United States Patent [191
`Hinder ks
`
`11111111111111111 1111111111111111111111111111111111111111111111111111111111
`US006041295A
`[11] Patent Number:
`[45] Date of Patent:
`
`6,041,295
`*Mar. 21, 2000
`
`(54] COMPARING CODEC lNPUT/OUTPUT TO
`ADJUST PSYCHO-ACOUSTIC PARAMETERS
`
`5,583,962 12/1996 Davis et al. ........................... 39512.38
`5,588,024 12/1996 Takano ................................... 395i238
`
`(75)
`
`Inventor: Larry W. H inderks, Holmdel, N.J.
`
`(73) Assignee: Cor por ate Computer Systems,
`Holmdel, N.J.
`
`[ * ] Notice:
`
`This patent issued on a continued pros(cid:173)
`ecution application filed under 37 CPR
`1.53( d), and is subject to the twenty year
`patent term provisions of 35 U.S.C.
`154(a)(2).
`
`(21) Appl. No.: 08/630,790
`
`[22] Filed:
`
`Apr. 10, 1996
`
`Related U.S. Application Data
`
`(63) Continuation of application No. 08/420,721, Apr. 10, 1995,
`and a continuation of application No. 08/419,200, Apr. 10,
`1995.
`Int. Cl.7
`. .. . ..................... . .. . .. . .. . .. . .. . .. .. . .. . .. . . GlOL 19/00
`[51)
`(52) U.S. Cl. .........
`. ........................................... 704/206
`(58) Field of Search ..................................... 395/2.09, 2.1,
`395/ 2.12- 2.15, 2.38, 2.39, 2.87; 704/200,
`201, 203-206, 229, 230, 278
`
`(56)
`
`References Cited
`
`U.S. PAIBNT DOCUMENTS
`
`4/1986 Alai .
`Re. 32,124
`4,624,012 11/1986 Lin et al. .
`4,972,484 11/1990 Theile el al. .
`5,151,998
`9/1992 Capps .................................... 395/2.87
`5,161,210 11/1992 Druyvesteyn et al. .
`2/1995 Freeburg .
`5,394,561
`5,493,647
`2/19% Miyasaka el al. .
`5,508,949
`4/19% Konstantinides ....................... 395/2.12
`5,515,107
`5/19% Chiang el al. .
`6/1996 Lokhoff et al. .
`5,530,655
`
`OTHER PUBLICPJlONS
`
`Brandenburg et al., "lSO-MPEG-1 Audio: A Generic Stan(cid:173)
`dard for Coding of High Quality Digital Audio", J. Audio
`Eng. Soc., vol. 42, No. 10, Oct. 1994, pp. 78~792 (pre(cid:173)
`sented Mar. 24-27, 1992, AES, Vienna, Austria).
`CDQl OOO Reference Manual, Rev. 3.3, May 1994.
`CDQ2000 Reference Manual, Rev. 6.92- 2, Jul. 1994.
`CDQ2001 Reference Manual, Rev. 2.2- 3, Aug. 1994.
`Primary Examiner~avicl D. Knepper
`Attorney, Agenl, or Firm-McAndrews, Held & Malloy,
`Ltd.
`
`[57]
`
`ABSTRACT
`
`An adjustable CODEC receives a signal and compresses a
`received audio signal based on a psycho-acoustic compres(cid:173)
`sion system. The psycho-acoustic compression system
`includes several psycho-acoustic parameters which may be
`adjusted by the user to optimize the compression system for
`a specific applicatfon, transmission medium, or end user, for
`example. The compression and the adjustment of compres(cid:173)
`sion parameters may occur simultaneously in real time
`without interruption of the compressed signal. Additionally,
`the parameters may be adjusted in smart groups of a plurality
`of parameters that are-, for example, sympathetic or are often
`adjusted together. An additional signal may also be com(cid:173)
`binoo with the compressed signal and che resultant combined
`signal may be transmitted over a single transmission path.
`For example, the additional signal may be multiplexed into
`the compressed data stream for TDMA transmission.
`Additionally, the parameters selected at a local, user(cid:173)
`adjusted CODEC may be transmitted to a plurality of remote
`CODEC for remote lL';e.
`
`44 Claims, 23 Drawing Sheets
`
`Microfiche Appendix Included
`(15 Microfiche, 912 Pages)
`
`--~
`
`Sto
`
`IPR2016-01710
`UNIFIED EX1005
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 1of23
`
`6,041,295
`
`)
`Audio (AES/EBU
`)
`Audio (Left
`Audio (Right
`)
`
`16
`12
`14
`
`10 -
`
`Synchronous Data
`
`34
`
`30
`
`-
`CAN 3 -
`
`Async 36
`H Optical ~ MUX
`hcANb
`H lime ~
`Code Rdr
`391
`
`ENCODER
`DSP
`~
`.
`
`18
`31
`33
`
`Isolators
`
`RS422/RS232
`RS485
`RS232
`
`35 Contact Closures
`
`3 7 Time Code
`
`Ancillary Data
`RS232
`
`
`Sync (AES/EBU )
`Audio (AES/EBU
`)
`Audio (left)
`Audio (Right)
`
`' -
`
`24
`22
`26
`28
`
`. •'I
`..,__ Digital
`
`..
