1.1.1RulesandGuidelines
1.2RequirementsoftheStandard
RequirementsoftheStandard
Level3containstheguidelinesforspecificfamiliesofDSPs.Today,therearenoagreed-uponguidelines
foralgorithmswithregardtotheuseofprocessorresources.Theseguidelineswillprovideguidanceon
thedosanddon'tsforthevariousarchitectures.Thereisalwaysthepossibilitythatdeviationsfromthese
guidelineswilloccur,butthenthealgorithmvendorcanexplicitlydrawattentiontothedeviationinthe
relevantdocumentationormoduleheaders.
Theshadedboxesrepresenttheareasthatarecoveredinthisversionofthespecification.
Level4containsthevariousverticalmarkets.Duetotheinherentlydifferentnatureofeachofthese
businesses,itseemsappropriateforthestakeholdersineachofthesemarketstodefinetheinterfacesfor
groupsofalgorithmsbasedontheverticalmarket.Ifeachuniquealgorithmwerespecifiedwithan
interface,thestandardwouldneverbeabletokeepupandthusnotbeeffective.Itisimportanttonote
thatatthislevel,anyalgorithmthatconformstotherulesdefinedinthetopthreelevelsisconsidered
eXpressDSP-compliant.
TheTMS320DSPAlgorithmStandardspecifiesbothrulesandguidelines.Rulesmustbefollowedin
orderforsoftwaretobeeXpressDSP-compliant.Guidelines,ontheotherhand,arestronglysuggested
recommendationsthatshouldbeobeyed,butarenotrequired,inorderforsoftwaretobe
eXpressDSP-compliant.
ThissectionliststherequiredelementsoftheTMS320DSPAlgorithmStandard.Theserequirementsare
usedthroughouttheremainderofthedocumenttomotivatedesignchoices.Theyalsohelpclarifythe
intentofmanyofthestatedrulesandguidelines.
•Algorithmsfrommultiplevendorscanbeintegratedintoasinglesystem.
•Algorithmsareframework-agnostic.Thatis,thesamealgorithmcanbeefficientlyusedinvirtuallyany
applicationorframework.
•Algorithmscanbedeployedinpurelystaticaswellasdynamicrun-timeenvironments.
•Algorithmscanbedistributedinbinaryform.
•Integrationofalgorithmsdoesnotrequirerecompilationoftheclientapplication,although
reconfigurationandrelinkingmayberequired.
AhugenumberofDSPalgorithmsareneededintoday'smarketplace,includingmodems,vocoders,
speechrecognizers,echocancellation,andtext-to-speech.Itisnotpossibleforaproductdeveloper,who
wantstoleveragethisrichsetofalgorithms,toobtainallthenecessaryalgorithmsfromasinglesource.
Ontheotherhand,integratingalgorithmsfrommultiplevendorsisoftenimpossibleduetoincompatibilities
betweenthevariousimplementations.InordertobreakthisCatch-22,eXpressDSP-compliantalgorithms
fromdifferentvendorsmustallinteroperate.
Dozensofdistinctthird-partyDSPframeworksexistinthetelephonyverticalmarketalone.Eachvendor
hashundredsandsometimesthousandsofcustomers.Yet,nooneframeworkdominatesthemarket.To
achievethegoalofalgorithmreuse,thesamealgorithmmustbeusableinallframeworks.
Marketplacefragmentationbyvariousframeworkshasalegitimatetechnicalbasis.Eachframework
optimizesperformanceforanintendedclassofsystems.Forexample,clientsystemsaredesignedas
single-channelsystemswithlimitedmemory,limitedpower,andlower-costDSPs.Asaresult,theyare
quitesensitivetoperformancedegradation.Serversystems,ontheotherhand,useasingleDSPto
handlemultiplechannels,thusreducingthecostperchannel.Asaresult,theymustsupportadynamic
environment.Yet,bothclient-sideandserver-sidesystemsmayrequireexactlythesamevocoders.
Itisimportantthatalgorithmsbedeliverableinbinaryform.Thisnotonlyprotectsthealgorithmvendor's
intellectualproperty;italsoimprovesthereusabilityofthealgorithm.Ifsourcecodewererequired,all
clientswouldrequirerecompilation.Inadditiontobeingdestabilizingfortheclients,versioncontrolforthe
algorithmswouldbeclosetoimpossible.
SPRU352G–June2005–RevisedFebruary2007Overview11
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