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Интерактивная система просмотра системных руководств (man-ов)

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radio_xmit (6)
  • >> radio_xmit (6) ( Solaris man: Игры )
  • 
    NAME
         radio_xmit - radio broadcast utility
    
    SYNOPSIS
         radio_xmit [ -C ]  [OPTION=value ] ...
    
    DISCLAIMER
         This program is furnished on an AS IS basis as a  demonstra-
         tion of audio applications programming.
    
    DESCRIPTION
         radio_xmit is the Radio Free Ethernet (RFE) broadcast  util-
         ity.  (For  an overview of Radio Free Ethernet, refer to the
         radio(6) manual page.)  Though radio_xmit is  normally  ini-
         tiated  directly by the window-based xmit(6) program, it may
         also be used directly as a command-line program, or in  con-
         junction with a user-written window-based tool.
    
         In Normal Mode (the default case), radio_xmit  is  initiated
         with  a  set  of  broadcast options specified on the command
         line.  The program  immediately  begins  transmitting  audio
         data  over  the  network according to the currently selected
         options. The program will terminate on receipt of  a  SIGINT
         (<CTRL-C>).  If an input file is specified, the program will
         exit when the entire file has been broadcast.
    
         If -C is specified on the command line, radio_xmit  operates
         in  Command  Mode.  In  this  mode,  the  program  reads and
         processes command options from stdin and  writes  error  and
         status  information  to stderr.  Window-based tools use Com-
         mand Mode to  control  the  broadcast  program  and  receive
         status  information  for display.  When operating in Command
         Mode, radio_xmit requires that a station name and input file
         be  specified  explicitly,  and  the  START  command must be
         issued to initiate broadcasting.
    
    OPTIONS
         The broadcast options are  described  below.  If  an  option
         requires  a  value,  the  option name must be followed by an
         equal sign (=) and the value.  If an option takes an  ON/OFF
         value,  the  default is ON if the value is missing or poorly
         constructed.
    
         Station=[call letters]
               This option specifies the station call letters of your
               radio  station.  A  maximum  of four characters may be
               specified. In Normal Mode, the station  name  defaults
               to  the  first four letters of the current workstation
               hostname. However, it is preferable to supply  a  Sta-
               tion name on the command line.
    
         Input=[audio file or device name]
               This option specifies the audio input source for radio
               broadcast.  If a file is specified, it must be a legi-
               timate audio file (i.e., with  a  standard  Sun  audio
               file  header),  sampled  at 8 kHz. In Normal Mode, the
               audio input defaults to /dev/audio.
    
         Squelch=[ON/OFF]
               This option controls the behavior of  the  transmitter
               when  the audio input data is determined to be silent.
               When Squelch is enabled, silent data is not  transmit-
               ted over the network. This reduces the network traffic
               for stations  that  are  broadcasting  with  no  audio
               input.  Note  that  the  Station Identification packet
               continues to be transmitted every 5 seconds,  even  if
               the data broadcast is squelched.
    
               When Squelch is disabled,  all  audio  input  data  is
               always  transmitted.  Squelching only occurs for audio
               device input; audio files are not squelched,  even  if
               they contain silence. The Squelch option is enabled by
               default.
    
         Format=[COMPRESSED/UNCOMPRESSED]
               This option controls the format for audio data that is
               broadcast.  The  uncompressed  format  broadcasts 8000
               bytes of audio data each second. The compressed format
               sends  only  4000  bytes per second, but requires more
               computation on both the transmitter and receiver.
    
               Data format conversions only occur  for  audio  device
               input;  audio  files  are transmitted in the format in
               which they were stored.  By  default,  audio  data  is
               broadcast uncompressed.
    
         Agc=[ON/OFF]
               This option controls the behavior of an Automatic Gain
               Control  feature.  When  Agc  is  enabled,  the  audio
               recording volume is adjusted automatically to keep the
               input  signal  within reasonable bounds.  If the input
               signal is too loud, the record  volume  is  decreased.
               If  the  input  signal is determined to be present but
               too soft, the record volume is increased.
    
               Automatic Gain  Control  adjustments  only  occur  for
               audio device input; audio files are broadcasted at the
               level at which they were recorded. The Agc  option  is
               enabled by default.
    
         Autostop=[ON/OFF]
               This option controls the behavior of  the  transmitter
               when the audio input data has been silent for a length
               of time.  When Autostop is  enabled,  the  transmitter
               will sign off the station and stop broadcasting if the
               audio input has been  silent  for  60  seconds.   When
               Autostop  is disabled, the station continues to remain
               active.   This  option  does  not  interact  with  the
               Squelch  option,  although  the same criteria are used
               for determining whether or  not  the  audio  input  is
               silent.
    
               Autostop is only processed  for  audio  device  input;
               broadcasting always stops when an end-of-file has been
               reached on audio files. The Autostop  option  is  dis-
               abled by default.
    