`Digital
`~Interface ..
`Line
`Outputs
`40 Module
`.... 71
`70 '\
`
`i--
`
`Loop
`. Back
`Control
`
`i.--
`
`20
`
`90
`
`DECODER
`DSP
`
`..
`.·'I
`I+- Digital
`:.- Interlace ·1
`81 Module
`80
`
`Digital
`Line
`I
`nputs
`
`81
`
`38
`
`-
`
`~
`
`32
`
`Synchronous Data
`
`Async
`
`~
`
`25
`61
`63
`
`RS422/RS232
`RS485
`RS232
`65 Relay Outputs
`
`67 Time Code
`
`H Relays ~ De-MUX
`H Time
`1~
`
`Code Gen
`CAN 2 66
`
`69 Ancillary Data
`RS232
`
`~
`~ CAN 3
`64
`
`62
`
`51./
`
`LED
`DSP95
`
`Front Panel
`Key Pad
`
`Front Panel
`Remote Control
`RS232
`Rear Panel
`Remote Control
`(RS232/RS485)
`
`52
`
`54
`
`56
`
`-
`
`Control
`Processor
`
`50
`
`FIG. 1
`
`96
`
`58
`
`Front
`Panel
`LED
`Di
`splay
`
`
`F ront
`p
`anel
`LCD
`
`Di splay
`
`

`
`56 561 i54 54
`
`Rmt Ctl
`UART
`(LU 4)
`180
`
`1/0
`
`FP
`Rmt Ctl
`UART
`(LU 6)
`178
`
`61 31
`
`67 371
`SMPTE
`Time
`Code
`Interface
`172
`175 173
`
`63 33
`Other
`RS232
`UART
`(LU 2)
`170
`
`Anc
`Data
`UART
`(LU 0)
`168
`
`'
`
`71 81
`TA
`RS485
`RS422
`UART
`V.35
`(LU 1)
`X.21
`198
`176
`•
`195
`194
`v1s5 196---
`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 2 of 23
`
`6,041,295
`
`Remote
`Control
`
`Front Panel
`Remote
`Control
`
`RS485
`
`Digital
`Line
`Interface
`
`Time
`Code
`
`Other
`RS232
`
`r
`
`r
`
`197
`
`TA
`Control
`UART
`(LU 5)
`193
`
`Time
`Code
`UART
`(LU 7)
`174
`
`Anc
`Data
`69
`r-.
`
`1~39
`
`163
`
`164 165
`'
`162
`Anc
`Data
`Switch
`(CAN)
`•
`
`166
`
`167
`
`-
`a Op to
`14- Outputs -
`(DSPE) I (DSPR)
`
`Inputs
`
`65
`
`Relay
`
`Control
`"" Micro
`50
`192./'
`
`1551
`
`Keypad
`
`151
`
`!.
`Encoder
`DSP
`
`10
`T ·•111
`
`H.221
`DSP
`
`190
`
`191
`
`I
`
`!.
`Decoder
`DSP
`(DSPO}
`20
`I
`I
`
`123
`
`•
`OSPAnc
`Data
`UART
`(LU 3)
`169
`
`Vu/LEO/Hp
`97
`(DSPV) -
`DSP
`95
`
`T 96
`
`Sync
`Data
`Input
`18
`
`J
`
`Sample
`Rate
`Converter
`110
`
`101
`
`104
`
`Sample
`Rate
`Converter
`120
`
`!+-
`
`121
`
`122
`
`LED
`Array
`
`125
`
`147
`
`Hp
`DA
`Converter
`98
`
`-
`
`99
`
`H p
`
`18
`
`AD
`Converter
`
`100
`
`-
`SDI 12 r 14 l
`
`Analog
`Input
`
`AES/EBU
`Receiver
`
`103
`
`16
`
`Digital
`Input
`
`External
`Connector
`
`AES/EBU
`DA
`Converter Transmitter
`
`AES/EBU
`Receiver
`
`105
`
`126
`
`146
`
`26
`
`28
`
`22
`
`24
`
`•
`Sync
`Data
`Output
`25
`
`Analog
`Output
`
`Digital
`Output
`
`Digital Sync
`Input ~ 25
`
`FIG. 2
`
`SDO
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 3 of 23
`
`6,041,295
`
`Composite
`Ancillary
`Data Stream
`.
`38
`
`Ancillary
`Data
`Multiplexor
`
`30
`-
`
`ISO MPEG
`Audio Bit Stream
`
`40
`
`~
`
`ISO MPEG
`Encoder
`
`10 -
`
`-.
`
`
`
`FIG. 3
`
`39
`33
`31
`37
`35
`37
`
`Ancillary
`RS232
`RS485
`Time Code
`Switch Closures
`Time Code
`
`~
`
`12
`14
`
`Audio Left
`Audio Right
`
`ISOMPEG
`Audio Bit Stream
`
`22
`
`ISO MPEG
`Decoder
`
`Composite
`Ancillary
`Data Stream Ancillary
`Data
`23
`De-Mux
`
`60 -
`
`20 -
`
`FIG. 4
`
`Ancillary .
