SimPhonics, Inc. FXDirect Audio System for V+
SimPhonics, Inc. What Is FXDirect ® Audio Subsystem Add-on to V+ –Currently built-in Consists of Objects for Manipulation of Audio –Synthesis/sampling –Mixing Audio Subsystem Add-on to V+ –Currently built-in Consists of Objects for Manipulation of Audio –Synthesis/sampling –Mixing
SimPhonics, Inc. What Is FXDirect ® V+ Wrapper Around DirectSound® Can be used with advanced hardware (SMx) –FXDirect alone – 4 channels (OTS sound Cards) –FXDirect with SMx – Up to 50 Channels V+ Wrapper Around DirectSound® Can be used with advanced hardware (SMx) –FXDirect alone – 4 channels (OTS sound Cards) –FXDirect with SMx – Up to 50 Channels
SimPhonics, Inc. Basic Sampling Theory Evolution of Audio Generation Sampling Versus Synthesis Microsoft DirectX FXDirect Demo and Hands-On Overview
SimPhonics, Inc. Basic Sampling Theory “Sampling” is Digitizing Waveforms Finite sample rate Typical 22khz, up to 48khz “Sampling” is Digitizing Waveforms Finite sample rate Typical 22khz, up to 48khz
SimPhonics, Inc. Analog/Digital - Digital/Analog
SimPhonics, Inc. Bandwidth Issues Nyquist Frequency –Maximum Usable Frequency is ½ Sample Rate –Assumes Ideal Conditions Nyquist Frequency –Maximum Usable Frequency is ½ Sample Rate –Assumes Ideal Conditions
SimPhonics, Inc. Bandwidth Issues Higher Sample Rates –More samples (memory & processor overhead) –Higher quality Lower Sample Rates –Less samples, lower quality of audio Typical Industry –CD quality audio is 44.1khz –Telephone quality is 8khz. Higher Sample Rates –More samples (memory & processor overhead) –Higher quality Lower Sample Rates –Less samples, lower quality of audio Typical Industry –CD quality audio is 44.1khz –Telephone quality is 8khz.
SimPhonics, Inc. Sample Bit Depths More Bits Per Sample –Higher Quality (Lower THD) Typical Industry –CD quality 16 Bit –Telephone quality is 12 Bit –Up to 24 With Gadget Labs System More Bits Per Sample –Higher Quality (Lower THD) Typical Industry –CD quality 16 Bit –Telephone quality is 12 Bit –Up to 24 With Gadget Labs System
SimPhonics, Inc. Sample Rate vs. Control Rate Processing Sample Rate –Processor Runs at Sample Rate –Processor Manipulates Samples –Very High Overhead Control Rate –Processor Runs at 20 – 30Hz –Processor Manipulates Buffers of Samples –At 22kHz SR, Buffer Would be 733 Samples, 1 Sec. Sample Rate –Processor Runs at Sample Rate –Processor Manipulates Samples –Very High Overhead Control Rate –Processor Runs at 20 – 30Hz –Processor Manipulates Buffers of Samples –At 22kHz SR, Buffer Would be 733 Samples, 1 Sec.
SimPhonics, Inc. Sample Rate Processing SimPhonics FX-30 System –Manipulate Individual Samples –DSP Iterates at Sample Rate SimPhonics FX-30 System –Manipulate Individual Samples –DSP Iterates at Sample Rate
SimPhonics, Inc. Control Rate Processing Much Lower Processing Rates –Typically 20 – 30Hz –Samples Are Stored As “Chunks” or Buffers Much Lower Processing Rates –Typically 20 – 30Hz –Samples Are Stored As “Chunks” or Buffers
SimPhonics, Inc. Which Technique to Use? Good Question PC Technology Can’t Operate at SR –Very Inefficient Dedicated DSP is Ideal for SRP –Big Bucks –Non Standard Good Question PC Technology Can’t Operate at SR –Very Inefficient Dedicated DSP is Ideal for SRP –Big Bucks –Non Standard
SimPhonics, Inc. When to Use SRP Mixing Low Latency Audio Input –Delays Using CRP are Unacceptable –Simulating Voice Systems (Intercoms, etc) Super Special Stuff –??? Mixing Low Latency Audio Input –Delays Using CRP are Unacceptable –Simulating Voice Systems (Intercoms, etc) Super Special Stuff –???
