MPEG Surround

download MPEG Surround

of 21

  • date post

    23-Feb-2016
  • Category

    Documents

  • view

    38
  • download

    0

Embed Size (px)

description

Student: Shang-Yu Yeh Adviser : H.-M. Hang 2007/12/17. MPEG Surround. Outline. MPEG Surround Introduction T/F Resolution and DataMode Adaptive Parameter Smoothing Experimental Results. MPEG Surround Introduction. - PowerPoint PPT Presentation

Transcript of MPEG Surround

MPEG Surround

MPEG SurroundStudent: Shang-Yu Yeh Adviser : H.-M. Hang 2007/12/17

OutlineMPEG Surround IntroductionT/F Resolution and DataModeAdaptive Parameter SmoothingExperimental ResultsMPEG Surround IntroductionLow-bitrate parametric coding technology for multi-channel audio signalBackward compatibility to stereo equipmentExploits inter-channel differences in level, phase and coherence equivalent to the spatial cues to capture the spatial image of a multi-channel audio signalSpatial cues: CLD, ICC, CPC

Spatial Audio Coding

Encoder:Decoder:Enc:Dmxmono strereomtx-surround compatible stereodmxmp3 aaccodingdmxspatial parametersmultiplexerdmxparabitstreamstereoignoreinfoDEC:Demuxdmxcue

Enc:The resulting down mix has a mono, stereo, or matrixed-surround compatible stereo format.This down mix can be encoded with any conventional mono or stereo compression method.All perceptually relevant information that is lost by the down-mix process is captured by means of spatial 'parameters'.Conventional audio decoders will ignore this additional information layer and hence full backwards compatibility is assured.Dec:the conventional (mono or stereo) bit stream and parameter bit stream are separated by a demultiplexer.

4MPEG Surround EncoderArchitecture:

SACMPEG Encoder(N-channel)time/frequency transformbandT/F domainNchanneldownmix(for ex: to 2-channel)transformtime domaindecoderbitratevery low bitrate

5T/F Resolution and DataModeParameter extractionreduce the accuracy of samples

71 hybrid subbandsparameterbandsparametersetsT/F Resolution and DataModeNew Architecture:

TimeResolutionDecisionDataMode & Freq ResolutionDecisionAdaptive Parameter SmoothSACMPEG Encoder(N-channel)time/frequency transformbandT/F domainNchanneldownmix(for ex: to 2-channel)transformtime domaindecoderbitratevery low bitrate

7T/F ResolutionResolution refers to the number of parameters 0 1 2 3 0Time(ps)Frequency(pb)pbStrideTime Resolution DecisionChoose the number of parameter sets for a frameCan be fixed or variable 0 1 2 3 0 1 2 3 DataMode DecisionExploit the correlation between subsequent sets4 modes: default, keep, interpolation and lossless

0 1 2 3 parameter set 0 1 2 data set

Freq Resolution DecisionChoose a stride that make the decoding error minimumExploit correlation between bandspbStride can be: 1, 2, 5, 28

0 1 2 data setstridestridestride

Freq Resolution DecisionPairing: grouping of 2 parameter subsets to share some data (QP, pbStride)Pairing of non-neighboring sets will not have gain 0 1 2 data setpairCombination of 2 modules

Adaptive Parameter SmoothingFor artifacts from coarse quantization and low up-date rate of spatial cues Especially in the case of stationary and tonal signalsFirst order IIR filtering of the parameter bandsspectoolquality14Adaptive Parameter Smoothing

AB

Smooth strengh:Wl-1param-setmtxWlkonjparam-setdatamtxmtxparam-setmtxAsetslotBencconfigbsmoothencoderconfigcase15Adaptive Parameter SmoothingConfigure for each parameter setError estimation:

Parameter normalization:

Experimental ResultsAdd DataMode and Freq Resolution Decision Modules without any lossBitrate reduction(%):

ps1ps2ps4Input014.222.522.36Input0225.1221.0920.07Input036.673.893.54Input043.882.522.28Input054.632.772.57(pb=10)Experimental ResultsDataMode Decision:

Bitrate reduction(%):TheoreticalExperimentalInput0159.0344.70Input0275.7455.68Input0366.8548.05Input0459.5244.11Input0563.3747.07(ps=1, pb=10)errorerror18Experimental ResultsFreq Resolution Decision:

Bitrate reduction(%):TheoreticalExperimentalInput0130.0816.29Input0220.838.58Input0314.116.80Input0432.3517.29Input0528.1115.35(ps=1, pb=10)Experimental ResultsOverall Bitrate reduction(%):

ps1ps2ps4Input0153.7140.2028.99Input0259.4956.6655.97Input0351.5841.2430.34Input0453.7742.4729.96Input0555.1946.5935.34(pb=10)Experimental ResultsInput01 (LS)Input02 (L)Input02(R)Original

No smooth

Smooth with normalized errorAdditional bit rate0.005 kB/s0.00498 kB/s0.00498 kB/s

T/F Transform

T/F Transform

T/F Transform

Downmix

SpatialParameterEstimation

AudioEncoder

CompressedAudioBitstream

Spatial Parameters

F/T Transform

F/T Transform

MPEG Surround Encoder

T/F Transform

T/F Transform

T/F Transform

Downmix

SpatialParameterEstimation

AudioEncoder

CompressedAudioBitstream

Spatial Parameters

F/T Transform

F/T Transform

MPEG Surround Encoder