`RS232
`RS485
`Time Code
`Relay Contacts
`Time Code
`
`69
`63
`61
`67
`65
`67
`
`~
`
`Audio Left
`Audio Right
`
`26
`28
`
`~
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 4 or 23
`
`6,041,295
`
`LCD
`
`KEYPAD
`
`DIAL
`
`[[) lY] I ~c II o~F I IM. f
`a I G~I 11 J~l 11 M~O I I SWL I
`a I P~s 11 ~ 11 wr I lmTI
`I ENTER I [Q)[J[]] ~
`'
`
`FIG. 5
`
`DIAL MENU
`
`HP
`
`CUE
`
`LCD
`
`KEYPAD
`
`[[) LYl I ~ II DjF I ~ [EJ I wi.• I CE)~
`a I ~' II J~ II M~O I I SC*L I ~ [fil ~
`a l ~ l l~ ll wr l ISOOETI ~ ~ [§)
`IEHTER I [Q)[J[]] ~ I .wNT I ~ I OFF2 I
`
`FIG. 6
`
`LCD
`
`KEYPAD
`
`DIAL MENU
`
`HP
`
`CUE
`
`LVL MEAS
`
`FUNCTION
`
`r[[) lY] I ~c 11 DjF I ~ [EJ 1 ~·· CE) 1 ~ 1~ ~@)~
`a I Gr' II J~ II ~0 1 I lV>L I ~ [fil ~ l cau1 1 1~ 1 ~~
`a I p~s 11 nr 11 wr I lsosal ~ ~ [§) fl!AGE I QI] ~~
`IOOER I [Q)[J[]] ~ '™' ~ @ill lrur I~ (!!]~
`
`FIG . 7
`
`

`
`U.S. Patent
`
`Mar.21, 2000
`
`Sheet S of 23
`
`6,041,295
`
`Data
`
`. . MUSI CAM
`
`Data
`
`.
`
`Decoder
`DSP
`
`.
`.
`
`~Clock
`--.
`
`.
`
`Network
`Clock
`
`DA
`Converter
`
`. .
`
`Analog Left
`
`. .
`
`Analog Right
`
`.........
`
`Clock
`Generator
`
`200
`
`4
`
`. ..
`
`AES/EBU
`Transmitter
`
`. -,..
`
`AES/EBU
`Output
`
`FIG. 8
`
`Data
`
`Network
`Clock
`
`.
`... MUSICAM
`Decoder
`DSP
`
`.
`
`L
`
`Data .
`.
`J . ...
`
`_Clock
`
`,
`
`Rate
`Adaptor
`
`Data .
`.
`
`_Clock _
`,
`
`,.....__
`
`DA
`
`Converter -
`
`4
`
`Clock
`Generator
`
`.....__
`
`~
`AES/EBU
`Transmitter ~
`
`Internal
`Crystal
`
`..._
`
`FIG. 9
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 6 of 23
`
`6,041,295
`
`Data
`
`Network
`Clock
`
`MUSICAM
`Decoder
`DSP
`
`"
`
`~ ,..
`
`Data ...
`,..
`
`~Clock.
`
`- . -
`
`Data .
`
`,__
`
`Rate
`Adaptor
`,Clock.
`252 -
`-
`
`DA
`Converter
`254 -
`
`4
`
`Clock
`
`Generator -
`
`250
`
`---+
`
`AES/EBU -
`Transmitter
`256
`
`-
`
`AES/EBU
`Receiver
`258
`
`*'--
`
`FIG. 10
`
`

`
`U.S. Patent
`
`Mar.21, 2000
`
`Sheet 7 of 23
`
`6,041,295
`
`301
`'----\
`
`302
`~
`
`EHCOOER
`- ACE
`- DPLL
`- ccs
`- MUSIC.AM
`- G.722
`- ALG1
`- H.221
`- CCSIMUX
`
`- Pll
`- MONO
`- DMOOO
`- STEREO
`- JSTEREO
`- AES/EBU
`- ANALOG
`- SUM
`
`303
`~
`
`DECOOER
`- Pll
`- ACC.
`- DPLL
`- MONO
`- ccs
`- OMOO
`- WSlCAM
`- STEREO
`- JSTEREO - G.722
`- AlG1
`- FRAMED
`- BER
`- H.221
`- SUM
`- CCSIMUX
`
`STAM
`- SCUE 1
`- RC\.(1
`- OIF1
`- OIF2
`- OIF3
`- OIF4
`- OIFS
`- OIF6
`
`304
`
`302
`
`300J
`310
`
`HP~
`... AlllK> LEVEL
`'fN~rt°'lrYll ................... •
`R ~~ ~ ~ ~ ~ ~~ ~-- -- ~~---~•
`L .................. ~rco~~~ ................... .
`·20db -i
`·lOdb -4
`0 db -i
`·30 db -4
`
`R~ ~~~ ~~ ~ ~ ~ ~~ ~~~ ~ ~ - ~~~•
`0
`~
`~
`CORRELATION
`.---------S-TERE- gl-MA_G_E __ _...~---+ R
`
`308
`
`306
`
`FIG. 11
`
`304
`
`302
`
`300
`310
`
`HPS~
`.....................................................
`.........................................................
`.....................................................
`L
`OECOOfR LfVEL
`R .................................................................................
`+1
`·I
`0
`COAAEl.A TlOH
`c
`STEREO ~GE
`
`ENCODER lEVEL
`
`·20db ...
