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[wdmaudiodev] some issues with sysvad sample - help appreciated

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Helloguys, IamdevelopinganAPOforacustomaudioprocessingeffect.Likemany othersIhavebeganwithsysvad. AfterovercomingsomebasicissuesIhavesuccessfullybuiltallmodules usingVS15. Inowhavethefollowingmodulesbuilt: KeywordDetectorContosoAdapter.dll PhoneAudioSample.sys ...

[wdmaudiodev] Re: some issues with sysvad sample - help appreciated

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Theprojectthatbuilttabletaudiosample.sysshouldalsohave“built”(really, stamped)tabletaudiosample.inf. From:GilShefer Sent:Saturday,April1,20172:42PM To:wdmaudiodev@xxxxxxxxxxxxx Subject:[wdmaudiodev]someissueswithsysvadsample-helpappreciated Helloguys, ...

[wdmaudiodev] Re: Where to report issues with the Windows 10 UAC2 audio driver?

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Let’ssee… Yes,thedevshaveaskedifthisreprosonthelatestInsiderbuild (currentlythelatestInsiderbuildis16299) Yes,it’sexactlythesamebehaviorwithInsiderbuild16299.ShouldIprobably openasupportincidenttogetincontactwiththedevelopers? ...

[wdmaudiodev] Re: Where to report issues with the Windows 10 UAC2 audio driver?

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Thanks,Ihaveconveyedthatinformationtothedevelopers. Youcouldcertainlyopenasupportcaseifyouwantedtoexpeditethings.If youdo,pleasetellthesupportengineerthisisabout“OSbug13834139.” From:FranzDetro Sent:Tuesday,October10,201711:35PM To:wdmaudiodev@xxxxxxxxxxxxx Subject:[wdmaudiodev]Re:WheretoreportissueswiththeWindows10UAC2 audiodriver? ...

[wdmaudiodev] Re: Windows Real Time : suggestion to Microsoft Kernel Developers

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Hello, OneyearafterIcomebacktothissuggestion,toturnWindowsinaRTmode (enoughRTforRTaudioImean), afterhavingthoughttodifferentpossibilitieslikethreadRT characteristics,CoreAllocationetc…. ...

[wdmaudiodev] Re: Windows Real Time : suggestion to Microsoft Kernel Developers

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CanyousubmitthisasasuggestionviaFeedbackHub? ________________________________ From:wdmaudiodev-bounce@xxxxxxxxxxxxxwdmaudiodev-bounce@xxxxxxxxxxxxxon behalfofVincentBurel(VB-Audio)vincent.burel@xxxxxxxxxxxx Sent:Thursday,October12,201712:49:03AM To:wdmaudiodev@xxxxxxxxxxxxx Subject:[wdmaudiodev]Re:WindowsRealTime:suggestiontoMicrosoftKernel Developers ...

[wdmaudiodev] Re: Windows Real Time : suggestion to Microsoft Kernel Developers

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Idon’tknowthis… …couldnotitbesimplertoforwardthismailtotherightspeopleinstead ? Thanksbyadvance Regards VincentBurel ...

[wdmaudiodev] Re: Windows Real Time : suggestion to Microsoft Kernel Developers

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No,sorry ________________________________ From:wdmaudiodev-bounce@xxxxxxxxxxxxxwdmaudiodev-bounce@xxxxxxxxxxxxxon behalfofVincentBurel(VB-Audio)vincent.burel@xxxxxxxxxxxx Sent:Saturday,October14,20172:30:16AM To:wdmaudiodev@xxxxxxxxxxxxx Subject:[wdmaudiodev]Re:WindowsRealTime:suggestiontoMicrosoftKernel Developers ...

[wdmaudiodev] Windows Clock Compensation

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Weallknowthatcrystalsarenotperfect. Evenifbothendsofan audioconversationagreetoanominal48kHzsamplingrate,witha100ppm crystal,theactualratemightbebetween47,995and48,005samplesper second. Andiftheinputandtheoutputareondifferentboards,they mightbeatoppositeendsofthatrange. Andyet,wedonothear complaintsfromusersofcheapcommodityhardwareaboutperiodic glitchesintheirvideoconferences. Whyisthat? IstheAudioEnginecompensatingforthis? Isit monitoringaveragebyte-per-secondratesoverlongperiodsanddoing ...

[wdmaudiodev] Re: Windows Clock Compensation

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Severalthings: 1.Ofteninputsandoutputsarefromandtothesameaudioperipheral,which usesthesameclockforrenderandcapture.Soalthoughtheclockmaybeoff (e.g.,47.995kHzinsteadoftrue48kHz),boththeinputclockandtheoutput clockareoffinthesamedirectionbythesameamount. 2.Incaseslikevideoconferencingwheretheinputandoutputareon totallydifferentdevice,skewcompensationisdoneinsoftware.Forexample, ...

[wdmaudiodev] Re: Windows Clock Compensation

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Firmwareengineerhere. One possible solution we implemented for usb-audio using synchronous mode was to adjust the reference clocks on the micro-controller in realtime by a very small amount to ensure that there are no underflow/overflow conditions that manifest themselves as pops/clicks(we did have pops and clicks otherwise) ...

[wdmaudiodev] Re: Windows Clock Compensation

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UACinheritsfromUSBbasespec. Specifically,forthistopic,ISOtransfer types::Async,Sync,Adaptive. ItistheresponsibilityforUACdeviceto maintainbuffermanagement(onemethodoranother):: -ISOAsync-explicitvsimplicitfeedbackmechanism---audiobuffersare maintainedviathedevice explicitlytellingthehostthatitisonesample ahead(-a),onesamplebehind(+1),orinlockstep(0)viaseparateISO feedbackendpoint,orimpliedbythebehavioroftherecordingstream(dynamic slightadjustmentsasnotedforexplicit) ...

