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11641 spelling mistakes in section 7d of the manual


  48 
  49        An audio data format is characterized in the audio driver by four
  50        parameters: sample Rate, encoding, precision, and channels. Refer to
  51        the device-specific manual pages for a list of the audio formats that
  52        each device supports. In addition to the formats that the audio device
  53        supports directly, other formats provide higher data compression.
  54        Applications can convert audio data to and from these formats when
  55        playing or recording.
  56 
  57    Sample Rate
  58        Sample rate is a number that represents the sampling frequency (in
  59        samples per second) of the audio data.
  60 
  61 
  62        The audio mixer always configures the hardware for the highest possible
  63        sample rate for both play and record. This ensures that none of the
  64        audio streams require compute-intensive low pass filtering. The result
  65        is that high sample rate audio streams are not degraded by filtering.
  66 
  67 
  68        Sample rate conversion can be a compute-intensive operation,
  69        dependingon the number of channels and a device's sample rate. For
  70        example, an 8KHz signal can be easily converted to 48KHz, requiring a
  71        low cost up sampling by 6. However, converting from 44.1KHz to 48KHz is
  72        computer intensive because it must be up sampled by 160 and then down
  73        sampled by 147. This is only done using integer multipliers.
  74 
  75 
  76        Applications can greatly reduce the impact of sample rate conversion by
  77        carefully picking the sample rate. Applications should always use the
  78        highest sample rate the device supports. An application can also do its
  79        own sample rate conversion (to take advantage of floating point and
  80        accelerated instructions) or use small integers for up and down
  81        sampling.
  82 
  83 
  84        All modern audio devices run at 48 kHz or a multiple thereof, hence
  85        just using 48 kHz can be a reasonable compromise if the application is
  86        not prepared to select higher sample rates.
  87 
  88    Encodings
  89        An encoding parameter specifies the audiodata representation. u-Law
  90        encoding corresponds to CCITT G.711, and is the standard for voice data
  91        used by telephone companies in the United States, Canada, and Japan. A-
  92        Law encoding is also part of CCITT G.711 and is the standard encoding
  93        for telephony elsewhere in the world. A-Law and u-Law audio data are


 126          Signed Linear PCM   8-bit      Mono or Stereo
 127          u-Law               8-bit      Mono or Stereo
 128          A-Law               8-bit      Mono or Stereo
 129 
 130 
 131 
 132 
 133        The audio mixer converts all audio streams to 24-bit Linear PCM before
 134        mixing.  After mixing, conversion is made to the best possible Codec
 135        format. The conversion process is not compute intensive and audio
 136        applications can choose the encoding format that best meets their
 137        needs.
 138 
 139 
 140        The mixer discards the low order 8 bits of 32-bit Signed Linear PCM in
 141        order to perform mixing. (This is done to allow for possible overflows
 142        to fit into 32-bits when mixing multiple streams together.) Hence, the
 143        maximum effective precision is 24-bits.
 144 
 145 FILES
 146        /kernel/drv/audio
 147                                     32-bit kernel driver module
 148 
 149 
 150        /kernel/drv/amd64/audio
 151                                     64-bit x86 kernel driver module
 152 
 153 
 154        /kernel/drv/sparcv9/audio
 155                                     64-bit SPARC kernel driver module
 156 
 157 
 158        /kernel/drv/audio.conf
 159                                     audio configuration file
 160 
 161 
 162 ATTRIBUTES
 163        See attributes(5) for a description of the following attributes:
 164 
 165 
 166 
 167 
 168        +--------------------+-----------------+
 169        |ATTRIBUTE TYPE      | ATTRIBUTE VALUE |
 170        +--------------------+-----------------+
 171        |Architecture        | SPARC, x86      |
 172        +--------------------+-----------------+
 173        |Interface Stability | Uncommitted     |
 174        +--------------------+-----------------+
 175 
 176 SEE ALSO
 177        ioctl(2), attributes(5), audio(7I), dsp(7I)
 178 
 179 
 180 
 181                                 August 3, 2009                       AUDIO(7D)