`
`·lOdb _.
`
`Odb _.
`
`R
`
`308
`
`306
`
`FIG. 12
`
`301
`302
`303
`~ ~ ~
`
`ENCOOER
`• PU
`• MONO
`• DMONO
`• JSTEREO
`• MUSICAM
`- G.722
`- AES/EBU
`- ANALOG
`
`OECOOfR
`- Ptl
`• MONO
`- DMONO
`• JSTEREO
`- MUSICAM
`- G.722
`-
`FRAMED
`- SER
`
`STATUS
`- SCUE 1
`• RCUE 1
`• OIF1
`• DIF2
`- Of3
`• OIF4
`- DIF5
`• OIF6
`
`L
`R
`
`L
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 8 of' 23
`
`6,041,295
`
`....---------)1
`
`Audio (AES/EBU) 1--------------.i
`Audio (Left) 1 - - - - - - - - - - - - -1 f
`Audio (Right) 1------------~
`RS422/RS232 1---- - -S-'y_n_ch_r_on_o_u_s _D_at_a_~
`•. •1
`.. Di9~a1
`ENCODER -
`Digital
`RS485~---
`i--. Interface ~ o~~Pn~ts
`DSP
`RS232
`Contact Closures H Optical L MUX 11 CAN 2 _
`Module
`"b..
`Time Code H nme L
`-
`Code Rdrr
`I
`
`Async
`
`Isolators r
`
`CAN3
`
`Ancillary Data
`RS232
`
`loop
`Back
`Control
`
`400
`
`404
`
`I /
`
`·1
`
`1)
`
`DSP
`
`DIM
`
`1+ 401 r-d- aX--..
`...
`
`405
`
`Sync (AES/EBU)
`Audio (AES/EBU)
`Audio (left) ~
`Audio (Right) ....
`
`RS422/RS232
`RS485
`RS232
`Relay Outputs
`
`Time Code
`
`Ancillary Data
`RS232
`
`N---+---1
`
`420
`
`LED
`DSP
`
`1+------'------1--~DECODER tt( daX
`Synchronous Data
`------1 Async
`L De-MUX +-
`~ Relays I
`1 lime
`I~
`Code Gen
`CAN2
`~ -
`CAN3
`
`400--i
`
`Satellite
`
`403
`..b
`Rec'r ._f[
`
`406
`
`402
`Front
`____ .., Panel
`LED
`Display
`
`Front Panel
`Key Pad
`
`~
`
`Front Panel
`Remote Control
`RS232
`Rear Panel
`Remote Control
`(RS232/RS485)
`
`.
`
`Control
`Processor
`
`Front
`i . - -- -....i Panel
`LCD
`Display
`
`FIG. 13
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 9 of 23
`
`6,041,295
`
`FIG. 14
`
`1012
`
`1010
`
`1040
`~ ..------.
`c==J
`
`1042
`
`ANALOG AUDIO
`SOURCE 1014__.- DECODER
`
`ENCODER
`
`/-1110 0 0 0 0 Il 0 I !<=ill
`
`1016
`
`1046
`
`)))
`
`REAL TIME
`EVALUATION
`
`FIG. 15
`
`ANALOG AUDIO INPUT SIGNAL
`
`1016
`
`ND CONVERTER
`
`1018
`
`1020
`
`ENCODER
`
`1012
`
`1022
`
`COMPRESSED
`AUDIO DIGITAL
`BIT STREAMS
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet l 0 of 23
`
`6,041,295
`
`POWER
`
`FIG. 16
`
`/1026
`
`1024
`
`FREQUENCY
`
`POWER
`
`/1026
`
`FIG. 17
`
`1028
`
`FREQUENCY
`
`POWER
`
`1055
`
`MASKING INDEX c ./ 1027
`
`FIG . 18
`
`./"'
`TONAL·> A+B"Z
`NOISE-> C+D"Z'-----1 H
`
`1029
`
`PP+G
`1029
`
`1050
`
`FREQUENCY
`
`1032
`
`1054
`
`

`
`U.S. Patent
`
`Mar. 21,2000
`
`Sheet 11 of 23
`
`6,041,295
`
`POWER
`
`FIG. 19
`
`1028
`
`FREQUENCY
`
`FIG. 20
`
`WAIT UNTIL USER
`PUSHES A KEY
`
`1060
`
`1062
`
`YES
`
`1064
`
`WAIT FOR USER TO
`ENTER A VALUE FOR
`PARAMETER" J"
`
`1066
`
`STORE THE VALUE
`ENTERED IN
`PARAMETER "J"
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 12 of 23
`
`6,041,295
`
`FIG. 21
`
`506
`
`510
`
`512
`
`516
`
`•
`
`•
`
`•
`
`•
`
`518
`
`MUX
`
`502
`
`ANALOG
`AUDIO
`
`504
`
`•
`
`•
`
`•
`
`•
`
`BPF31
`
`1--~ BPF32
`
`PAP
`
`514
`
`530 .........
`
`532
`Header
`
`534
`Audio Data
`
`536
`Ancillary Data
`
`546
`FIG. 22
`534
`
`548,
`
`552,
`SFSI
`
`I # Bit~bband I
`SB 1 b I I I
`
`538
`r--'---'
`
`540
`
`542-v"
`
`550~
`Scale Factor
`
`I· •• I SB32
`
`544-v"
`
`$832
`
`

`
`°' .... = ...
