1. MPEG-4 Multi-Layer Bit-Sliced Arithmetic Audio Coding
報告學生: 游政勳
指導教授: 尤信程

2. Outline 1. Basic structure of Mutli-Layer Bit-Sliced Scalable
Audio Coding
2. MPEG-4 Bit-Sliced Arithmetic Coding(BSAC)
3. Conclusion

3. Basic structure of Mutli-Layer Bit-Sliced Scalable Audio Coding(1)
1. In order to reach fine-step scalability of audio
coding
2. Basically design the 16(base layer)
kbps scalable coder. But the bit-rate of the
enhancement layer can be chosen between 1 kbps
and a few dozen kbps with any resolution within
overall bit-rate,easily ………..bit-rate scalability
3. For each layer, only limited frequency band will be
coded (ex: the bandwidth of base layer is 3.5 kHz)
………..bandwidth scalability

4. Basic structure of Mutli-Layer Bit-Sliced Scalable Audio Coding(2)
4. The proposed encoder is simply version of AAC,and additional decoding process is not used in encoder

5. Basic structure of Mutli-Layer Bit-Sliced Scalable Audio Coding(3)
The priority of element to be encoded is determined according
to the relative importance in following figure

6. Basic structure of Mutli-Layer Bit-Sliced Scalable Audio Coding(4)
The rearrangement of the bit-patterns of the quantized
spectral data by bit-slice, and four-dimension vectors are
noiseless coded using arthmetic coding with fixed mode

7. MPEG-4 Bit-Sliced Arithmetic Coding(1)
1. Small step scalability of bit-sliced arithmetic coding
base layer: 16k bps
each enhancemeny layer: 1 kbps
2. In BSAC, the processing unit is coding band that
contain 32 spectral coefficients and use the same
arithmetic coding model index
3. Four dimension bit-sliced vector is divided into two
sub-vectors(sub-vector-0 and sub-vector-1)

8. MPEG-4 Bit-Sliced Arithmetic Coding(2)

9. MPEG-4 Bit-Sliced Arithmetic Coding(3)

10. MPEG-4 Bit-Sliced Arithmetic Coding(4)

11. MPEG-4 Bit-Sliced Arithmetic Coding(5)
4. Information about stereo coding and PNS are coded by different arithmetic models
5. Scale-factor is differentially coded related to fixed offset and then arithmetic coded using several arithmetic model
6. Coding scheme for the arithmetic model index of
the coding band is the same as scale-factor,but
use different arithmetic model

12. Conclusion 1. Arithmetic coding is more efficient than Huffman coding
2. Because of subband audio coding, scalability is
easilily implemented