  48 
  49        An audio data format is characterized in the audio driver by four
  50        parameters: sample Rate, encoding, precision, and channels. Refer to
  51        the device-specific manual pages for a list of the audio formats that
  52        each device supports. In addition to the formats that the audio device
  53        supports directly, other formats provide higher data compression.
  54        Applications can convert audio data to and from these formats when
  55        playing or recording.
  56 
  57    Sample Rate
  58        Sample rate is a number that represents the sampling frequency (in
  59        samples per second) of the audio data.
  60 
  61 
  62        The audio mixer always configures the hardware for the highest possible
  63        sample rate for both play and record. This ensures that none of the
  64        audio streams require compute-intensive low pass filtering. The result
  65        is that high sample rate audio streams are not degraded by filtering.
  66 
  67 
  68        Sample rate conversion can be a compute-intensive operation, depending
  69        on the number of channels and a device's sample rate. For example, an
  70        8KHz signal can be easily converted to 48KHz, requiring a low cost up
  71        sampling by 6. However, converting from 44.1KHz to 48KHz is computer
  72        intensive because it must be up sampled by 160 and then down sampled by
  73        147. This is only done using integer multipliers.
  74 
  75 
  76        Applications can greatly reduce the impact of sample rate conversion by
  77        carefully picking the sample rate. Applications should always use the
  78        highest sample rate the device supports. An application can also do its
  79        own sample rate conversion (to take advantage of floating point and
  80        accelerated instructions) or use small integers for up and down
  81        sampling.
  82 
  83 
  84        All modern audio devices run at 48 kHz or a multiple thereof, hence
  85        just using 48 kHz can be a reasonable compromise if the application is
  86        not prepared to select higher sample rates.
  87 
  88    Encodings
  89        An encoding parameter specifies the audiodata representation. u-Law
  90        encoding corresponds to CCITT G.711, and is the standard for voice data
  91        used by telephone companies in the United States, Canada, and Japan. A-
  92        Law encoding is also part of CCITT G.711 and is the standard encoding
  93        for telephony elsewhere in the world. A-Law and u-Law audio data are


 126          Signed Linear PCM   8-bit      Mono or Stereo
 127          u-Law               8-bit      Mono or Stereo
 128          A-Law               8-bit      Mono or Stereo
 129 
 130 
 131 
 132 
 133        The audio mixer converts all audio streams to 24-bit Linear PCM before
 134        mixing.  After mixing, conversion is made to the best possible Codec
 135        format. The conversion process is not compute intensive and audio
 136        applications can choose the encoding format that best meets their
 137        needs.
 138 
 139 
 140        The mixer discards the low order 8 bits of 32-bit Signed Linear PCM in
 141        order to perform mixing. (This is done to allow for possible overflows
 142        to fit into 32-bits when mixing multiple streams together.) Hence, the
 143        maximum effective precision is 24-bits.
 144 
 145 FILES




 146        /kernel/drv/amd64/audio
 147                                     Device driver (x86)
 148 
 149 
 150        /kernel/drv/sparcv9/audio
 151                                     Device driver (SPARC)
 152 
 153 
 154        /kernel/drv/audio.conf
 155                                     Driver configuration file
 156 
 157 
 158 ATTRIBUTES
 159        See attributes(5) for a description of the following attributes:
 160 
 161 
 162 
 163 
 164        +--------------------+-----------------+
 165        |ATTRIBUTE TYPE      | ATTRIBUTE VALUE |
 166        +--------------------+-----------------+
 167        |Architecture        | SPARC, x86      |
 168        +--------------------+-----------------+
 169        |Interface Stability | Uncommitted     |
 170        +--------------------+-----------------+
 171 
 172 SEE ALSO
 173        ioctl(2), attributes(5), audio(7I), dsp(7I)
 174 
 175 
 176 
 177                                January 10, 2020                      AUDIO(7D)