`
`tll
`\C
`N
`....
`......
`
`~
`
`....
`~ ....
`rJ'J =-~
`
`~ -N
`
`~
`
`~
`
`N g
`N .... ~
`~ = :-s
`
`~ = ....
`• -= ~ ....
`00
`0 •
`
`FIG. 23
`
`642
`
`"C°s46
`
`-
`
`I
`I
`I
`I
`i.-
`I
`636 I
`
`-
`
`-
`
`-
`
`652
`
`Calculator
`
`Energy
`
`~llr(~
`
`I
`I
`
`612
`
`LPFB
`
`614
`
`HPFB
`
`632
`
`Channel
`Right
`
`---IC -~ ./\,,,..-640
`
`644
`
`I
`I
`I
`620 I
`
`~
`
`A
`602
`
`a.r ? )
`~ r-
`
`I ·~
`
`'>
`
`A
`600
`
`r-
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 14 of 23
`
`6,041,295
`
`2400 '\.___
`
`, r
`
`Digitize Analog Audio Signal
`Received From Bandpass
`Filter For Subband
`
`2402"
`'--- Divide Digitized Signal For Subband
`From Band Pass Filter into Blocks
`
`2404 '\.___
`
`Determine Maximum Amplitude of
`Subband Signal For Each Block
`
`2406 '\.___
`
`Adjust &cale of Subband Signal
`For Each Block Until Signal Gain
`Corresponds To Quantizer Range
`
`FIG. 24
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 15 of 23
`
`6,041,295
`
`2502
`
`2504
`
`2506
`
`2508
`
`2510
`
`2512
`
`2514
`
`FIG. 25A
`
`Obtain Working Table of
`Psycho-Acoustic Parameters
`
`Obtain Segment of
`Analog Audio Signal
`
`Convert Digital Signal From Time
`To Frequency Domain in Bank Through
`FFT and Bank Transfer Function
`
`Calculate the Threshold
`of Hearing
`
`locate the Tonal Peaks
`Throughout Segment
`
`Remove the Tonal Peaks
`From Digital Signal
`
`Divide Signal into
`Critical Bands and Calculate
`Noise Maskers by Summing
`Energy in Each Critical Band
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 16 of 23
`
`6,041,295
`
`FIG. 258
`
`From FIG, 25A
`
`2516~
`
`Calculate Masking Skirts for
`Tonal and Noise Maskers Based
`on Parameters A - J and Amplitudes
`and Frequencies of Maskers
`
`2518~
`
`Combine Noise and Tonal Skirts
`and the Threshold of Hearing to
`Obtain the Global Masking Threshold
`
`2520~
`
`, ,.
`Divide GMT into Subbands
`Corresponding to Band Pass Filters
`and Locate Maximum & Minimum of
`GMT Within Each Subband
`
`2522
`
`Assign Quantization Level for Each
`~ Subband Based on an Amount of Noise
`Which May be Added to Subband
`Without Exceeding Minimum of GMT
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 17 of 23
`
`6,041,295
`
`Obtain GMT
`
`FIG. 26
`
`2600
`
`2602
`
`2604
`
`2606
`
`2608
`
`2612
`
`Set Current Subband To~
`
`Get First Masker In Subband
`
`Combine Current Masker With
`Threshold Of Hearing To Get GMT
`
`Get Next Masker
`
`2610
`
`Combine Next Masker With
`YES GMT Using 3db/6db Addition
`Rule (Parameter V)
`Consecutive Tonal Maskers
`
`Combine Next Masker
`With GMT
`
`YES
`
`2616
`
`Add Subband .0-3
`Adjustment
`Parameters W-Z
`
`2618
`
`NO
`
`Return
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 18 of' 23
`
`6,041,295
`
`Set Maximum Subband To Be Used For
`Selected Mode (Parameters S, MM and NN)
`
`Get Total Bit Pool For Joint Stereo Mode
`Or Stereo Mode Or Mono Mode
`
`Start With Subband 0 and First Channel
`
`2702
`
`2704
`
`2706
`
`FIG. 27
`
`NO
`
`Combine Safety Margin To Signal
`And Call Bit Allocation Routine
`
`2712
`
`(Parameter O)
`
`(FIG. 28)
`
`YES
`
`NO
`
`NO
`
`Record Current
`Subband Level
`As Boundary Crossing
`
`2722
`
`Return
`
`Increment
`Subband
`
`2726
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 19 ol' 23
`
`6,041,295
`
`FIG. 28
`
`Bit Allocation Routine
`
`Get Allocation And MNR Arrays
`Set Currents
`Step To First Step
`
`Get# Of Allocated Bits
`For Current Step
`
`Increment
`Step
`
`2818
`
`Get Peak/RMS (Parameter U )
`Max For Subband Signal
`
`Get MNR From Array For Current
`Step & Number Of Allocated Bits
`
`2816
`
`Record SGNL SB - Max
`MNRSTEP - GMT SB
`Or Current Channel
`And Subband In
`De Allocation Table
`
`YES
`
`2810
`
`Allocate Bits For Current
`Step To Subband Quantizer
`
`Update Allocated Bit
`Total
`
`Re tum
`
`2802
`
`2804
`
`2806
`
`2808
`
`2812
`
`2814
`
`

`
`U.S. Patent
`
`Mar. 21, 2000
`
`Sheet 20 of 23
`
`6,041,295
`
`2902
`
`2904
`
`Get List Of
`Acceptable Joint Stereo Boundaries
`
`Set Preferred Joint Stereo Boundary
`To Subband Where Bit Allocation
`Exceeded Available Bit Pool
`
`2906
`
`NO
`
`2908
`
`Set Preferred Joint Stereo Boundary
`To Joint Stereo Subband Minimum
`
`2910
`
`2912
`
`Set Final J/S Boundary From
`Prefered J/S Boundary And
`J/S Boundary Adjustment
`
`Shift Final J/S Boundary Upward
