial Coding Enhanced Surround eceiver Station with artistic downmix De-Mux Decoder MPEG Spatial MPEG Spatial Decoder F F C FE S S F F C FE S S MPEG Spatial Encoder Encoder MPEG Spatial Multiplexer Stereo eceiver De-Mux Decoder 13

14 MPEG Spatial adio with MPEG Spatial Coding Enhanced Surround eceiver Station with automatic downmix De-Mux Decoder MPEG Spatial MPEG Spatial Decoder F F C FE S S F F C FE S S Downmix and MPEG Spatial Encoder Encoder MPEG Spatial Multiplexer Stereo eceiver De-Mux Decoder 14

15 MPEG Spatial MPEG Spatial M0 demo for adio MPEG Spatial M0 Current Implementation Status Encoder Mathlab Code available for generation of test items ealtime Implementation under development Decoder Mathlab Code available ealtime Implementation for PC code available 15

16 MPEG Spatial MPEG Spatial M0 demo for adio Non-ealtime Encoding (prepared for the demo) *.wav discrete 5.1 Files 5.1 Downmix and MPEG Spatial Encoder Stereo downmix wave files MPEG Spatial Parameters 5,85kbps *.bs Spatial Data 16

17 MPEG Spatial MPEG Spatial M0 demo for adio Non-ealtime Encoding (prepared for the demo) Stereo downmix wave files Encoder C 90kbps Decoder Encoding and Decoding done by Coding Technologies Stereo *_hdc.wav stereo quality wave files 17

18 MPEG Spatial MPEG Spatial M0 demo for adio Non-ealtime Encoding (prepared for the demo) *.wave discrete 5.1 Files 5.1 Downmix and MPEG Spatial Encoder Stereo downmix wave files Encoder MPEG Spatial Parameters 5,85kbps C 90kbps Decoder Encoding and Decoding done by Coding Technologies Stereo *._hdc.wav stereo quality wave files *.bs Spatial Data 18

19 MPEG Spatial MPEG Spatial M0 demo for adio ealtime Decoding at the demo F F *_hdc.wav stereo quality wave files MPEG Spatial Decoder 5.1 External 6ch USB Soundcard C FE S S MPEG Spatial Parameters 5,85kbps *.bs Spatial Data 19

20 MPEG Spatial MPEG Spatial M0 demo for adio ealtime Decoding at the demo F F *_hdc.wav stereo quality wave files MPEG Spatial Decoder 5.1 External 6ch USB Soundcard C FE S S MPEG Spatial Parameters 5,85kbps *.bs Spatial Data *_dec.wav Decoded 5.1 wave files 20

21 MPEG Spatial MPEG Spatial M0 demo for adio ealtime Comparison Original / M0 5.1 / stereo *.wav discrete 5.1 wave files Original 5.1 F F *_dec.wav M0 5.1 wave files Spatial5.1 WavSwitch External 6ch USB Soundcard C FE S S Downmix *_hdc.wav stereo quality wave files 21

22 Conclusion MPEG Spatial MPEG Spatial offers perfect multichannel for adio Highly Scalable (matrix, high quality, transparent) Backwardscompatible (perfect downmix) Future looking Technology (e.g. 7.1, 10.2, ) Open MPEG standard Is a must for adio! (for sure will also be used in many other applications) 22

23 Outlook MPEG Spatial MPEG M0 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 adio! We strongly recommend an independent MUSHA testing by a neutral party for direct comparison of proposed systems Cost of this testing shall be be divided among the proponents 23