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wProcessType Value
CHORUS_PROCESS 0x05
DYN_RANGE_COMP_PROCESS 0x06
A.8 Audio Class-Specific Endpoint Descriptor Subtypes
Table A-8: Audio Class-Specific Endpoint Descriptor Subtypes
Descriptor Subtype Value
DESCRIPTOR_UNDEFINED 0x00
EP_GENERAL 0x01
A.9 Audio Class-Specific Request Codes
Table A-9: Audio Class-Specific Request Codes
Class-Specific Request Code Value
REQUEST_CODE_UNDEFINED 0x00
SET_ CUR 0x01
GET_ CUR 0x81
SET_ MIN 0x02
GET_ MIN 0x82
SET_ MAX 0x03
GET_ MAX 0x83
SET_ RES 0x04
GET_ RES 0x84
SET_MEM 0x05
GET_ MEM 0x85
GET_STAT 0xFF
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A.10 Control Selector Codes
A.10.1 Terminal Control Selectors
Table A-10: Terminal Control Selectors
Control Selector Value
TE_CONTROL_UNDEFINED 0x00
COPY_PROTECT_CONTROL 0x01
A.10.2 Feature Unit Control Selectors
Table A-11: Feature Unit Control Selectors
Control Selector Value
FU_CONTROL_UNDEFINED 0x00
MUTE_CONTROL 0x01
VOLUME_CONTROL 0x02
BASS_CONTROL 0x03
MID_CONTROL 0x04
TREBLE_CONTROL 0x05
GRAPHIC_EQUALIZER_CONTROL 0x06
AUTOMATIC_GAIN_CONTROL 0x07
DELAY_CONTROL 0x08
BASS_BOOST_CONTROL 0x09
LOUDNESS_CONTROL 0x0A
A.10.3 Processing Unit Control Selectors
A.10.3.1 Up/Down-mix Processing Unit Control Selectors
Table A-12: Up/Down-mix Processing Unit Control Selectors
Control Selector Value
UD_CONTROL_UNDEFINED 0x00
UD_ENABLE_CONTROL 0x01
UD_MODE_SELECT_CONTROL 0x02
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A.10.3.2 Dolby PrologicÔ Processing Unit Control Selectors
Table A-13: Dolby Prologic Processing Unit Control Selectors
Control Selector Value
DP_CONTROL_UNDEFINED 0x00
DP_ENABLE_CONTROL 0x01
DP_MODE_SELECT_CONTROL 0x02
A.10.3.3 3D Stereo Extender Processing Unit Control Selectors
Table A-14: 3D Stereo Extender Processing Unit Control Selectors
Control Selector Value
3D_CONTROL_UNDEFINED 0x00
3D_ENABLE_CONTROL 0x01
SPACIOUSNESS_CONTROL 0x03
A.10.3.4 Reverberation Processing Unit Control Selectors
Table A-15: Reverberation Processing Unit Control Selectors
Control Selector Value
RV_CONTROL_UNDEFINED 0x00
RV_ENABLE_CONTROL 0x01
REVERB_LEVEL_CONTROL 0x02
REVERB_TIME_CONTROL 0x03
REVERB_FEEDBACK_CONTROL 0x04
A.10.3.5 Chorus Processing Unit Control Selectors
Table A-16: Chorus Processing Unit Control Selectors
Control Selector Value
CH_CONTROL_UNDEFINED 0x00
CH_ENABLE_CONTROL 0x01
CHORUS_LEVEL_CONTROL 0x02
CHORUS_RATE_CONTROL 0x03
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Control Selector Value
CHORUS_DEPTH_CONTROL 0x04
A.10.3.6 Dynamic Range Compressor Processing Unit Control Selectors
Table A-17: Dynamic Range Compressor Processing Unit Control Selectors
Control Selector Value
DR_CONTROL_UNDEFINED 0x00
DR_ENABLE_CONTROL 0x01
COMPRESSION_RATE_CONTROL 0x02
MAXAMPL_CONTROL 0x03
THRESHOLD_CONTROL 0x04
ATTACK_TIME 0x05
RELEASE_TIME 0x06
A.10.4 Extension Unit Control Selectors
Table A-18: Extension Unit Control Selectors
Control Selector Value
XU_CONTROL_UNDEFINED 0x00
XU_ENABLE_CONTROL 0x01
A.10.5 Endpoint Control Selectors
Table A-19: Endpoint Control Selectors
Control Selector Value
EP_CONTROL_UNDEFINED 0x00
SAMPLING_FREQ_CONTROL 0x01
PITCH_CONTROL 0x02
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Appendix B. Example 1: USB Microphone (Informative)
B.1 Product Description
The device described here is a USB Microphone. It is a very simple device that has no Audio Controls
incorporated. It delivers a mono audio data stream to the Host over its AudioStreaming interface. The
used Audio Data Format is 16-bit 8KHz PCM. The synchronization type is Asynchronous Source. It uses
its internal clock as a reference. The following figure presents the internal topology of the microphone.
AudioStreaming
Interface
AudioControl
Interface
Audio Function
Desktop Microphone IT OT USB IN Endpoint
Figure B-1: USB Microphone Topology
The audio function contains one Input Terminal that represents the actual microphone pick-up element,
followed by the Analog-to-Digital Converter (ADC). The digital output stream of the ADC enters the
audio function through the single Output Pin of the Input Terminal. Because there is no further processing
on the audio stream, the Input Terminal is directly connected to the Input Pin of the Output Terminal. The
Output Terminal is the representation within the audio function of the USB IN endpoint that eventually
delivers the audio data stream to the Host. The internals of the audio function are presented to the Host
through the (mandatory) AudioControl interface whereas the USB IN endpoint resides in the
AudioStreaming interface.
B.2 Descriptor Hierarchy
This USB Microphone device includes the AudioControl interface (interface 0) and a single
AudioStreaming interface (interface 1). The AudioStreaming interface features two alternate settings. The
first alternate setting (Alternate Setting 0) has zero bandwidth associated with it so that switching to this
alternate setting effectively frees all allocated bandwidth on the USB for this device. Zero bandwidth is
indicated by the lack of a streaming endpoint. Alternate Setting 1 is the operational part of the interface
and it has one isochronous IN endpoint. Figure presents the descriptor hierarchy.
最終更新：2011年05月02日 03:21