`To Next Higher Acceptable J/S
`Boundary From List
`
`FIG. 29
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 21 of 23
`
`6,041,295
`
`2522
`
`3000
`
`Assign Quantization Levels
`
`Allocate Bits In Steps To
`Each Subband Until
`Quantization Noise Falls
`Below GMT Minimum
`For Subband (FIG. 27)
`
`NO
`
`Demand
`
`Constant
`
`3006
`
`De Allocate Bits From
`Subbands Which Will Have
`Quantization Noise Level Closet
`(FIG. 31)
`To GMT Minimum For Subband
`
`(Parameter R)
`
`Use Demand Rate
`Minimum
`
`Assign Extra
`Bits To Subband
`
`Return
`
`FIG. 30
`
`

`
`U.S. Patent
`
`Mar.21,2000
`
`Sheet 22 of 23
`
`6,041,295
`
`3102
`
`De Allocation
`
`FIG. 31
`
`YES
`
`Determine J/S
`Boundary
`
`3104
`
`3106
`
`Obtain New Bit Pool
`Based On J/S Boundary
`
`3108
`
`Obtain Joint Stereo Array
`
`3110
`Allocate Bits To Subbands
`For Joint Stereo Frame
`(FIG. 27)
`With J/S Boundary
`
`NO
`
`Return
`
`3126
`
`YES
`
`Return
`
`

`
`U.S. Patent
`
`Mar. 21, 2000
`
`Sheet 23 of 23
`
`6,041,295
`
`2db
`3105
`
`2(BAR K)
`
`3(BAR K)
`
`6(BAR K)
`
`?(BARK)
`
`FIG. 32a
`
`FIG. 32b
`
`FIG. 33
`
`Channel
`
`Subband
`
`1
`2
`
`1
`
`7
`3
`
`7
`
`Difference Allocation
`Step
`Value
`2db
`3db
`
`3
`2
`
`4db
`
`2
`
`

`
`6,041,295
`
`1
`COMPARING CODEC INPUT/OUTPUT TO
`ADJUST PSYCHO-ACOUSTIC PARAMETERS
`
`RELATED APPLICATION
`
`This application is a continuation of application Ser. No.
`08/420,721, Filed Apr. 10, 1995, entitled "System for
`Adjustable Psycho-Acoustic Parameters In A Digital Audio
`CODEC" and a continuation of application Ser. No. 08/419,
`200 filed Apr. 10, 1995, entitled "System For Compression
`and Decompression of Audio For Digital Transmission".
`
`SOURCE CODE APPENDIX
`
`5
`
`Source code for the control processor of the present
`invention has been included as a microfiche SOURCE 15
`CODE APPENDIX.
`
`FIELD OF THE INVENTION
`
`The present invention relates generally to an audio
`CODEC for the compression and decompression of audio
`signals for transmission over digital facilities, and more
`specifically, relates to an audio CODEC that is program(cid:173)
`mable by a user to control various CODEC operations, such
`as monitoring and adjusting a set of psycho-acoustic
`parameters, selecting different modes of digital 25
`transmission, and downloading new compression algo(cid:173)
`rithms.
`
`2
`compression techniques attempt to model the human ear.
`These compression techniques are based on the recognition
`that much of what is given to the human ear is discarded
`because of the characteristics of the ear. For example, if a
`loud sound is presented to a human ear along with a softer
`sound, the ear will only hear the loud sound. As a result,
`encoding compression techniques can effectively ignore the
`softer sound and not assign any bits to its transmission and
`reproduction under the assumption that a human listener can
`10 not hear the softer sound even if it is faithfully transmitted
`and reproduced.
`Many conventional CODECs use perceptual coding tech(cid:173)
`niques which utilize a basic set of parameters which deter(cid:173)
`mine their behavior. For example, the coding technique must
`determine how soft a sound must be relative to a louder
`sound in order to make the softer sound a candidate for
`exclusion from transmission. A number which determines
`this threshold is considered a parameter of the scheme which
`is based on that threshold. These parameters are largely
`20 based on the human psychology of perception so they are
`collectively known as psycho-acoustic parameters.
`However, conventional CODECs which use perceptual
`coding have experienced limitations. More specifically,
`manufacturers of existing CODECs preprogram all of the
`CODECs operating variables which control the compression
`technique, decompression technique, bit allocation and
`transmission rate. By preprogramming the CODEC, the
`manufacturer undesirably limits the user interaction with the
`resulting CODEC. For example, it is known that audio can
`30 be transmitted by digital transmission facilities. These digi(cid:173)
`tal transmissions include digital data services, such as con(cid:173)
`ventional phone lines, ISDN, Tl, and El. Other digital
`transmission paths include RF transmission facilities such as
`spread spectrum RF transmission and satellite links.