         Address=[hostname|address]
               This option is used to configure the IP Multicast base
               address  that  the  radio_xmit program uses for broad-
               casting data.  The value  may  either  be  a  hostname
               (which  is  translated into an IP Multicast address by
               looking up the  name  in  the  NIS  hosts  map)  or  a
               specific numeric IP Multicast address.
    
               Normally, the address should end in 0 or 255, in which
               case an id-address and data-address are constructed as
               follows: the id-address consists of the  address  with
               the last byte set to 255; the data-address consists of
               the base address with a  randomly-selected  last  byte
               (0-254).  Station identification packets are broadcast
               to the id-address, and normal audio data  packets  are
               broadcast  to the data-address. This convention allows
               RFE receivers to register interest  only  in  the  id-
               address, so that audio data packets need not be repli-
               cated over network gateways until a receiver  actually
               tunes in to the station.
    
               If the IP Multicast address ends in a byte that is  in
               the  range 1-254, then the address remains unmodified,
               and both station and identification packets are broad-
               cast  to  that  address.   This  convention  allows  a
               specific multicast address to be used for  multi-party
               audio conferences.
    
               The default IP Multicast address is designated by  the
               hostname   RadioFreeEthernet.   The  special  hostname
               BROADCAST may be used to force the program to transmit
               UDP  Broadcast packets (which will not be relayed over
               a network gateway). The radio(6) manual page  contains
               more information on the RFE network implementation.
    
         Range=[hopcount]
               This option is used to configure the number  of  gate-
               ways  over  which  a radio broadcast may pass.  If the
               value is set to one, the broadcast will be  restricted
               to the current subnet.  The default Range is 8.
    
         Service=[service|port number]
               This option is used to configure the IP protocol  port
               number  used  to  identify Radio Free Ethernet network
               packets.  The value  may  be  either  a  service  name
               (which  is translated into a port number by looking up
               the name in  the  NIS  services  map)  or  a  specific
               numeric port number.
    
               The default port number is designated by  the  service
               name  radio.  The  radio(6)  manual page contains more
               information on configuring the port number.
    
         Report=[ON/OFF]
               This option enables the reporting, to stderr,  of  all
               changes in the transmitter status. It is normally used
               only in conjunction with Command  Mode  to  allow  the
               controlling program to maintain state.
    
         Buffer=[input buffer size in bytes]
               In normal operation, the RFE tools are  not  concerned
               with   the  delay  between  the  audio  input  at  the
               transmitter and  the  output  of  audio  data  at  the
               receiving  end.   Following  the model of radio broad-
               casting, the delay is not important  as  long  as  the
               transmitted data arrives in sequence and on time.  For
               this reason, and to ensure a consistent, uninterrupted
               flow  of  audio  data, the radio_xmit program normally
               uses a buffer size of around  8000  bytes  to  collect
               audio  input data before broadcasting. This results in
               an end-to-end delay of approximately  one  second  (or
               longer if the receiver's audio buffer backs up).
    
               For use with  real-time  audio  conferencing,  shorter
               delays may be desired.  For experimental purposes, the
               Buffer command is provided to alter the  input  delay.
               The  buffer  size is specified in bytes. For real-time
               experimentation,   a   reasonable   value    is    256
               (corresponding  to  approximately  1/32  of a second).
               Notice that a side-effect of lowering the input buffer
               size  is to lower the transmitted packet size, result-
               ing in an increased number of broadcast packets.
    
         Start This command is used to initiate broadcasting  accord-
               ing to the current parameter settings.  It is provided
               for  Command  Mode;  the  transmitter  is  enabled  by
               default in Normal Mode.
    
         Stop  This command is used to sign off the  current  station
               and  cease  broadcasting.  It  is provided for Command
               Mode operation.
    
         Quit  This command causes the radio_xmit program to exit. It
               is provided for Command Mode operation.
    
    EXAMPLES
         Example 1: Broadcasting over a network
    
         Let's say that you have a radio at work that you always keep
         tuned  to  your  favorite station (though you might shut off
         your speakers when you don't want to listen to it).  If  you
         connect  its output to your workstation audio input, you can
         broadcast the station over the network by using the  follow-
         ing  command  (the Autostop option will cause the program to
         sign-off and exit if you turn your radio off for a minute or
         longer):
    
         example% radio_xmit Station=KPFA Input=/dev/audio Autostop=on
    
         Example 2: Rescheduling a broadcast
    
         The following shell script may be scheduled to run every day
         at  6:00 AM to record a half-hour of news and rebroadcast it
         at a more sensible time:
    
         #!/bin/sh
         # Record from /dev/audio for 30 minutes (around 14 Mbytes).
         file=/bigdisk/sound/news
         audiorecord -t 30:00 $file
         #
         # If this runs at 6am, the news is over at 6:30.  Wait 3 hours til 9:30.
         sleep 10800
         #
         # Now broadcast the news on the network and remove the file when finished.
         radio_xmit Station=KPFA Input=$file
         rm $file
    
    SEE ALSO
         audiorecord(1), radio(6), radio_recv(6), xmit(6)
    
    
    
    


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