[wdmaudiodev] Re: Windows Clock Compensation

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AkshaykeertiSharmawrote: Onepossiblesolutionweimplementedforusb-audiousingsynchronous modewastoadjustthereferenceclocksonthemicro-controllerin realtimebyaverysmallamounttoensurethatthereareno underflow/overflowconditionsthatmanifestthemselvesas pops/clicks(wedidhavepopsandclicksotherwise) Howwouldyouknow? BymonitoringthelevelsinyouronboardFIFOs?  Thisisanextremelytrickyproblem,becauseeventhoughaudioseemsto ...

[wdmaudiodev] Re: Windows Clock Compensation

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Idon'tknowhowothersdoit,butthisclocksynchronizationmethod(ISO Sync)isveryeasytodoinhardware yousimplyinfertheUSBhost'sclockbyaccuratelytimingSOFSOFinhardware (notviaMCUISR)anddynamically(butslowly)adjustyourlocalmasteraudio clocktomanageaudiobuffers...youcanachieveaveryaccuratewaterlevel using thismethodof synchronization ISOAsyncisacompletelydifferentsynchronizationmethod,buthasthe advantageoflowjitteraudiomasterclock(since the synchronizationmethod aboveisremovedand feedbackissolvedotherways) It'sinnowway extremelytrickyproblem...but,intheearlydaysofUACfor ...

[wdmaudiodev] Re: Windows Clock Compensation

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Right,thisishowyouslaveyourbuffertransferstotheeventualADCorDAC whiledealingwithjitter. Tim’squestioniswhathappensifyouhaveapipelinewithanADCononeend, andaDAContheother,andthereisskewbetweenthem. ________________________________ From:wdmaudiodev-bounce@xxxxxxxxxxxxxwdmaudiodev-bounce@xxxxxxxxxxxxxon behalfofTroyGentrydmarc-noreply@xxxxxxxxxxxxx Sent:Wednesday,October18,20173:38:39PM ...

[wdmaudiodev] Re: Windows Clock Compensation

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programmatically,I'ddiscoverthebDelaylatencyparameterfromtheADCand fromtheDAC(assumingnotsamephysicaldevice)andusethosenumbersfor worstcaseanalysis typically,USBdeviceis goingtoreportanywherefrom1-3msecforbDelay.... PLUSthere'ssimilarbDelayforUSBhostsystem. Ithinksomesoftwarelike  ProLogicwilltellyouroundtripdelayforsame device,notsureaboutround tripdelaytimingfordifferentdevices... so,yeahabovemypaygradehere,sorryguys From:MatthewvanEerdedmarc-noreply@xxxxxxxxxxxxx ...

[wdmaudiodev] Re: Windows Clock Compensation

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Yes,wearemonitoringthemicrocontrollerqueueslivetoensurethatthereis noproblem.IfIremembercorrectlytheusbaudio1.0specweareusing transmits48samples/ms(48khz)inourimplementation.Makingaverysmallchange toourI2Sreferenceclock(thisiswhatdrivestheaudioouttoaspeaker essentially)controlstheFIFOqueue.Thetrimsettingonthemicroisaccurate enoughtoensurepreciseenoughchangestotheclocktosometimesevenmatch theinputdatastream. Anotherwayistosynctotheusbframestartofframewhichresultsingetting thesameinformation.Youwouldsynctothestartframeandup/downtheclock ...

[wdmaudiodev] Re: Windows Clock Compensation

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doingitthisway,isasTimsaysanextremelytrickyproblem-agreeddoing itthisway,willlikelyproducenoticeableaudiblesynchronizationclocking artifactsintheactualaudiostreamitself(dependingontheactualclock mismatchbetweentheUSBHostandtheUSBdevice) ifthisisallonehasfortheiraudiobuffermanagementmechanism,then switchingtoASYNCsynchronizationmethodwouldbehighlyrecommended. From:AkshaykeertiSharmaasharma@xxxxxxxxxxxxxxxxxxxxx To:wdmaudiodev@xxxxxxxxxxxxx Sent:Wednesday,October18,20174:51PM ...

[wdmaudiodev] Re: Windows Clock Compensation

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Ifyouhavetheproperhardware(i.e.afractionalPLL)theadjustmentsyoucan maketothelocalclockareextremelyprecise(typically0.01ppm)Ifyouthen alsoimplementalow-passfilterbehaviorontheclockadjustmentalgorithmand deployveryextensiveaveraging,youcanachieveaudioclockqualitylevels thatarebeyondwhatcurrentADCsandDACsrequire. Goingwiththeasynchronousmodeactuallyshifts(notsolves)theproblemto theHost.IftheHosthassufficientlysophisticatedasynchronoussamplingrate algorithmsavailable,thenthatmaybeagoodsolution.Butdonotassumethat allqualityconcernsevaporatewhenyouswitchtoasyncmode. ...

[wdmaudiodev] Re: Windows Clock Compensation

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inthereliesthetruth,the opertativephrasehereisIfyouhavetheproper hardware...thepreviousposterisattemptingtosolvethisageoldproblem mostlyinsoftware...also,aSOCthatnativelyhasanIntegerPLL(alongwith afewothergoodies)canactually(hasactually)solvethisproblem,andfor bothclocktrees,andfromasingleexternalcrystal...soonereallycanpull arabbitoutofahat;) Ihaven'tranintomanyearsthatcandothePepsichallengewithASYNCvs SYNC(properlydoneinhardware,asGeertlaysoutbelow)andactuallytellthe difference,butIhavehadtheprivilegeofmeetingonesuchsole(ataworld renownedmusicstudio)thatcouldhearthedifference,itwastrulyanamazing ...
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