`Although existing CODECs can transmit compressed
`audio signals via digital transmission facilities, any variables
`regarding the mode of transmission are preprogrammed by
`the manufacturer of the CODEC, thereby limiting the
`40 CODECs use to a single specific transmission facility.
`Hence, the user must select a CODEC which is prepro(cid:173)
`grammed to be compatible with the user's transmission
`facility. Moreover, existing CODECs operate based on
`inflexible compression and bit allocation techniques and
`45 thus, do not provide users with a method or apparatus to
`monitor or adjust the CODEC to fit the particular user's
`wants and needs. Accordingly, users must test CODECs with
`different compression and bit allocation techniques and then
`select the one device which has the features or options so
`50 desired, e.g. satellite transmission capabilities.
`Moreover, standard coding techniques have been devel(cid:173)
`oped in order to ensure interoperability of CODECs from
`different manufacturers and to ensure an overall level of
`audio quality, thereby limiting the CODEC's use to a single
`55 specific transmission facility. One such standard is the
`so-called ISO/MPEG Layer-II compression standard, for the
`compression and decompression of an audio input. This
`standard sets forth a compression technique and a bit stream
`syntax for the transmission of compressed binary data. The
`60 ISO/MPEG Layer-II standard defines a set of psycho(cid:173)
`acoustic parameters that is useful in performing compres(cid:173)
`sion. U.S. Pat. No. 4,972,484, entitled "Method of Trans(cid:173)
`mitting or Storing Masked Sub-band Coded Audio Signals,"
`discloses the ISO/MPEG Layer-II standard and is incorpo-
`65 rated by reference.
`However, conventional CODECs do not use a uniform set
`of parameters. Each CODEC manufacturer determines their
`
`35
`
`BACKGROUND OF THE INVENTION
`
`Current technology permits the translation of analog
`audio signals into a sequence of binary numbers (digital).
`These numbers may then be transmitted and received
`through a variety of means. The received signals may then
`be converted back into analog audio signals. The device for
`performing both the conversion from analog to digital and
`the conversion from digital to analog is called a CODEC.
`This is an acronym for COder/DECoder.
`The cost of transmitting bits from one location to another
`is a function of the number of bits transmitted per second.
`The higher the bit transfer rate the higher the cost. Certain
`laws of physics in human and audio perception establish a
`direct relationship between perceived audio quality and the
`number of bits transferred per second. The net result is that
`improved audio quality increases the cost of transmission.
`CODEC manufacturers have developed technologies to
`reduce the number of bits required to transmit any given
`audio signal (compression techniques) thereby reducing the
`associated transmission costs. The cost of transmitting bits is
`also a function of the transmission facility used, i.e.,
`satellite, PCM phone lines, ISDN (fiber optics).
`A CODEC that contains some of these compression
`techniques also acts as a computing device. It inputs the
`analog audio signal, converts the audio signal to a digital bit
`stream, and then applies a compression technique to the bit
`stream thereby reducing the number of bits required to
`successfully transmit the original audio signal. The receiv(cid:173)
`ing CODEC applies the same compression techniques in
`reverse (decompression) so that it is able to convert the
`compressed digital bit stream back into an analog audio
`signal. The difference in quality between the analog audio
`input and the reconstructed audio output is an indication of
`the quality of the, compression technique. The highest
`quality technique would yield an identical signal reconstruc(cid:173)
`tion.
`Currently, the most successful compression techniques
`are called perceptual coding techniques. These types of
`
`

`
`6,041,295
`
`3
`own set of psycho-acoustic parameters either from a known
`standard or as modified by the manufacturer in an attempt to
`provide the highest quality sound while using the lowest
`number of bits to encode audio. Once the manufacturer
`selects a desired parameter set, the manufacturer programs
`values for each of the parameters. These preprogrammed
`parameter values correspond to the manufacturer's percep(cid:173)
`tion of an optimal audio quality at the decoder.
`However, in conventional CODECs, users typically are
`unaware of the existence or nature of these parameters.
`Further, the user has no control over the parameter values.
`As a result, users were required to test different CODECs
`from different manufacturers and then select the CODEC
`that met the user's requirements or that sounded best to the
`user.
`Typically, conventional CODECs utilize standard param(cid:173)
`eters which have been accepted by the International Stan(cid:173)
`dards Organization (ISO) and have been adopted as part of
`the International Standards Organization. Motion Picture
`Experts Group (ISO/MPEG) Layer-II compression standard. 20
`However, the ISO/MPEG Layer-II standard has met with
`limited acceptance since these parameters do not necessarily
`provide CD quality output. The ISO/MPEG Layer-II param(cid:173)
`eters are determined and set based on the average human ear.
`The parameters do not account for the variations between 25
`each individuals hearing capabilities. Hence, the conven(cid:173)
`tional standards and CODECs do not afford the ability for
`users to tune their CODEC to the user's individual subjec(cid:173)
`tive hearing criteria. Nor are conventional CODECs able to
`meet changing audio needs and to shape the overall sound of 30
`their application.
