MPEG-4 BSAC Technology

Transcription

1 MPEG-4 BSAC Technology 6DPVXQJ$,7

2 Introduction to BSAC What is BSAC Bit Sliced Arithmetic Coding alternative noiseless coding tool for MPEG-4 AAC to provide fine grain scalability functionality Characteristics of BSAC High coding efficiency: transcoding of AAC Small step scalability with 1kbps/ch (scalable range : 16kbps/ch ~ 64kbps/ch) Error resilient capability (SBA mode)

3 Comparison with AAC BSAC method top down scalability BSAC AAC- LC Huffman decoding Arithmetic decoding small step scalability with 1kbps/ch Inverse Quantizer enhancement layer single decoding pass Bitstream Demux M/S stereo Processing Intensity Processing TNS Filter Bank

4 Basic idea of BSAC Bit sliced approach: Slice those quantized data in bit order Spectral d ata x[i] x[i+1] x[i+2] x[i+3] MSB LSB Conventional pro cessing unit : (Least Significant Vector) : (4th Significant Vector) : (3rd Significant Vector) : (2nd Significant Vector) : (Most Significant Vector)

5 Concept of BSAC bitstream Top Layer : Layer 1 + Layer Layer N z z z Intermediate layer : Layer 1 + Layer 2 (1st Enhancement Layer) Base layer : Layer 1 header zzz Side info. for Base Layer Side info. for Layer 2 Side info. for Top Layer data for Base Layer (MSVs) data for 1st Enhancement Layer (2nd MSVs) data for Nth Enhancement Layer (LSVs)

6 SBA mode Segmented Binary Arithmetic Coding provides error resiliency partitions the arithmetic codeword into some sections provides very little overhead (less than 1 %) Decoding concept of SBA mode Segment 0 Segment 1 Segment 2 Segment n Layer 0 Layer 1 Layer 2 Layer 3 Layer 4 Layer 5 Layer N Layer 0 0 stuffing Layer 4 Layer stuffing Layer 1 Layer 2 Layer3 0 stuffing... Layer N 0 stuffing

7 Performances of BSAC All items BSAC64 BSAC72 BSAC80 BSAC88 BSAC96 AAC64 AAC96 Source : ISO/IEC JTC1/SC29/WG11/w3075 (Report on the MPEG-4 Version 2 Verification Test)

8 100Mbps LAN Streaming service with BSAC Active Router 128kbps ISDN Network B 64kbps user 1 user 2 Network A 56kbps MOD Server 1Mbps ADSL reduces a burden of the Server - have only one bitstream

9 100Mbps LAN Streaming service with BSAC Active Router 128kbps ISDN Network B 64kbps user 1 user 2 Network A 56kbps MOD Server 1Mbps ADSL Network C 96kbps user 3 80kbps user 4 reduces a burden of the Router - do not need a transcoding

10 100Mbps LAN Streaming service with BSAC Active Router 128kbps ISDN Network B 64kbps user 1 user 2 Network A 56kbps MOD Server 1Mbps ADSL Network C 96kbps user 3 reduces a burden of the Server - have only one bitstream reduces a burden of the Router - do not need a transcoding 80kbps user 4

11 QoS with BSAC Menu order Food If you pay 10 If you pay 20 If you pay 30 If you pay 40

12 QoS with BSAC Menu order Food If you pay 10 If you pay addit ional 10 If you pay addit ional 10 If you pay addit ional 10

13 QoS with BSAC http serverhttp server http server http server server LAN 100 MHz 1024kb/s client 1 64kb/s Proximity Router client 2 ISDN 2048kb/s 64kb/s client 3 64kb/s GSTN client 4 64kb/s client 5 128kb/s 128kb/s client 6 128kb/s client 7 128kb/s 128kb/s 128kb/s client 8 client 9 client10

14 QoS with BSAC http serverhttp server http server http server server LAN 100 MHz 1024kb/s client 1 64kb/s Proximity Router client 2 ISDN 2048kb/s 64kb/s client 3 64kb/s GSTN client 4 64kb/s client 5 128kb/s 128kb/s client 6 128kb/s client 7 128kb/s 128kb/s 128kb/s 128kb/s client 8 client 9 client10 client11

15 QoS with BSAC http serverhttp server http server http server server LAN 100 MHz 1024kb/s client 1 56kb/s Proximity Router client 2 ISDN 2048kb/s 56kb/s client 3 56kb/s GSTN client 4 56kb/s client 5 112kb/s 112kb/s client 6 112kb/s client 7 112kb/s 112kb/s 112kb/s 112kb/s client 8 client 9 client10 client11

16 Conclusions Alternative noiseless coding tool of MPEG-4 AAC Fine grain scalability with 1kbps/ch with graceful quality degradation with top down scalability High coding efficiency at top bitrate Error resilient capability

17 Demonstration-1 Item : 48kHz, mono, 64kbps ~ 40kbps Bitrate (kbps) Time(sec.)

18 Demonstration-2 Item : 32kHz, stereo, 96kbps ~ 64kbps Bitrate (kbps) Time(sec.)