Dolby Virtual Speaker, Blackfin

The Dolby Virtual Speaker library for the Blackfin processor is a proprietary algorithm from Dolby Laboratories intended for creating 5.1 realistic surround sound effects with as few as two speakers.
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  • Output Status: Number of output channels, number of output samples per output channel, output channel configuration
  • API: C callable 'Push' API
  • Error Codes: Reports up to 3 unique error codes.
  • Compliance: Dolby compliance/certification requirements for Dolby Virtual Speaker
  • Code base origin: Dolby Virtual Speaker Implementation Development Kit, Issue 2.0
  • Reference Code Revision #: Revision 2.0
  • Certified processor: BF537
  • Framework dependencies: None. No dependencies on processor peripherals or registers.
  • Release Format: Object Code with source code wrapper
  • Input format: PCM 16/32-bit, non interleaved
  • Output format: 2/3/4/5 channels PCM 16/32-bit non-interleaved
  • Output buffer samples per block: X* Y, X = output channels (2, 3, 4, 5), Y = input block size. Both number of output channels and input block size are configurable by the user.
  • Sample Rate: All sampling frequencies specified by Dolby Virtual Speaker (32, 44.1 and 48kHz)
  • Multi-channel: Fully re-entrant and multi-instancing capable

Product Details

Dolby® Virtual Speaker is a propriety algorithm from Dolby Laboratories intended for creating realistic 5.1 surround effects with as few as two speakers. The Dolby Virtual Speaker uses the directional and phase characteristics of the audio data as well as room-modeling technologies to simulate a 5.1 Virtual surround sound reproduction system. Dolby Virtual Speaker can also produce surround effects from stereo sources when used in combination with Dolby Pro Logic II. This module can only be shipped to pre-approved Dolby "qualified recipients."


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Each module supports the Analog Devices, Inc. (ADI) Blackfin or SHARC Processor family and is a licensed product that is available in object code format. Recipients must sign or accept a license agreement with ADI prior to being shipped or downloading the modules identified in the license agreement.

Performance Metrics

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MIPS summary:

 Code memory (KiB)
 Data RAM (KiB)
 Constant Data Tables (KiB)

  • MIPS measured using Fs = 48 kHz, optimal memory layout, worst case test vector, 5.1 input channels and 5 output channels running on a ADSP-BF537.
  • Code compatible across all BF5xx processors.
  • "Data RAM" for one instance, includes Stack, Scratch, Instance, State, six single-buffered input buffers and five single-buffered output buffers, each buffer containing 128 16-bit samples.
  • The number of input samples to be processed per channels is configurable and affects the overall memory requirements of the module.

Systems Requirements

  • Windows XP Professional SP3 (32-bit only).
  • Windows Vista Business/Enterprise/Ultimate SP2 (32-bit only). It is recommended to install the software in a non-UAC-protected location.
  • Windows 7 Professional/Enterprise/Ultimate (32 and 64-bit). It is recommended to install the software in a non-UAC-protected location.
  • Minimum of 2 GHz single core processor, 3.3 GHz dual core is recommended.
  • Minimum of 1 GB memory (RAM), 4 GB is recommended.
  • Minimum of 2 GB hard disk (HDD) space is required.

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