`A need remains within the industry for an improved
`CODEC which is more flexible, programmable by the user,
`and which overcomes the disadvantages experienced here(cid:173)
`tofore. It is an object of the present invention to meet this 35
`need.
`
`15
`
`4
`It is a related object of the present invention to provide an
`audio CODEC that is programmable by a user to transmit
`compressed digital bit streams over a digital data service.
`It is a further related object of the present invention to
`5 provide an audio CODEC that is programmable by a user for
`transmission of compressed digital bit streams over any of
`Tl, El and ISDN lines or over RF transmission facilities.
`It is yet another related object of the present invention to
`provide an audio CODEC that is user programmable for
`10 transmission of compressed digital bit streams via satellite.
`It is a further object of the present invention to provide an
`audio CODEC for transmission of asynchronous data
`together with the transmission of compressed audio.
`It is still a further object of the present invention to
`provide an audio CODEC that utilizes the multiple audio
`compression and decompression schemes.
`It is still another object of the present invention to provide
`an audio CODEC which allows a user to select one of
`several stored audio compression techniques.
`It is still another object of the present invention to provide
`an audio CODEC that is remotely controlled by a host
`computer.
`It is still another object of the present invention to provide
`an audio CODEC for monitoring either the encoder input
`signal or the decoder output signal with the use of head(cid:173)
`phones.
`It is still another object of the present invention to provide
`an audio CODEC with safeguards for automatically select(cid:173)
`ing a second transmission facility if a first user selected
`transmission facility fails.
`It is yet another object of the present invention to provide
`an audio CODEC that can be controlled by inputting control
`commands into a key pad on the front panel of the CODEC.
`It is related object of the present invention to provide an
`audio CODEC having a user interface to control and pro(cid:173)
`gram the audio CODEC through the use of a graphics
`display on the front panel.
`It is still another related object of the present invention to
`40 provide for connection of a personal computer to the audio
`CODEC for controlling the input of program information
`thereto.
`It is still another object of the present invention to provide
`bi-directional communication between two audio CODECs.
`It is still another object of the present invention to provide
`an audio CODEC that can be interfaced to a local area
`network.
`It is yet another object of the present invention to provide
`an audio CODEC that will provide programmed information
`to users through the use of indicators on the front panel of
`the CODEC.
`It is yet another object of the present invention to provide
`an audio CODEC that can send non-audio compressed
`55 information including text, video and graphic information.
`It is still another object of the present invention to provide
`an audio CODEC that can store and retrieve information on
`and from an electronic storage medium or a disk drive.
`It is still another related object of the present invention to
`60 provide an audio CODEC that can transmit control infor(cid:173)
`mation along with the textual video and graphic information.
`It is still a further object of the present invention to
`provide digital audio compression techniques that yield
`improved and preferably CD quality audio.
`It is a related object of the present invention to provide a
`compression scheme that yields better audio quality than the
`MPEG compression standard.
`
`45
`
`OBJECTS OF THE INVENTION
`It is an object of the present invention to provide a
`programmable audio CODEC that can be monitored, con(cid:173)
`trolled and adjusted by a user to control the various functions
`of the CODEC.
`It is another object of the present invention to provide an
`audio CODEC that is programmable by a user to transmit
`compressed digital bit streams over various user selected
`digital transmission facilities.
`It is an object of the present invention to provide a user
`programmable audio CODEC with a plurality of psycho(cid:173)
`acoustic parameters that can be monitored, controlled, and 50
`adjusted by a user to change the audio output from the
`CODEC.
`It is a related object of the present invention to provide an
`audio CODEC with new psycho-acoustic parameters.
`It is a further related object of the present invention to
`provide an audio CODEC where the psycho-acoustic param(cid:173)
`eters are changed by knobs on the front panel of the
`CODEC.
`It is another related object of the present invention to
`provide an audio CODEC where the psycho-acoustic param(cid:173)
`eters are changed by a keypad on the front panel of the
`CODEC.
`It is still a further related object of the present invention
`to provide an audio CODEC with a personal computer
`connected thereto to adjust the psycho-acoustic parameters 65
`by changing graphic representations of the parameters on a
`computer screen.
`
`

`
`5
`
`20
`
`30
`
`diagram illustrating the interconnection
`modules in accordance with a preferred
`
`5
`It is still another related object of the present invention to
`provide CD quality audio that achieves-a 12 to 1 compres(cid:173)
`sion ratio.
`
`6,041,295
`
`6
`FIG. 7 is another example of a front panel user keypad
`layout in accordance with a preferred embodiment of the
`present invention.
`FIG. 8 is a block diagram showing the decoder output
`SUMMARY OF THE INVENTION
`timing with the AES/EBU sync disabled or not present and
`using normal timing in accordance with a preferred embodi(cid:173)
`The present invention provides a CODEC which holds
`ment of the present invention.
`several compression algorithms and allows the user easily to
`FIG. 9 is a block diagram showing the decoder output
`download future audio compression algorithms as needed.
`timing with AES/EBU sync disabled or not present using
`This makes the present CODEC very versatile and prevents
`10 internal crystal timing in. accordance with a preferred
`it from becoming obsolete.
`embodiment of the present invention.
`The pre