SimPhonics, Inc. New Technology and Standards Make CRP Work for Simulation Before DirectX, No Standard Mixing API Intel’s MMX Initiative –Intel and Microsoft Collaborate/Squabble Microsoft Launches DirectX® –DirectSound is a Subset of DirectX Before DirectX, No Standard Mixing API Intel’s MMX Initiative –Intel and Microsoft Collaborate/Squabble Microsoft Launches DirectX® –DirectSound is a Subset of DirectX
SimPhonics, Inc. DirectSound
SimPhonics, Inc. Sample Rate Conversion Important DirectSound Feature –Different SR Secondary Buffers are Combined –DirectSound Does the SRC Quality and Overhead User Configurable –Control Panel, Multimedia Icon Important DirectSound Feature –Different SR Secondary Buffers are Combined –DirectSound Does the SRC Quality and Overhead User Configurable –Control Panel, Multimedia Icon
SimPhonics, Inc. Using FXDirect with DirectSound
SimPhonics, Inc. Dynamic Control of Sounds Since DirectSound Performs SRC: –Frequency and Amplitude May be Controlled in Real-Time Since Any Waveform Can Be Used: –CRP Can Be Used in Most Cases for SRP. –I.E. Sine Wave Can Be Synthesized Off-Line and Used as a Secondary Buffer FXDirect Object Therefore, Don’t Let Them Tell You: –You can’t Use CRP for Simulation Systems Since DirectSound Performs SRC: –Frequency and Amplitude May be Controlled in Real-Time Since Any Waveform Can Be Used: –CRP Can Be Used in Most Cases for SRP. –I.E. Sine Wave Can Be Synthesized Off-Line and Used as a Secondary Buffer FXDirect Object Therefore, Don’t Let Them Tell You: –You can’t Use CRP for Simulation Systems
SimPhonics, Inc. Multiple Channels
SimPhonics, Inc. Practical Example
SimPhonics, Inc. FXDirect can use Almost Any Sound Card –Direct Sound Driver for Best Performance –Full Duplex for Voice I/O –WDM Driver Desirable FXDirect can use Almost Any Sound Card –Direct Sound Driver for Best Performance –Full Duplex for Voice I/O –WDM Driver Desirable FXDirect Operation
SimPhonics, Inc. FXDirect Operation Platform Shell Configure Menu Associates FXDirect Channels with Audio Outputs
SimPhonics, Inc. Channels Versus Outputs Multi-Channel Cards are VERY Rare –Most Do Not Use WDM Driver –Others Do Not Enumerate Channels Properly As of Today, Only Two Exist –Gadget Labs With Stage Research and SimPhonics Drivers –Echo Corporation’s Layla System Multi-Channel Cards are VERY Rare –Most Do Not Use WDM Driver –Others Do Not Enumerate Channels Properly As of Today, Only Two Exist –Gadget Labs With Stage Research and SimPhonics Drivers –Echo Corporation’s Layla System
SimPhonics, Inc. FXDirect Operation Stereo Channels are Actually 2 Outputs, Left and Right Stereo Channels are Actually 2 Outputs, Left and Right
SimPhonics, Inc. FXDirect Messages Message Area of the Platform Shell –Run-time and Initialization Messages –Always Look at this Area When There is Trouble Message Area of the Platform Shell –Run-time and Initialization Messages –Always Look at this Area When There is Trouble
SimPhonics, Inc. FXDirect Hands-on and Demo